POPULAR Telescopic HOW TO AND Astronomy MAKE A WHAT TO TELESCOPE 2-INCH SEE WITH IT, BY A. Dtmonsttafor FOWLER, A.R.C.S., 0/ Astronomy^ F.R.A.S., College of Science^ Royal London. ILLUSTRATED. THOMAS R O Y NEW WIIITTAKER, 2 " K 3, 1896. \All Rights Rese"ved\ "J I " : BIBLE HOUSE. DEPARTMENT l"LAJSJi OF STANFOED EDUOATIOr JUNIOE UNIVERSITY PREFACE. The aim of telescope have the the how equal brought within finished of recreation will be found of beauties that such its by the of of revealing and of the practice is who those themselves indicate to briefly telescope a of of instruction amount telescope of of provide and A scenery, ounce reach to maximum use. celestial "an the astronomical an telescope, or a quite capable the how instrument, obtain can power, show inclination or possessor and realise is to means highly a little book be may not with this inches 2 aperture of many the observer worth larger will soon of pound a theory." The is method similar to and Practiced with great Norman use described that Work in Lockyer's courses both The Eyre the in my small " book of own and attend who Astronomical of objects for but I price Is. at South is observation in Spottiswoode, adopted Professor Physics experience instruments, is followed Demonstrations Physics* students selection and telescope which Astronomical entirely on large the in the by almost of constructing success Kensington. based of teaching am the indebted iv PREFACE, Celestial Webb's to valuable C"ymmon for for Telescopes much information. For the with the benefit the be to indicate attention possible I the whereabouts the is than of been thought and naming of maps complete more the may beginner himself for but stars, the on acquaintance has it astronomy, chapter first stars not are ciently suffi- to necessary the tification iden- objects to which directed. is Finally, a their making of include of intended those study to the of outdoor advisable put Objects that say in the and have I path right making chiefly for endeavoured seeing as to much from deductions correct as observations. his I have suggestions, to thank and Mr. assistance C. P. in Butler reading for proof several sheets. A. London^ October, 1895. valuable Fowler, CONTENTS.' I. CHAPTER MAKE TO HOW A TBLESOOPE. PAOK Optical of parts and tube cell The tube." for The required. " the of the " object-glass. the Squaring Focussing. " Works distances. of The Draw telescope 1 II. FEW HINTS. " field Estimation of of view. angular lists Working reference. " The power." weather." Observing " eye-piece." image Magnifying " telescope " CHAPTER A The " instrument completed inversion The object-glass." The adapter." stand. Materials telescope. a .12 . CHAPTER HOW Star star names." LEABN TO THE III. NAMES Star seasons. " maps. CHAPTER to the observe the Sun." Sun's STABS. THE How to " the use 18 maps . SUN. Sun-spots." rotation." OF IV. THE How . The The faculae.- inclination of the To strate demon- Sun's axis. " To zones." mark out Sun's the of Periodicity and poles Sun-spots." The equator." Eclipses of the Sun-spot Sun 29 . CHAPTER THE An interesting "Earth-shine." study." The The " . V. MOON. varying appearances." Seas."" Craters." The Ring terminator. Mountains and POPULAR ASTRONOMY. TELESCOPIC CHAPTER HOW Optical of a distant lens is called the the As coloured flint are the such to For be a limited same serves of image an of combination or lenses, Technically, the first O.G., while the objective, or lens simple a this of consisting those by of effects colouring of the convex lens of curvatures the scope tele- a plano-convex the of in double a or combination, properties surrounded are employed concavo-convex, number of for the perfect more of the parts one of kinds two are other. the glass nearly as Such as lens a is achromatic. but at a neutralised lens convex the form to object-glass one, optical that possible said In lens image. by the and glass. and lenses formed lens crown-glass a essential " eyepiece. compound a lens, a this fringes, is of (2) (1) " object-glass, images The telescope. are the TELESCOPE. A a magnify to constitutes second by and object, which with of telescope refracting a MAKE TO parts I. These lenses. time to give eyepiece eyepieces are a made large of astronomical an are obtained nearly field double ordinary an purposes, scope, tele- by achromatic, of view by a bination com- and using of the lenses The placed for For the O.G. the eyepiece. These the distance the adjustment need be the for focus. A wooden commended re- astronomical J inch results focal length. 1\ diameter, inches their focal made for method inch length. varying order methods possible J positions proper eyepiece, in Besides " making of here give to doing indicated the lenses, the following telescope according a the to : " papier-mache of better will length. and the cheapest 3 inches provision that length. absolutely. for given focal in The focal the course, and diameter and inches even of about lens A " O.G. required. instructions tube are quality. 1 inch and infinite,so required A diameter mounted between Materials will in other, and followed be not 1 inch be to each almost are better 1 inch lens 30 of although, ; of diameter A are to lens lenses eyepiece. length. lenses purpose lens in 1 inch respect this small a qualities, but various the A " additional an in with are lens had beginner's the focal with be obtained For of construction focal apart. easily procured, are 2J"iiich achromatic A " is to serve A of ratio distance proper which certain a " This For the of glass the at lenses, following telescope : of kind same and lengths,* ASTRONOMY. TELESCOPIC POPULAR 2 zinc, 27 inches or cylinder (No. 1) 12 inches long, 2J internal long, a diameter. little larger in very than O.G. meter dia- (say Vj in.). " (No. 2) " 6 A " larger trifle "" than " (No. 3) ,, ^th 6 " " of an in eye inch larger than Several sheets Thick of brown paper eye in meter dia- lens. cartridge paper. or to make sufficient cardboard diameter lenses. about discs 3^ inches half-a-dozen in diameter. Paste glue. or Indian ink Beady-made obtained * The a very focal sun, / rrlce or other Jiat at end well as reasonable length lens ink. stencil tubes, of the distance of the at or of from as rate a lens a piece distant of book. may of object. the wooden from be paper the cylinders and can be Publisbers.t readily determined on lenses, which it produces by measuring a distinct the image HOW The telescope be must inches ; but required made of O.G. an tube where by rolling brown mahogany, The which of may the on an inch not be greater of only wanted, on is than the diameter probably single a should inches. one be may sible. acces- be about of the The be 27 is most tube should about long cylinder whichever the paper, ment instru- they a of 2^ exacUy if glue tube, diameter if made tube, brass a It are the be focus. made with paper internal eighth an or inches several of should it ready 3 tube main and of 30 a TELESCOPE, The rigid, purchase to A tube." very for long cheaper be MAKE TO O.G., thickness nearly of of quarter a inch. an Tubes of made sheet also zinc the answer purpose very welL The cell of the place at part its rub used, the the In the on each press remove Trim of which and 1, is of roll a the the tube from the ends of be will the about sufficient longitudinally A* patched when them O.G. the A {seeFig. 2). nearly as tube *This will method be well glue rolling the at smaller diameter. before cylinder tube and six inches B them put the time be of complete and good plan to quite dry. pieces, each two these Calling fit to and cut nicely A out inside object-glassbetween in spent right angles at that paste, or halves, two wooden removal a a it is long. enable and is it in cut into little extra the It possible. in cylinder the the to laid facilitate to applying as possible involves arrived by as deal a paper again, up if the this lens thickness a the before the On tube, give respectively, divide B ; and of object principal such to tube chalk firmly as the support tube rolling the layer The telescope tube. main French cylinder to paper the it with tube. turn end nicely inside it fits object-glass." instrument No. cylinder the for to the making the length of out. least internal expense, tubes on but the another same wooden result may cylinder be of POPULAR 4 As adornment an of consisting attached eye has " lens, while focal be a diameter inches the pieces in a tube equal with the be may of From of inch an d diaphragm the No. inner between this them, outside off piece a O.G. cell, it slide tube, c),and long {h and on. make to lenses the of the enough this so 3 ; cut case should the and " of the sum with to field " lenses until 2 in the out cut piece. No. the the inch, cylinder as of is half one cylinder that that piece, eye- close comes eyepiece, be negative or eyepiece extra should and ^f ths a flange a card stout which them first our on to uncut about of lens between for remainder, inside instrument, one-third long (a.Fig. 1),and, slit the the Huyghenian length distance paper is of is, the ; for apart to, the Roll " thus, : the that distance inches two referred 2^ the In " focal a lengths end object-glasscell. lens eye ASTRONOMY, thicknesses two or eyepiece. the this to one the to The the TELESCOPIC two cut them insert being of made g Pig. thin card inch may e ink in its deep, he glued. inch an or place by cut op brass, and half indian with -Detah^ sheet about centre lens or 1." from stencil means the (fall size). Eyepiece the having a clean Blacken diameter. ink, of a and when dry, ring, about remainder Similarly, support of cut the the an small field hole in the the inside fix the of eighth tube lens / eye ; in an this its HOW place by do case of piece a tube it ; glue not MAKE TO end of 5 TELESCOPE. half g be the ' inch an it should the project beyond A long enough tube, outer in long, only this slightly to facilitate to its removal. It remains now and eye lens, of cardboard diameter, It lens. If by with a central at be eyehole at that to of the slight modification in of As the lens. eye placed of about The of the cost inch an a in which cap, clean to the 1. it will field focal be at on looking through detected once is to provide On the for the that Fig. 2), and thick by and a six of means about 10 The that inches should eyepieces the have increases an rapidly inches on from the tube of such No. 3 and the axis The larger. in of draw to ness thick- (D, tube inch nearly ^th latter F^ glued the and a cylinder Fix part object-glass. principal make to care the the long. flanges F^ this inside nicely (A) of object telescope tube, roll another 1 slide of with The its distance firmly very position the as shown smaller tube to tube should be long. instrument." completed blackened in to the be must inch. an adapter." No. tube Fig. 2, taking parallel for a diameter lenses diaphragm of only require smaller the be diminishes. adjusting it will the eyepiece cylinder the already stated, and connect ; it will of will eyepiece extra consequence lenses length the described one quarter a the Draw-tube as of necessary Fig. the of apart, and inch an aperture in of edge construction general similar D in central, not one it is A, cap, form the disc simple a -f^thsof about in be the over eyepiece. The as hole time a either may made any as eyehole centrally an This be is shown the it. may darkening a the to removed be may close it or place to internally,the Fig. 2, showing a various section Finally, parts of the may be instrument. after put being together It \xv^^ 6 POPULAR ASTRONOMY. TELESCOPIC O UJ o "L HOW MAKE TO be found of the tubes with others by rolling thin possibly they as All sand-paper, found are the dead-blacked be with If this for preferable outside The embellished or The with the a for made horizontal direction. This of which two A in. 5 consists of right angles about cut an inch so as to E, C and through them, tight ; in a the nut its at a adjustment must and desired any various ways, of be may IJ, X any for attaching other object wood-turner a made in hard wood C 6 the is fixed C the part upper connected allowing be D by to about end. extreme B thumb-screw and left. If A 1^ X B on C, ins. in A and nut is 1J ; X 2", should at be 2", when ; is fixed it when on and may A firmly thumb-screw a turn of not together for upright which used. screwed 8x2, a indicated 1^, 2" 4J X to be way be throughout, except are right more vertical in in at made or services thick. shorter for Provision pointed be pieces, each should screw with of and kind indispensable, arrived fence, a 4 admit D lamp enamel, some telescope, a be fairly wood half out of in., i? ; the of the may some two stand with proved im- described. support 4 X be with painted employed. be may the Fig. 3, provided about to it may If the obtainable, E that top hand. to comes in of here the sash, is ink may be almost are powers simple arrangement window A is result are prevent stencil mixed varnish, " movements so one, to fancy. to instrument two ink, instrument it may or ; stand. high the shellac black telescope especially when be of according supporting stencil should lenses the readily obtainable, appearance vegetable or easily. too or of according them, between ink some purpose. by coating black Indian reflections. internal tubes of diameters the over paper stifflyor parts of the inner of thickness the increase to or pieces fit too to reduce to necessary 7 TELESCOPE, A passing not screwed length, working are similarly which be attached will by nected con- admit sccewa POPULAR 8 by or bracket a held be may Fig. that so up, they the must small not it the Of readily suitable place, or most fence a so much required single fence be a for will both on tripod stand screwed position ; but prevent the the object if the insufficient sides of by fixing overcome about, be keeping be the moved to as post, When can of its slip out up right-of-way difficultycan object they not movements not to readily be can telescope straps. attached desired screwed a small two the certainly satisfactory. the to be by instrument course, has observer is telescope will continuous view. E on object, and arrangement made, pointed when and place this freed convenient any its shows are screws to in if well and in 4 ASTRONOMY. TELESCOPIC a it ; but in post the it if firm replace may this enough. Fig. 8." For but turned a lower the nicely attached a on as Parts of wood part vertical desired a Simple support, of C Support. Tblesoopb D is turned and and E remain hollowed cylindrical support, either to a tripod stand out which or before as post to may ; this ; fit be is BOW shoTn TO j9 in at MAKE A and Fig. 3, TELESCOPE. again on 9 in stand tripod a tbe frontispiece. Vig. The the at inversion be once ordinary that seen day would as be the the to this action of cause puzzling First, then, (Fig. 5a), the a let beam down. corrected by and light of the which is is no In ing insert- the piece eye- extra lenses, telescope, objection it one much as content are will absorption, collect to it by astronomical an there indeed, light things to see to it, long so mind. is of those to in astronomers in of surfaces Hence, borne the the object, objecl"glass loss a of and Although as involves from down, is the is through looking upside appears inversion functions possible. it this between this On terrestrial any image disadvantage a chief upside as since Sdppobt. image." at teleacopea reflection by the the lenses but ; Tblbscopb instrument additional of of completed and Simple i."K not the a text-book lenses inversion versed not it of be raay of the in parallel rays be not image optical understood optica, on that few a of out place, not seems words a as little matters. if we impinging have upon a lens, it in L tbe POPULAR 10 direction same rays a the as which point F^ TELESCOPIC from diverging parallelbeam. lens F the from be lens for called upon focal the the Next, same if we direction the the of which to a point) a the but glass action of parallel beam, axis this of point the will other or The from very the lens F distant and the is made. (Fig. 56), not lens, they be of Lbnsb" Telbscofb not as this distance surfaces two T as of the distance lens, and of the lens lens, according is,rays of have as that the parallel,the point the diverging. length the from not from and, similarly, ; side be the to converge focus one curvatures Showing will emerge on rays parallel rays, optical propert^iesof Fig. 5." J?' be or lens will farther or converging objects, is F if the are rays depends to the principal point a ; but nearer the the Whether is immaterial will of axis is called ASTRONOMY. will in the in still axis the verge con- of CHAPTER A examine the first results definition is angles it circle of signs any of of considerably If the guard to this of out the is length first and twice field eyepiece, has if show it before ceeding pro- himself the fitted and in of the object-glass its place, be must care If the focal focal compound of been product lens divided equivalent of length the eyepiece, telescope. the the described, of the by focal 12 focal their of length " the the and the taken defect. a power which eyepiece lens of magnifying rectly cor- evenly an and putting spiky, appear the by focus be star, corrected tightly too power. divided be equivalent the be this against purposely right- this square, convince may be square. will stars Magnifying glass by be be The at bright observed, should it possible not if a O.G. be observer object-glass of images The the will light ellipticity further. importance If best is see to should object-glass it To telescope focus. of the is, if telescope. the direct out illuminated the the to employed. if that ; telescope lenses the " of if affected on proceeding the interest, from seriously axis placed, observe obtained Before determine to squared " the to order most properly not of objects in be will HINTS, object-glass." various tested, be FEW the Squaring IT. eyepiece, the objector quotient the For of lengths Thus, will be " the gives form equivalent sum. length the of focal the for eye the FEW A HINTS. 13 2x3x1 . ,, " for and the second , li inches. = " g ^ " 2xlixi = . focal if the Then, magnifying the with O.G., For of be 60 with of length be focal of and 20, of length the increases eyepiece, of the of both powers will second and length being the simple plan, from powers 20 simply fourth will referred the while with the field will hand at himself sequel, and 20, 30, 40, as the power has the field the provided has the magnifying a observer In that meaning give as near eyepiece magnifying if he to pretty inch, an described. eyepieces be 60 to first the eyepiece this "y the well very kept lens remaining second the if in Thus, answers is object of examination the in lens simple a the as its focal times. range increase the inches, will eyepiece especially field. 30, lens "eye long so the of focal planet, a removed, be power a or eyepiece, lens first 30 be objective general, purposes, stars centre the In of the power. many double an 40. reduction magnifying of with second or i + length power " "^^^" = " H these the 60, alone lens is employed. The on with powers For one. to 60, but will be results The when The beginner observing if, while will true is such observing see the apt an with image to one however, which of the as eye, the he the then be 120 or may good very a of power 20 is be moon keeps observed. magnification the evident. stars, gives satisfactory apparently projected amplification will 100 as objects to under-estimate object double and object-glass be power for each high as if the lowest indicated planets, powers observations, many effective. most the up the craters, occasionally employed be he lunar spots, sun object-glassesperform satisfactorily achromatic cheap or the on A a planet, but other the power open, sky, and of 60 POPULAR 14 for will show instance, the to TELESCOPIC in Jupiter diameter apparent ASTRONOMY. of this the moon about be to way with seen as equal the aided un- eye. Some and 2-inch for objectives have with these, will powers however, is and, the on be the each increased whole, by the the reduction 30-inch 40 This of the lenses inches, magnifying one-third. by a of length eyepieces, same accompanied focal a gain, field of view, perhaps are to be preferred. field The of view is ^The " half about a the (in England)^ horizon the star a When the of case brought the to on of centre above be may will the give diameter, circle great a is under examination, the field of the where view, as it should that crater, it is important lunar a four to time 40" field by moon, of hours. particular object any divided field the about the 360" traverses 24 aiid corresponding arc the Or, across pass seconds of in sphere diameter. south, to of situated so celestial the number of minutes number since star the and noted, due nearly required by of the by observing in degree a diameter angular estimated roughly be may which view. of in be tion defini- is best. Focussing. sufficient best to inside that on be care and of does is observers if not too focus, it the eye perform not great variation is apt is draw tube both it is only in this way If to its functions in It the found. be can as unless employed. are of means best focus, especially the to powers its at seen the only strain moved itself,and under the best focus for different is the best guide surprising. weather. Observing kind for be regard true focus, the The conditions. the of the place proper consequently to eyepiece by outside side one will with taken the move the object higher magnifying the when ^No " of " sky adapted thick, are by no Experience for means observations. detrimental Fogs for or as haze, observa- of tions the sun, for of the views a It the is this but purposes, of stars, the as nights less of from the of to favourable un- Excellent through small on for that case for astronomical for observations than large telescopes, and observing nebulse. distances. In " heavenly bodies, they are which so worth it is sometimes recognised while bearing moon are each slightly over stars which form the the defining degrees many are ever, This, how- unsteady. very when frosty nights, the often other or clear means are therefore and sun nebulse. especially good no stars is that angular state well-known It by best planets convenient obviously frequently obtained are are effect the are Estimatioii positions is images far has and comets imagined sparkling, are planets, though as named 16 haze. or commonly stars such things objects slight fog and moon, such HINTS. FEW A minutes or without culty. diffi- in that mind half in degree a diameter. three The which sometimes are for employed the same in stars the (Fig. 6), are be can all the 5 is about wishing to For AlmanaCy as this to this for the between the the two Pole star they as purpose, distance also justify to Perhaps nearly ; the better none a these between it tells professional little book are for him him this data to be he which The more the wants are star little than the published than is handier astronomer. intended is telescope, able. indispens- purposes which what a almost general exactly with possessing almanac an almanac beginner burdening Anyone " it, will find Whitaker'a of shilling. the use is There without reference. of edition round year distance 2), degrees. Works and point be may made be degrees. adapted better even seen which Plough, thus angular three (seeMap Yardstick, and The is about stars extreme two the as purpose, popular designation. the to known of Orion belt maps at Nautical to know, chiefly of included than a an use in intro- POPULAR 16 duction TELESCOPIC the to constellations, sufficiently detailed are objects to these, the Among smaller with excellent his observatory with the in objects much hours that and what to he order and work goes to to his shall do beforehand is in such only by be can advance to it for get we much reference a in valuable student the carefully prepared investigation, of Atlas astronomer as examined be to of so fine list A line doubt any late bodies. and evening, the by stars, heavenly systematic clear a removes that few the The " " particular preparation the available. are furnish the desired "An and moon of be Atlas," will they most it useful. most the If atlases Ball, to as instrument. indicates any of on list his the of places Star that hoped made. be New " Robert Sir lists. working of maps "Working the one the excellent many information valuable " is by Astronomy,"! will ones, Proctor,* A. it is though indicate to reference beyond go R. which to ASTRONOMY, accomplished observation in this country. Even find it excellent an imitate the himself of of instrument, of time which course, the follow, visible make such in be times, * or 30 Longmans an having times " As prepared instrument an telescope, when Co. the price 5s. , to example, for only field in of observations an f G. in eyepiece lens the list is PhUip " various observer as the Son, lowing fol- February, magnifying removed the to chapters the a list a powers the enable such for such according visibility to prepare on given are of times 2-inch a lists. might with the to data will time, magnifying especially Sufficient as the to of and included objects more telescope, saving astronomer, The and 2-inch great a according vary year. objects to list. modest and advanced more would, the his plan, working a with beginner, a : " price 15s. 20 A FEW Working List Stars" Double HINTS. for 17 February. Arietis. K 7 11 X Gteminorum. Monocerotis. " Cancri. S CepheL K Ononis. i S Star Clusters Ursae Majoris. Pleiades. Double Praesepe. M 34 PerseL M 35 Geminorum. Cluster in Perseus. " M NebxQsd Great Majoris. Canis 14 Kebula Orion. in " Andromeda. " " Planets (1895)" Venus. Jupiter, Occasional Objects Aries. in Mars, in (1895)" Gemini Maximum of the variable star Mira. III. CHAPTER HOW Star When visible of matter probably that of much as than stars system some to be to and naming but, as hemisphere one But if even is it with, evident them identifying of ; 3,000. deal to clear a number the in as these on countless visible number the sky imagine alone eye amounts more no naked fact, never had one the to the at easily might one STABS, THE OF looking " evening, stars NAMES THE names. moonless a LEARN TO be must devised. Since the stars for positions of names long very divided been times preserve these and the the on of corresponding and countries, star as The as the the of the ones a Twins employed, at the upon town ; to out. the the the various For a is clear sary neces- sphere surface to into particular any constellations the letters Bull ; separate of the though not 18 always, in are and so Latin, on. for stars the " Greek alphabet " usually, only celestial earth's given the Taurus, the it tained, re- city. of least the name or given identification the of division look of logical mytho- conveniently constellations, divisions as usually Gemini, brighter to name names For are to of use them regard to the dying The from representing fast is maps derived still are of remote very constellations. chiefly names custom star understanding been these although called relative same from have they groups have groups sources, figures periods, into the nearly very in the order of POPULAR 20 tures identified are such the as of what stars Right and of north degrees Star depend the country, horizon northern north-east, Some of the from be may for night. in exactly the as round the which we the 4 mean see earth a degree time a the sun a earlier and do, evening will on each of the fact stars of sun at be of however, be times of time at ances dist- about will be be west, time earth of travels celestial we see the day, as sphere looking As year. days, to seen earth one the 365 are will visible. part in (the so the any the that course, and towards that succeeding degrees stars throughout sun 50 position, their set will overhead. same Some the in different the that so being " the the of near London, must, about part vary " day, the the year, clocks, which, movements east, of round travels minutes apparent the same. of stars groups once in the down than at the time, one nearly of sky at in heavens appear more change moon consequence sun from nearly certain in Again, the and sun them remain be They of the part for towards not round. places. the low latitude the apparent Pole the night only away this those in year looks one rise to seen it will different a During from hours set the all if year, six " the that at it will later never " seen looked the Pole the in appear hours constellations to reckoned Thus ; six another in are find soon observation. may Right equator. constellations of its hours, minutes, are will observer constellation a in celestial the time the upon this of positions apparent of the The " scope tele- a terrestrial to are Declinations the by which reckoned is while south seasons. latitude R.A., time, of possessor measurements " and or or the these, however, ; sufficientlydefined is Declination Ascension, Argelander aperture. star longitude seconds in inches general catalogue, some individually a and in of catalogue two cases, Ascension number a concern only all In by great scarcely will ASTRONOMY, TELESCOPIC that rise nearly reckoned by regulated by turns 360" is, in the 24 BOW hours, TO LEABN degree one t.6., accumulations of about so hours, 2 o'clock the at 8" o'clock the on the at end' of the end of and way, it identifying celestial of the well equally those at in given each maps. other surface, with of sort the in one hemisphere and this Planisphere, special In the the nearer for the the at for is not middle. * Published stellations con- 8, 10, and of in at at 12 this in assistance of The determining of hour any does any almost this Such stars on tables in with as omy," Astron- on a too will great, when to the be be may adopting employed long so as is but there show all forms of the little the stars the stellations con- scarcely recognisable, using such admirably the not reason by and world, spherical they maps to respect commonly attempts one the The maps. adapted best for its guide for defect of stars. the at top the of the this individual the times Lessons those to edges projection employed stars and Nevertheless, example, though 2, 3, 4, Maps of accuracy remembered is purpose, learning the be must about cost. single chart, a towards sky 10 at purpose. globe. map on south precisely represented If, however, distortion. due arrived Elementary of maps each by south means smaller projection, similar covered area due at be to amount showing Planisphere^ sufficient construction the similar celestial a ready positions be only on as a The " can represented some serve will the month a dates are 21 particular evening. in object much The month, a be meridian any very are will the STABS. minutes chap^r, visible Lockyer's " 352, Art. Star a this they the 4 which each and year, of month. furnishes any In that stars also globe in day of hoped the situation the in is minutes). month a on appear beginning THE stars of which P.M. the beginning the OF intervals that at maps 4 in these the at NAMES THE end is to of the In Map by G. of this increase the the the distances compared as maps 1, chapter, constellations Pbilip "^oti, y^^^*^* between with near those the edges the of much lines have Since omitted the the found in to the use with is Charles's and that which Major of when the balancing and lines be 1). estimates of horizon One a of these aids while 1 to memory. 1 Map connect repetition their " shows 2, 3, and equator. to 4 Maps are 4 show of connection the only stars with that line a " Pointers " gotten for- be in 6. side Fig. of the of stars to other passes Almost Pole Star, which form by imaginary way, constellations to be will above be the each Perseus and below will of the of the the Pole, celestial sufficientlyserve Map 1, will maps It may the examples surrounding to other. as stars joining those regarded stars edges the connecting lines, and down and of 2, 3, 4, respectively with at sky, to never nearly in this habit to the stars Vega, Capella, Maps northern of observation. of some Dipper, them, principal by imaginary constellation stars time Ursa " opposite the the be first of if they happen difficulty, falls into naturally the ^the indicated distance, will should observe " planet. a 1897 of stars, stars as the on in between Star, much the at found Proceeding (Map without found the Pole as Plough, Next, these Cassiopeise,the of W the as be distance Plough, found be sort north the through will the times 4 about of two end it on should map constellation the recognised. once through drawn of will the Acquaintance " to respect represented on the conspicuous seven Declinations identify to known This not to up maps. variously not simplicity, with be cannot taken portion Wain. consists be of and positions they planets VI. made be the Chapter How their bright body a sake will maps. that should of positions the Ascensions Kight these if Hence, noticed, steps The of in defects these For planets change maps. be or the stars, it is obvious star but consequence. indicating been ASTRONOMY. compressed, somewhat are found be a TELESCOPIC POPULAR 22 be worth and the indicate while mention to a the nearly on line from In using tion the stars south, Cassiopeiee the while Urare ^ the those as lower towards Ijeo the time part the of {Map be may the top will b" lies the nearly on 1), of obserTa- firat, aecond, 8, 10, will map lies date the on map 4) through 3) the ia handle the {Map Star (Map for ne"rlj very Pegaaus Majoris the lies forma Pole 4, look of bottom the and ; 2, 3, and according on from 2) of STABS. St* which stars Square drawn Maps linos Great THE Pou thb (Map of curve through a along third of and Arcturus the the ; line a side eastern a of Plough Ploooh that) also oontinuation of Thb 6." Fig. OF NAMES THE LBABN TO BOW or then e.Va^oRi'^ 12 be or p.m. due "^'s"t\iRa". ; POPULAR 24 For the be found shift of turn should If, object. be 4" of S. If for instance, found If be indicated at the way the refers sides that situation the of position only of those on of its by star a to give an place the such and must ordinary of object, given used map latitude of in its its exactly be and ably prob- hood. neighbour- the would as information whatever in view. will of stars scope tele- power map declination, be ated estim- observed, be to said the field source brighter is and 15), large is any mentally complete more R.A. maps will to magnifying a here the to the diflSiculty cluster be lowest unless it in 90") no star (p. to the necessary, it telescope will referred a must nearly from stars, the distance comet, it very from certain a order a overhead. mentioned not small a position to in object some be as employed to 21). in 38^" principal accordingly, readily stars, remains those example, this (p. polar directing already aid pointed first for will equivalent subtracted the in Sirius, the with being point experienced be desired the of Star while latitude knowledge north the (the being explained Pole times, through a of the all at London pass With to that place same already map positions hour one as the mind in latitude in of case borne the month, a the evening the interpolation, half the of hours by of In be other ASTRONOMY. TELESCOPIC nature, numbers the used longitude. same to find HOW TO LEABN NAMES THE Map OF THE STABS. 25 1. 8ispauiojpu\/ j^^i VI 3dOiS9 1 V3 9 M o oa 3 c o 7 ,\"" Oil "^ ^y ^/ V) PC / *^ ^.: "^ -*% '/"J a ^ 26 POPULAR ASTRONOMY. TELESCOPIC Map 2. 5ooow iH "sis? -fip. ^"5 60 28 POPULAR TELESCOPIC Map ASTRONOMY, 4. IV. CHAPTER SUN. THE At certain is of the additions heat to the for observer himself light the by How to take little or density; small in fitted inside and a so much neutral the better according In made general, by the sun, the tint the when a the magnified to the at dark conditions of larger will 29 be formed piece, eye- suitable observation. be can obtained, the observation. telescope so should the cover of piece eye- with glass to the the is sufficient blackness time of The image a telescopes observations image. to smoked be if safe plane glass green also can of made flame sun or this however, projecting candle a there of perfectly is When eyes. glass piece which the the always must directly, dark is small cap of to to at aperture, sun a method little adopted are the with A ; brought he to inches 2 observing with of piece devices than this brightness density, to smoked the If a proving necessary, that injury against instrument. an for winter is " observer covered merely It sun. more in been and ment, instru- in satisfaction have light little our great no of scope tele- a others. guard not danger no be be is telescope of use with giver great which would-be to though much the the precautions the of observe warn and facts the labours to outset, of interest, the find will some sun the from follow to the of knowledge likely are possible greatest our of observation the times required Special employed. are should sun being on be directed a sheet of POPULAR 30 will image held card or paper image A The the the frame but not short made to is shown in any the from and image, the eyepiece, thrown Sun-spots. exhibits It " visible to the part is naked much there size,it called and the is a nucleus will than The the still other outlines, times and only be may necessary the screen of the size the at paper should be part frequently in as the are the Some almost to most be that seen the as varied seen in and if of rule, a the spot times Someis of very are concentric two be which umbra^ spots to central penumbra. of the scope, tele- and part of the sun the sun-spots, darker is part with part, and, outer and the large enough the are spot. that case even inner exhibit the readily be darker of the they are the outer regular forms, appearing at tube, sunUght. it velvet or a about the of the examined These eye. darker umhra^ of setting cloth when spots distinctly outlined. is the for often very occasionally they considerable any is dark certain and card of distance ; frame. the over of pins travel to direct adjustment of piece A angle. proper from the of rotation movement a of admit to made or itself ; it is slightly changing which telescope, frontispiece, but suggests work. frame- to of the piece paper the in which way for provide drawing is to image light a object-glass end the at the screen frame a fitted ployed, em- obtained board, body A tube. the be be by drawing rotated, be cannot down square, help Such it and up attached the 20 the of thin a focus eyepiece. means of be can the projecting on fairly stiffly fit that so for made be sketch the from telescope by may should inches will to for way the to screen paper inches the to power will the from necessary If the of size card in diameter arrangement screen a 14 of the trial. by The eyepiece 3 inches of about convenient attach 12 about image distance a of the position found behind. distance the upon be must an at the ASTRONOMY, distance some depend eyepiece, and the TELESCOPIC circles ; irregular groups. The SUN. THE umbra is sometimes often change examining the details effective very is viewed of when eyepiece the When the be swallow less no miles, of dimensions a image The FaCUlSB. be sun, there than the noticed of rest It somewhat in demonstrate can instrument, A to the and series in forms easily be many of be move the sun's near the will quently fre- size. it of the brighter /aculce, and of spots of are seen near the sun of consequence of centre by of ; if is the That rotation." regarding drawings of the atmosphere. sun's the corded. re- about made much limb in centre, demonstrated facts the can been boundary are all across, is spots, c"Ued are that miles be apparent which that that have or the perhaps observed the of appears spot readily neighbourhood the which they diameter limbj These the and across be may added absorption taking place rotation, will near than enable reflects of sun's addition the be may darker globe the the disc. the especially brilliant limb. miles irregular patches, are do should if if he hundreds some reduce that these sun-spot smallest The which In " to scale earth, estimate will due will such A observer that spot any that sun any mind. 100,000 rough fact the tremendous whole is than may of the the addition. in edge, foreshortening noted. be screen directly, see the the up planets 860,000 massive the If in to Remembering To found be round. borne impressive more spots the will 60 the once. sun is turned telescopicallyobserved and at the viewing should other be on observing sun-spots, phenomena could For hours. telescope, when movement distinguished when it few a power eyepiece, but apparent suspected the 2-inch of the of the be to all the spot, a of course spots produced lenses partake them of common a the the on not the are directly. Some dirt on in which by bright bridges^ crossed to seen 81 the our means this sun, the system is of small rotation our can indicating in be the POPULAR 32 positions of The before he " " top the and the afternoon, The north the and passes limb is that towards the at with sun right the After the rule relatively the of of the image comes to be the image is to say, by hand western of disc is most meridian a great a ; the poles eastern as look we limb is on Turn the by one is sun the furnishes spot, a be centre or diameters the as that the western the of circle; this times of in sun's the parent ap- motion will in motion this of the sun's then the limb, and telescope be is is movement means the ; the distance in until by and one apparently image round screen of the will fact of Placing different at variation telescope, its and fills different sheets on eyepiece just the the diameter the image of convenient right angles. at slightly line the the the west northern When by the this adjust As the shown of diameters be screen, drawings. direction while respectively are left in right orientation." " cut is the size circles consequence to and as that on eye, screen, will in year, east disc celestial or trial what diameter. an east, limb called be the require the the that so adjustment across of marking might towards sun's through naked two the on screen the the of hand. and these of centre, (say 3 inches), draw of their far, however, means What sun. sun's the finding by paper, if the of time very some got away points the of drawings points the which circle have the lower passing through the that disc, and the proceeded of the will south and upper " that so show the on enough, necessity bottom mid-day at top places have not the perceives will day, to determined. will " day long be can observer ASTRONOMY, apparent continued across passage spots from their be drawings a the change spots TELESCOPIC along apparent edge, is ment, move- in advancing the the orienting edge slightly the edge which will raised one. sun is viewed inverted, so that directly through the eyepiece, the the will appear four points as in THE when Fig. 7b; Fig. projected on Fig. 7." view Direct naked with the taken Having for lettering them On will be that seen from the disc and 15, 1892, large spot visible a disc sketches, E. by while 8." Sun-Spots in seen on Imaqb. orient details the of positions the Astronomical an Telescope. Screen. a to of sun's in image various the spots, each, numbering or in visible sun's new a on op sketches Fig. 8. both days, rotation February, was c group movement made will It days, successive on apparent an Two W. shown the made sketches spots have to are Sun's of the W Fig. in as reference. the was S b As in such comparing N precaution sketch afterwards N projected As mark indicated, way S Orientation Eye. e and be W 8 the will they screen a 7c. W a 33 SUN, b was between brought across on be seen carried the to dates our Feb. 11 that the off the of the view. E 1892, HiLUStratinq Sun's it rotation. POPULAR 34 As TELESCOPIC sun-spots travel do enough to eastern limb. The the the drawings period travel would that is apparent the earth's of inclination The will found be The spots the disc, according observations while paths, March in of the the plane the sun. fact in sun " determined north northern the that with the the sun's travel the time about they J days. 27 in spots the same rotation is less made degree a ; but from of the the is, the of the for the day, the extended the equator is referred side curved This the axis sun's makes sun's makes of to its the sun's will the with stration demon- ecliptic " of the The to the journey round is about 6", perpendicular from of to as Hence, spots. course to round perpendicular the ; the equator." annual during south journey depart considerably disc to but they perpendicular and observations appear the obvious an is not a the September its annual axis which towards is all. across they paths, poles sun's in year ; in is this paths December lines north. sun latter and have Nor different the convex plane of the of straight earth point axis." in June earth by prolonged pole to the the out which in that inclination plane since days, days it increases In the in which mark actual the 25 over that they again towards convexity To disc the curved to made. are traverse the little a and 1 nearly roughly 14 being the on the sun's long poles. the have of last average orbit to seen again in its of the rate shown have observations to is period rotatiou mean in Allowance the at circuit time time. movement the under travelling be determine to On whole true round be not of them many utilised little a the the than to in earth, however, so be it must necessity come rotation. make direction, to also disc the of disc, but even sun's apparently The and may of the across the across this, will spots same completely formations, evanescent are that expected ASTRONOMY. the a the year, plane Fig. 9." drawing made the for axis equal 25 is drawn ca the crosses semi-minor the us is centre at E'Q an centre the as of table, indicated If it be and the and in desired 25, is drawn at of e'6q By this disc has to is a heliographic NCN' of tude lati- made is a to to this line. the CQ, and ah north point of where the semi-ellipse with it latitude south of case right angles construction a the position angle the angle h is the sun's the and G^**to Then in The J" W., March. in table 1892. The angle the this S. 6J" axis, and axis. of 25 Equator and use is parallel to e'q. made by the date this J", and Axis March on the of Sun's Thb illustrates 9 Fig. ASTRONOMY, TELESCOPIC POPULAR 36 pole is is equator ch as evident the that of 6^" S., as required is presented towards diagram. determine longitudes of the with spots, some use the tudes lati- made of precision may be THE Thomson's The belts, zones or These extend from limits. becomes This Periodicity of equally numerous means extending and in wane together ; while naked the to The it is probable until maximum show if the is two equator. sun's the outside these and equator which might wise other- be to seen From paratively com- free it has of they the sometimes no tained ascer- spots for spots wax time a generally are protected by been Near from by are observations 1 1 years. quite of weeks be to seen being easily visible smoked glass the about number of reached or a venient con- again will spots the about end and 1893, steadily diminish end of and increase of the reach present another 1904. telescope a of Sun-spots " about be will they about Hence of occurred that when century, in fog. minimum a side the magnitude numerous, eye, the when are of the occur of occur centuries, maximum maximum last spots times. two and may at London each on latitude all at day, large and every south sun-spots. than disc the spots 9 ; spots Fig. high period a minimum, that number the that rarely I., p. 75). equator. more over 35^ a the to near 5^ to in as have to appear that one Journal or observations quite apparent in drawn are and about it is very and equator, fact the north Vol. Continued " revealed one of Astronomy^ Association, ZOnea have surface 37 Atlas Astronomical sun-spot sun's axis (see BM'a discs British of the SUN. sun-spots on is not every to be condemned occasion that it is if it fails applied to to the sun. Eclipses present us spectacles of of the with one that can extremely is not to be taken to the rare sun. These of the be conceived. of that the earth when Unfortunately, at our phenomena, magnificent though most occurrence expected ends " any modest to total, fleeting they given place, and instrument observe total as will are it be eclipses,a POPULAR 38 TELESCOPIC passing reference however, that visible in will be there be in seen sujQices. be total 29th, then and that it will 1896, 9, It Japan. total a state, to Aug. on Siberia, 1927, and country, interest eclipse Zembla, June of be may a Nova until this It will Norway, not ASTRONOMY. last only will eclipse for few a seconds. Partial common the The usual the disc, its perhaps ThQ forcibly eclipses the supposed are tharii there going on, surface. could is sun be, to spots the that it is a grand indicated as us our nothing turns phenomenon. body black across the sun's spots which lie along moon's edge such on furnish on be will very occasions. of particulars is it the inclined an varying would instrument ! over in demonstrate that body change the to easy scattered cyclical more scope tele- sliding the immaculate by the intensely the telescope, not little year. indiscriminately not Surely teach simple a the observer the comparatively our of one will during seen with Thus, the diary or be to of upon almanac Any by ruggedness impressed interest gradually one of are occasions taken, watched eclipsing path. that be may the to being precautions moon such on add materially however, sun, and occurrence, will of of eclipses the amount be it once was axis, that his disc, the and disturbances of spotted justified if it CHAPTER V. THE An interesting satellite is which have the moon." but of the in the which moon that of it the interest Even a detail, construction of and great a their ating fascin- most make to views standing Notwith- world," the awaited always 20 of of the is about 30 or powers many lose turn re- with telescope. of with man aid. its in " beautiful '^dead is our patches while the by a a power the worth of quarter possessing magnifying is sake called first to of obtained often so anyone of amount is the be may moon by for only it the patches one and dark in larger alone eye belief remains heavens, if telescope naked various popular these moon the. the showing the to Telescopically, objects small To " object, rise given prominence, a study. beautiful a MOON. reveals from 40 a the 100, to formations lunar vast be can investigated. The from distance The round while moon's the moon its fying magni- a the happens us, As we that " earth distance according see the full moon moon, the to half turns this moon, on is sun how its is month, a once towards turned and time, to the is which one any so Hence diminish appearances. revolving presented It to appear miles, 2,000 miles. 240,000 nearly will varying hemisphere at 60 moon miles. 4,000 body, the is us of power to of diameter a dark the only illuminated is hemisphere or axis other in phases. the same POPULAR 40 that time it the than 7", and W. The effects near the edge detected and there in the nature by continuous of the peaks various be to is sun the on of from to employed, illumination the again us. appear At setting irregular of before observed sequently, Conance appear- the higher the valleys The when " by of of scarcely dark the these larger have must of relief nator termi- the the noticed disc the old is " part of the earth to on times, owing than dark to ones to moon the the of soon the in when necessary that feebly visible, moon especially noticeable it is the reflected whole is and of is best appearance This and darkness. in out Along conspicuous bright points very Everyone " sunlight objects as ary bound- to the it cuts. some time full. near them. the arms. to some appear moon rise moon's for features Earth-sllilie. giving telescope ; some falling almost are very the light standing far a views at full. which moon presents with lunar the ascertained half, moon, sunbeams the that so it is full differently near is not moon be uneven general given name and hardly be best it is more apparent very only when if before of terminator thus is not new the points illuminated and when the us the when is the that ; so most The can observed rising are illumination, This darkness viewed of the after be " moon are rings obtained sented pre- 8" E. could to Though only can about measurements. markings observations. full beneath, is without libra- " varying of indeed of are when and conditions the most disc, changes different horizontally or the small the see sometimes are angles, never appears the if after moon naturally light and line the always we of displacement a these terminator. of this of middle features The of that so consequence surface moon of the is also of the true In poles of the rugged under earth, slightly different at us ASTRONOMY. the face. same tions," however, to round goes the nearly very TELESCOPIC telescope a add, fact and that exactly this that is due moon, new the to the back bright same THE of size, the bright crescent circle larger diameter of The to the of water, the Seas." " naked and the have we of "coast-lines" the separately of "ay named. these the be to erroneous, retained. of number Sinus the attract tracts Thus ""c.,while latter, the likely to is most Colours, a visible are represent Imbrium, certain a Among to conveniently Mare to part. known now is still Crisium, Mare belong to appears darker the is this (maria) sea moon formerly imagined though " " name 41 great dusky patches which were eye the than The " MOON, along bays are Iridum, attention or of the beginner {see Fig. 10). Tlie first glance full, will near circular called greatly in ones are ones Walled are of these classes the Ring as a craters balloon. and similar in and but The Mountains, similar of recognised. are Craters^ as shape resemble as much 100, 50 as that so miles the so- to the in their ring teriors in- in diameter, scale of these that of their than greater smaller take ones science, such named of many their of in the learning a most Sketch to Map from times, of the half-hour. and these on such men as the of Foucault. craters Moon after of many modern more striking recognise pleasant past named Kepler, "fec.,while names the been of Schiaparelli,Lockyer, as forty have philosophers Copernicus, occupy three formations and astronomers process appear much is Archimedes, and number from would not analogues. larger Nearly immense an it be seas." " than more features terrestrial noted of shallower, craters are remarkable classed of the of the some size, and much floors Several they as PlaitiSy though are the The Plains." telescope,if a presence distinguished are mountains, while the volcanoes smaller larger with moon Walled ellipticalcavities, closely resembling or vary The the at reveal of terrestrial They and Mountains, Ring Craters, are represented (Fig. 10), the If further moon and the itself will identifications rOFVLAB TELESCOPIC AGRONOMY. POPULAR 44 TELESCOPIC 11. Fia. and moon, an that Atlas 115 miles. is is by Mountain earth, their lunar so on. in our in most are Four sketch identifying imposing craters, Plato working 60 found on their find of the the map, and them when is the the near added be and Ptolemy lunar craters this but action, is at analogues, Apennines, observer the Apennines, familiar will so that Mont ranges have with on Blanc, are no terminator. which, on mostly These moon. bling resem- ranges, are conspicuous more the To size. may miles, that we terrestrial the it mountain- which the Alps, in hypothesis. few A " with from we the of volcanic those be to names map results Ranges. somewhat of across, convenient a reduction generally agreed the really represent all events miles 55 Shadows. apparent scale the means no Lunar " consequent of idea give It the ASTRONOMY, take our and indicated difficulty By the the far craters the in THE the immediate when seen reach a about of height The Bills of the with 2-inch a Mare Rays streaks. or Near " reveals particularly noticeable. a,lmost give Tycho as a mountains far the one pole. The Kepler. Another when passes straight, and known, and may " southern part without of full moon, the streaks, or one Tycho, being crater that conspicuous so even meridians they radiating is centre immense the from crater tracts, through interruption. apparent So satisfactory explanation. the " the sun, through Like dark other earth casts this, there bodies in the shadow, a is and eclipse an of moon. it is very Although lunar eclipse,such visible, even red taken faint of to to courses the During phenomena the be of rays occultations the close darkness, to the moon the of very remains with light which traversing comparative seen not mostly moon after observing are watch to totality,shining during light,due their interesting The importance. of of over Moon. of moon are pass without neighbourhood a the ance appear- Hyginus rays important rays of the Eclipses the from These valleys, remain the the are of time bright impression long or they Cleft the certain apparently radiating system, little a into have It lies in the telescope. the striking. very of these the seen curve sometimes " bouring neigh- Vaporum. opera-glass "an of them conspicuous be may features 1,000 the ridge bordering and is are than of magnificent lunar which More bent. most seen These " curved this parts they some level the terminator excavations, sometimes be the on clefts. or of of ; in moon beautiful, very magnificent picture a above The projection when "darkness the is also half feet 20,000 Imbrium. Iridum later. after day a 45 form neighbourhood, Mare Sinus MOON, the the of on a have earth's great very tific scien- feebly dull, coppery- been bent out atmosphere. opportunity stars of progress which ordinary may are be too occasions. POPULAR 46 almanac Any moon will be may some When ation of Stars. of the it passes in front be may the be may for out which the the moon It the There size would of visible by a limb drawn been with even with of will for than details made. new accompanies the have other Reference map, and requirements some of to of a vations obser- such of the times of already be lead a of power lunar 80 what The the added that to the Mr. those been Elger's which book who the search has sufficientlycomprehensive as of to reference the made as charm observer if 100. or of scenery made well of volume whole been as to moon telescope, especially bear the the on fraction mere which to beginners experience. look to demonstrations the aperture. those is map gives disappearance objects 2-inch a this now may of records of are inevitably has it the the descriptions subject, however, the on desiring value difficultyin fillinga telescope or brighter stars, those of the good enough no eastern occur the the to atmosphere. has be of one sequence con- Almanac scientific is In the on instantaneous that be this The occult- the eya will by space. relatively place exactness understood object-glass naked occultations eclipsing or people Whitaker's The moon's observed be take " planet, or the consulted the occur. attention which the is without be must star motion limb. of upon the at that can they stars the round journey which stars reappearances phenonema. depends at will conveniently these of with the monthly occulting " eastward while particulars its bright a even right-hand or reliable of moon's limb, western and the In " myriads disappearances left-hand of eclipses which on constantly observed of stars, is moon other or dates expected. the earth, the give Occultations the ASTRONOMY. TELESCOPIC to meet already CHAPTER VI. PLANETS. THE How besides the larger earth than Venus, of the and others The and Neptune, "asteroids," near have the since the to and 400 distant or of so sun, worlds small planets," minor " or known nearest dim are Mercury, been being removed. them smaller. are Saturn, bodies of some ; their in other are dwell first-named the farthest last relatively ; Circling " there sun, we and Jupiter, times Uranus the planet, own Mars, planets. which on our pre-historic and round orbits respective the recognise to but modem are discoveries. in Beginners the mere In the first respect of their to the leaving is never rising by its radiance. all when ruddy and far the they the is When one sun, while Saturn become 47 the Jupiter again, by accustomed for sky some with his that may is tinguished dis- are by each fact the by again, from so. ones, positions evening by Mars, and has their distinguished are setting. appearance, closely the in considerations, from sun bodies not stars Jupiter, and is principal the watched change to other from required this the only if Venus telescopic very and but planets, to apt are knowledge body a seen stars. brilliancy; out as be the consider we light, will they from great of distinguished are steadiness nights if place, astronomy considerable some identification for they is of study out-door there that imagine the their other, Venus be even distinguished steady to the yellow use of a there star map, the planets, almanac. a is and only, can if the which particulars it lies. declination student The of planets The observer must the of will planets stars that be star map, and the be is one of the at to heavens. and rising bodies. their in movements, distances such if, for ; and satellites it must not^ newly-discovered fifth with seeing the connection, the within like case the in in this that, look will and enable heavenly in mind near will times approach stars that imagined the stars 20) useful very other or bear should such example, is also sometimes the the morning ascension right page on determine to the giving the to as corresponding place the of the setting found the in or an whether indicate once evening, place Orrery used be may be its exact Philips^ Patent and will at planets (see it in recognise once the table the plot to in with conjunction in will this seen difficultyin recognising any used be map to be to be longer no Reference planet ASTRONOMY, TELESCOPIC POPULAR 48 Jupiter, satellite. Mercury. that this planet those by This to observed before its in the at The that three for on and it is said parture de- maximum after sunset the or in sun furthest in be side other that so When to be only can precedes sky. the on it hours least it is at eastern it is said to elongation. western of revolution during times telescopes. its or the furthest when 2 side, eastern except degrees removed, it follows as across the mounted At 28 only searching country, because but than movement sun this brilliancy,as dawn. more sunrise, according the of or it is sun visible never elongation, be of lack twilight the in equatorially first-magnitude star, a apparent from all at seen with account on from it is be can careful after usually only is provided is not equal It " a year a the planet it is three "morning times star." of its orbit, however, round an On it does the " sun evening account not is rapid, so star of always " the reach and centricity ec- the distance angular same that be it cannot In small from derived astronomy it owes for its To these minutes, pass a transit of in front of the spot, which, be seen The or about 1895. with planet the June of almost indispensable or opera an in will when the planet visible of to low as of the ' N. a that diameter, in it us. the that will of 22^ from Sun. 12. Nearly 27" from Sun. 189^. Apr. 28. Nearly 21*" from Sun. Aug. 26. 27" the eastern a as naked eye, to circular can easily 2J. as power dark seen for observation on : " Jupiter. 16. from is planet Sun, in Gemini. from Sun, other remember following days 24" Nearly the from Sep. to appears 25** May it is nearest the situated favourably evenings 5. when by sunlight. Mercury Mercury, not be of arc, and moon. telescope a 3,000 miles, degree a 1. Oct are occasions these seconds. sun, though half O'^ 47 There to near means when 8. 1896. On should one illuminated body the phases During whom to sky the seconds 5 seconds, about like on of is about from values, 1,800 or dark a 13 to each are moon planet varies diameter appreciate Being put of the us, is, 30 indeed opera-glass is from and sun readily by senger Mes- " alL part a swift the be to Copernicus, it at saw of features no Mercury. apparent is farthest never that perhaps, Jupiter. or, diameter real The of so elongations. satisfaction glimpse a for it is said pretty field-glass. An searching planet presents planet occupies found be all the at certainly great much, so the times may is Gods," planet Venus, the this elongations, the at sun observed merely catching of the At the well equally there but interest, from telescopes 49 PLANETS, THE but rather low. Sun. " elongations " besides those TELESCOPIC POPULAR 60 stated, low but altitude of Venus. revolving as of its in noting sight and the the sun, do not disc, planet small half daylight, a to the a moon to its us, show The the the of it time days any is very consequence A magnifying crescent from is from full of smallest. which are Occasionally the means will phase Venus in of appearance size to our greatest removed naked sunlight eye with the pointing full, a ; nearly the of varying its diameter apparent arc. the telescope. seen that moon apparent visible For direction. or when be 2004. then the on of conjunction," is full across Transit At sun, towards pass 8, is farthest be to are Venus in but phase few there proper of it the 2-inch easily may the its a June as line same the "inferior markings of range to as and planet delicate angular 57 seconds show while and earth, the from presented, diameter The of from well as is turned effective. most bright enough in instrument this difficulty the happens until crescent, a be telescope, if small bility possi- account on size in us, known distances the to of Venus again consequently, is it see any little be apparent it after as when quite beyond its side dark and certain planet in nearest occur will occur are we by never should it, unless not is when, There the planet that so sun, can there changes appears moon and interior an unsatisfactory object very phenomenon angular obviously in a the a telescope apparent the star, and When before weeks the earth see will ; this some us, is great the we Venus a and phases. as sun's the the great brilliancy,but varying us, is of consequence midnight. Telescopically it of Venus evening or it at see its Mercury, been planet. between morning a in the Like " omitted have these ASTRONOMY, but power same as distance from 11 suffices to ranges of power when 20 gibbous, of about sun is 60 that is like the required distinctly. of revolution round the longer than that 52 POPULAR It be may than added lialf that Mars will 1896, and well (Map to of the from 4) five heavens the readily With In the and the the December 10, from us in Taurus recognisea it will be and west^ stars, if watched. i/^ seen again for four be to subject is which be be seen on one two on each through eclipsed. is the real are a of the side It shadow Sometimes 60 or of on in our seeing belts, and the with belts large is to seen highly probable Jupiter, of account on in planet different ever-varying aspect, the of the so in but it or is are passing it it is when of the satellites times other because front they the Frequently on. planet, pass at periods, planet's equator, all planet, occulted, they the Sometimes that the of plane belts. reason of cloud seems of surface side, and therefore 40 observed the or sacrifice cloud When the an the of 80 atmosphere. from parallel to and disc. round present of principal two his in invisible, for planet, the see removed far small a difficultyis experienced no frequent changes. satellites markings, power without power structure revolve they As his satellites magnifying the the finer clouds dense brightness, with principal Jupiter with even never we of some observation to on satellites, the the size and of interest. employed telescopes, of four his instrument, four of its great itself lends large ellipticity of be be towards object-glass a but home-made may will character addition, be definition, will more is, in distance a 1895, onwards, consequence 2-inch a may never until san, great east^ then never-failing source the too at relatively to In " telescope. the the to that opposition," " planet conspicuous Jupiter that is little Mars months. the the be The east, Jupiter. 100 in be September, the of earth. it will first to ASTRONOMY. diameter the again observed. towards and the not then move, or that of opposite part be TELESCOPIC there one may behind is said the passing to planet, be and THE instruments good with disc, especiallyif such at times tracks dark a be may their 53 PLANETS. along lie transit to seen is shadow the representing spot belts dark of the one the across ; sionally occa- observed. fifth,and A of the any Lick small very others, discovered was in telescope satellite,nearer but 1892, Barnard Prof. by is invisible this than Jupiter to with the but the all in largest telescopes. four The known usually Our of the phenomena be can observed In this of the is of 1897. Feb. 23. he the This when to which on they will observer find the with sees remember of diameter the Jupiter marking one is scale about observe can size. observed near constellation the In planet the following Saturn's ring succeed in is of one the (Map 3). Leo (Map 3). can is not finest times Even a recognising least at myth, the and the in objects instruments. observer " Cancer " adequate with seen telescope, the may the before. important " " " of " 24. modest dates actually he smallest best the by known : Jan. Saitum. care the of order particulars the years The will be 1896. that it is considerable very planet heavens printed that and what in are Callisto, respectively. all the country, observed. opposition our and so for compare again, miles, really of The to case, object 80,000 this also are includes satellites made predictions and Whitaker in interesting they Ganymede, friend good but Galileo by proceed which numbers, planet, lo, Europa, names it the discovered Jupiter their by from distance of satellites with self satisfy himwith principal a little of features planet. A 2-inch ring. power of 30 telescope With a to appears will that power of 40 about be give it is clear the minimum indications clearly visible, and on of a the 60-100, 54 with good a line divides Cassini's keen-sighted on belts of surface Jupiter ; the on but must changes in good, a distinguish the resembling the he has ceeded suc- shadow cast text-books most to of " remembered be that of consequence the with compared be " it very the telescope, familiar Saturn should astronomy so-called ring. of drawing A the that states 2-inch a to itself, planet dark the " is able be observer one with seeing, the parts definition also of and two the may the ball the into When visible render even ring observer in by the division. belts will object-glass, which ASTRONOMY. TELESCOPIC POPULAR the telescopic of inclination the of aspect the view, the ring of axis the planet. Of the within from Like is it only appears and useful to but, Jupiter, opposition, near This as the and is owing star-like a Saturn our need remaining small be following the best to Saturn. observed notes when of these of interest dates beginner. In 1896, May 6. In 1897, May 17. In Libra, Map " planets instrument, made. be the as distance greater companion can comes large as its planet, which one nearly to . The only " 2-inch. a the is name reality, in Mars be may of Mars us, by " range planet it ^Titan brightest the wonderful this attending satellites eight so present that no no 2. " features further reference to in them CHAPTER VII. COMETS. Orbits of Comets. No the with examining objects. Sometimes universal attention, them revolve they of some their their in regular planets do mostly the " this when seen of the is it that is, they sun most are greatest. in short the are of the perihelion, Few of attain peri6ds brightness. 55 the for it out nearest than sun then which considerable are gated; elon- orbit orbit is been orbits planets, comets any have much the the much as planets ellipses of off luminary. our these to pay pass The unlike comets, suddenly, great point of forms the ones. point ances appear- system our closer distant periodic near the " much very the reason, is are the as " the whereas their of that elliptic into "perihelion to of one that afterwards sway believed of paths they brightness round and attraction at " aphelion," For belong now but us and the beyond " that sun speak, them. shown make upon ful power- upon having come to most sun, thus orbits These far eccentric very so in so the of many have round and while bear to attract to the movements move comets parabolic their to the by brought orbits sun, ; in ellipses, space, the diverted of of of some the as the depths Hence in others to respects difficulty of lost remarkable enough 1882, apparent be these and be hyperbolas. or the into 1858 with of regularly, parabolas bright are can travel them they in which instruments Observations any perceived only are of telescope as should opportunity " is called. are that at only their revolve degree Where in seeing case of them can three and four or its be such Mechanic, "c., will The The a tail no when When be at The be at The " only as even its will of is a star-like somewhat this opportunity The more point is half the in the the the structures will of no observing numerous the " coma, of map, and comet is to of some have a of interest have comets small, are called centre by of them of into of or head and times some- " detail. interesting a an of luminous prove class star is, undoubtedly, of which layers project doubt readily comets Sometimes, surrounded fan-like and position be This of amount the nucleus phenomena comet resembling times, jets or the a and telescope. considerable a sometimes from of a and particular hour. any tail tails,some of aid brightest part shows There the 6 ; determined. once tail. a the telescope. as many with seen The the English Ascension sky many present, from popular impression with but cordingly, Ac- daily papers map, place of the path, comet a comet in to star a star the on observation, a on part Comet. a of time if used large comets, with seen or and of Right will stars what it is like all. at the happen may its striking feature, though presenting nothing most two of true in of is that extent for comet of map predicted. of the the bright enough, stars parts comet of for observed been be then can occasionally some indicate surrounding has star a Observatory^ Nature^ Planisphere, further cases "ephemeris" The the directions possible to compute dates an evidently only is any such comet a particulars if way, found. that in becomes surrounding to It " corresponding place the relation this When even or of by finding In and as furnish will Declination in needed, obtains source this comets future on one some fainter the nights, it place Comets. for is essential. sort some look to the ASTRONOMY. TELESCOPIC POPULAR 66 the great the nucleus, series of envelopes onion ; at other proceed matter All coma. interest when such the occurs. small comets do not exhibit COMETS. such of their Continued of formation the the Not continue of its shine to Movement. rapid that suffice to the even show field for this from the is, in fact, position of often the The of to of ; and discover a of its character of Retiims the it relation distinguishing comet, this observer he Ascension great on stars. finding the of accuracy, the meridian which : be nishes fur- stars the himself Among be may nebulae fortunate quite Comet. Period 7J years. 7 " " " " " " D'Arrest's Swift's " 6i 5i the expected " Brooks's 1897. should make can the it from Comets." comets Faye*8 to tain cer- feature. Periodic following 1896. in if the by interesting periodic are of in mined deter- comparison way observe to is with requisite degree comet a means star-clusters enough of the be instrument. movement ready the Right will intervals at determined only possible the impossible transit a be to position the so regard happen noted relative can with comet be positions with it is sometimes with comet frequently telescope a may measurements, known comet a which this of the Declination This and When raicrometric the should time is with of position same purpose. accuracy, as the at it behind situated of comets stars the is lustre. observation conspicuous by and The it. the of comet a stars ; movement hour's an about undiminished The gradual the sun. thing parts of patches intensification the to various with " more the approach stages some reveal may the remarkable least transparency tail, and at faint as appear watching short a during nucleus telescopic details, and they simply careers luminosity. to of great variety 67 " " more to appear re- 1898. ASTRONOMY. TELESCOPIC POPULAR 68 Winiiecke's Period Comet. 5i Wolf's 7 " 1899. " 13| " found complete in " Halley's 76 " " A " Tuttle's " 1911. years. of history Remarkable and these Comets^ a other little Lynn.* * Stanford, price " 6d. book comets by Mr. will be W. T. POPULAR 60 of the sixth ; but to carry of the brighter than of the star a as in 100 to that round less 8th of 2-incll. should of the universe of stars in apparent collects and the equal the of this light show stars and its area greatly the on were as eye 2-inch is light as limit. reflection in nitude mag- power because the the the the only will O.G. be 100 on 11th mag. Owing to the " the our ideas proportion. become eye object-glass of the is the by pupil the to be i.e.,5 loss this mags, of lenses, however, one- that pupil, so of of area light more eye, nearly one-hundredth times than and instrument of the diameter we existence pupil object-glass divided with the of naked than of out really utilised, a telescope faint of the all to at object-glass. Hence, falls naked take we inch, star the If an 2-inch of the area pupil. fifth a the the invented, been ignorance This of amount also are seen heavenly bodies, visible not 7th is reckoned example, Stars never been have light-grasping to had the telescopes. larger a of would for of total in great majority found be magnitude a have, ment measure- 7*5. telescopes of the Millions amounts star a bright, it less Number remained have if understood star, it is rated mag. of may as and If " we stated star 6th a if that so Fractions that so Magnitudes a bright as in the employed now 2-5) times x on. so of, a than (i.e.,2*5 count are magnitudes, and mag., taken precision bright if 6*25 ; mag. of stellar times 2^ of star a itself 5 times multiplied by times 100 times be will sary neces- average that so 2^ really about This the reckoned ; is is numbers. Instruments of 2-5 that magnitude fainter. magnitude one considered it be is found fairlybe sixth notation telescopes,it been may particular magnitude any has this it goes, as have we It magnitude one far that now it further. first ASTRONOMY. So magnitude. still retained star TELESCOPIC that size lower of from a if all would than light by absorption the minimum THE visible magnitude With nights. In the well as of 2-inch little interest with in In on a numberless, and adds charm the to that out the the and Auriga, Sagitta, Aquila, cited be may When of view, they are Ooloured colours, stars of and j8 Pegasi, once enable a Cor. these little telescope. identified to patience : the will colour be pointed is specially Cygnus, of a in the Persei The deep required in which brighter Aldebaran, will maps red desired if it be be the to field for their the Among remarkable more stars to are observe pointing be can at the easily " H Cephei Mira ^ a Variable that almost and remarkable are Reference so sky (Chap. X.) clusters star as recognised. radiance, more Way Betelgeux, Antares, are be may together yellow. or of regions. stars Hydrse. Among are red tint of feeble mostly these, chiefly reddish Many " met the are neighbourhood closelygrouped very stars. deep the of constellations the distinguished are Milky be worthy brightnesses the particularly rich as stars a of of be to groups It as range may parts them. observing respect, and this in interesting in these, conditions. well some over the frequently telescope, such neighbourhood all stars groupings 14. are within come are great variety of there and 9*5, through the with alone clear very 10-inch atmospheric or "sweeping" on a individually the streams good night 10*5 with should ones, telescopically,they beautiful scrutiny. and 12*9, magnitude Although " is about favourable glass under fields. 61 hemisphere above or still fainter many Star it is celestial of stars 2-inch a 6-inch a northern 300,000 a with STARS. stars. periodic fluctuations variation is not very " Ceti (Map 1). ( 4). Virginis ( Herculis of Some in ( " " " 3). 2). the brilliancy ; great, and occurs stars in in are subject some periods cases measured to the POPULAR 62 days by The hours and the and greater, interest. glass in as " naked telescope less the be can few a the the variables, star j8 Lyrse (Map it has time and in from (Map 4) months), and will the during magnitude equal to six-hundred-fold difficultyin magnitude, of few years. 2nd of afterwards regularly until somewhat irregular, but its monthly in Companion to other surrounding stars. days, its maxima of cycle and during minimum 3*5, a variable this of 4*9, reckoned for observation From about at 9th 11 mum maxi- 10th or occasionally star star, corresponding There progress be may passed. may will it reaches when is (about star light. star maximum in which continuous a magnitude the nitude mag- of wonderful this of another. placed well the with 13 long-period a remains minima the 3*9, the period being to increase the fication identi- 4th to observation magnitude minimum identifying and the intervals at falls from the under of be a in light published through minimum, at ever, how- original brightness of are as little a next its compared goes is Mira a be principal one becomes must minimum secondary a this, the except it obtained be maxima two regains In 2) 4) when observed may period a to that so difficultyof the Particulars conveniently they magnitude, and 1 days, time. or field a invisible become magnitude, and hours, Observatory, changes 2nd three same Knowledge^ 6th or of increased. at than or opera longer period variables, Algol (Maps constant in nearly of case full period variables, an never essential,and is enormously near little a 5th a the very above rise is In of the short must is period, most, stars Many eye. at or, " the cases never of aid required which phenomena, of the is months. considerable a variation of range by of class of many case these the is measured over is ASTRONOMY. others of this the instrument the period extend In in ; observation necessarily no TELESCOPIC The fairly be to be the no 6 th observed period expected is in STABS, THE January and in nearly very distance d from Full line a from the as instructions with stars, will of New 8 of the variable of knowledge the monthly, ations, vari- Popular 1895. February, the is nearly at observation American times At It them. our the in 1897. Ceti, between systematic and StaiTS. through increasing January Astronomy, a the found be November, distance for view a and 1896, December, 63 world astronomical receives " a fresh star new or star no by of source are very only can of possessor observing is worth powerful good star if decline in that Nova map, of new form stars. an nearly it. all Usually they feeble so instruments. gratification some fortunately become fluctuations irregular and brilliancy. the last pocket of new 1892 with telescope. outfit no the more Obviously, of of in discovered was " knowledge the visible star Anderson, extended part where discovered been become find should Dr. a place a powerful will Aurigse, than and weeks most one its " instrument the the noting to so-called a immediately few a telescope astronomer, must discoverer in remarking amateur an seen star hemisphere northern in has directed are and small in rapid subsequent be new a especially visible, by a and in star, a exist, to world of appearance like observer, the in the known short-lived, they It looks painstaking telescopes in What previously the The in nova. was some that interest the the would-be a stellations, con- CHAPTER IX. DOUBLE Doubles and STABS. Binaries. It often which of single appear close two These there stars side, although, appear widely their that changes stars, or to Stars reference has Though the the Some others the colours companion will forming of In nearly a many equal usually are is in will the two movement called are doubles, much themselves stars evident apart quadruple. are planets binary which to made. it is stars of orbital optical the law between class latter the by really observations that so be same of distance from component wider the of would they may by two side appear suns continued them, that line same space, movements the them been enlargement, power, of distinguish two apparent joining the of part stars, the line indicated. stars, of in the in such clear is First, they together the it in that so Next, controls telescope. a appearances. another bound and nearly earth, from in courses; show is the and such very separated. together, gravitation be with stars, for to seen observed stars consist to seen are eye double causes from seen as close two happen may sight so-called be may naked when components the are the to that happens " that the the higher stars gravitational of magnitudes, pretty smaller than 64 magnifying the system double the the in appear similar. the telescope. triple; are stars and capable not are in In primary, the such others and ponents com- cases the very DOUBLE frequently has white bluish a Double-star telescopes, and reference. Castor of however, from the in with an In distance of of in earth to it has the stars from in a two miles measured than binary star, the of measure series that the sun between two a circle of too their be have been it not is a the the made likely themselves with content to stars from far removed distance an mean the components radius a from the Thus us. times angular separation of the be the angular million a foreshortening, to calculate from is about measures is found the two ; the components, on to with provide possible Castor for of micrometric it is not are corrected when pressed ex- involves aperture, would is correspond measurements to tance dis- size. they a double a connection in prepared are determined been distant more the permit selected apparent measurement inches two between if measurement, 3,600 micrometer a miles which of few a who of this case these symbol are The " form micrometer although expensive the of arc, of of those instrument the simplify matters, which stars process form many and the chapter in this components. of instruments that that To and Usually quoted, are them. to known best astronomers to conveniently objects. Burnham of double. are are the suitable purposes Majoris of such among The single degree. with reference, and two seconds telescope,but for of referred the some with suffice some already stars seen term of between between of be stars. eye Distance when Ursse catalogues known the Y in doubles naked use principal star and sufficientlyrefer ^ or a of names numbers Struve generally so such their by double ordinary having not catalogues 2 the complete are the Many " be to Thus indicated most whether colour, names. found are Others, 65 yellow. or named STABS. l"*b distance is the million determined as ; then of between the distance length times of the 7''*5 sun's POPULAR 66 distance. sun's This will distance. about of the To " the follows : times 38 nearly revolution double a this in the is case The central and W., The one. in as is of the as the expressed north the brighter position angles astronomical an necessary from the tion disposi- measure a direction and E., S., is angle the specify star, them joining them. 360", to be completely of line through 0" from of angle," i.e., the measured as to years. between "position taken found components of direction ASTRONOMY. period angles. the distance be The thousand a Position as TELESCOPIC by point being star reckoned are telescope they are " S W^/ol Fig. 12. As line in the with direction be careful E. of the of the movement must the to and W. across the confuse this star not a in the faint, as telescope the is usually two the is useful is not eye in cases wearied direction. wrong of 2-inch power between position angle is very searching Dividing distance of companion the of the horizontal. needless power sun, apparent beginner knowledge where by the the A of the of the is that field,and case Illustrating position angle. " telescope. stated components in terms of the " The dividing of the angular closest double POPULAR C8 in striking of TELESCOPIC small a ASTRONOMY, but telescope, included are for sake the completeness. The column idea some of observe the provided with 30 the when while lowest field lens used be in gives regard various numbers The recent rapid notes in as be rate. 60. well as position in changing, the case though of Judgment must the as a rule, be remarks by maps, the distance binaries worth also the of of or can of to and not, be column only 20, indicates situations angle of scarcely references the be column The indicating of sources, of to expect may power a will this weather. as brackets, measures obviously the to it observer instrument him removed, power a he the giving which those with seen is which if ; eye-piece, one attempting only double the give to with power particular any intended is "power" stars. from are values at must a very STABS. DOUBLE 69 o -S 00 .9 I 8 % o a" 8 a o s "* as o 0? 1 (X" 1| ;-) 49 0? o t s o o o a" a" I s ^ o o pq ^91 "^jt ^" tJ" O CO o C4 000 O "" ^ " CO 00 (N O "I COi-HC^^i-HC0C"l"l S,o 5"0" O 0000 O "1 CO o CO w i-H CO o C4 o t3 o o 00 00 a o o .a ;^ o5 o ^ 3^ . d) 1"4 _4J_S,J ^'^ ua^uaua ^ ^ "a w ^ o "3 " " V " " " " " " " " " ' " " Q? Q" ^^ gM " Q) " Q) " 4^ " Q) """""" """""" a 'g a "^ "=5 c :Q to d d a p4 04 04 ^ Sb bo "i'S " "J i-lO"C0 k55 C l".i .J .S ^ " : : Ui a "JJ ^ "^lOOr* Q0050^(MCO"^"0 CO t^ 00 O ASTRONOMY, TELESCOPIC POPULAR 70 43 O "s CO " S I o ^2 o "1o "2-^ ^S*c5*co S-^SS. g S "N S o C4 cc o o $4 CO "-"o O) CO "" CO -* ^SS "T^ 8 8 o CO S "-3 3 " OQ 8 CS O O o CO WO It-^-g 9 a 1^ CO i-H S5^ p3 .^ ,-H "0 !". CO eo 00 -^ CO CO C4 CO in ^ CO i -^ -'s^ "" ^ Od I-H ^ I ' 01 Od I-H CO CO ^ '^ g !$^ " I " ^ ' ' I i CO ^coiocococq^ o S I-H I-H ^ 6^ 4j" ^^^ o c^ O 00 oo lb osco .a : o .a t^ 6 " "5 II OQ 09 ^*2 S " s.g GQGQP ow fh "o ^"^ s^ o o" o ^ Oi ^- Cq "" QQ. a CO C^ "^ 01 }sj" "o i-i c5(nST"mSto "o b QQ.^ cococo Kf C CO "^ CO DOUBLE Double visible in the will each in made in in show II. the the 71 month." double corresponding preceding working The foregoing numbers the preparing Chapter of the of each in which month, column first assistance is visible stars table ing STARS, list. lists to follow- stars with This which will are those be reference of CHAPTER CLUSTERS STAB Naked is it closely very familiar there with is The the that the perhaps of one of the stellar one when viewed in even behold Gala.xy. Milky Way the the it. other in occur it eye "fire In is air is of defiled not features of as the but with smoke, the evening nebulous filmy a old small the of distribution these stars much greater naked stars but astronomers the distances is form of corresponds eye, of it the 9th to the those magnitude. 72 which of consist a According the Milky "Way, closely very comparatively than to seen enumeration. defying stars probably are aid optical investigations, to it towns advantage, to seen appears mist" large our " striking most smallest of recent an " the multitude this each " with of of or who very from group conspicuous, or naked the To appears all a stars part instrument, less is distant this impress where country, open luminosity scale Way rarely the of small but brighter form they aspect to example, sky. Milky sky. to fail cannot the the themselves group for of parts to immensely that our groupings, of but be on certain tend though doubt 20 In " Pleiades, even must little NEBULJE. stars magnificent glass, parts even and of Similar is The power a opera it together. The system. in that group other, is observed instance, well-known AND groupings. eye heavens X. 15th the with and magnitude, small ones are higher it as at in not the The of sweeping observing the afford student the' food besides, the Sidereal be, may reflection of the may there are of them of nearly the often exhibit the globular In of system much close " A table, with the the and very with be described many stars are close gether, to- large very consisting as clusters compressed very clusters hence are in shows these wards to- known as selection looking upon have been they as part of the a sidereal belongs. sun they only form to regularity. are abandoned, probability clusters some we and compact, so marked no clusters almost star quite not are stars now our of these telescope,but very is which to Many such in that universes with shown order, globular form, condensing less clusters the cases idea old distant cluster, but these seen Milky clusters. other The when only can or In brightness, These and centre, distribution the of cluster more a this to the different itself. Way "star-dust." much depth system star somewhat close, even so the and view immense an a order same telescopes, that so of Milky the in as of point one upon sometimes of From " clusters many solar our of stars. looked be of now Construction " length, breadth, its relation is the what Clusters. Way what give him, great problems the " will tracings, pleasure, and of the one on of astronomers minds larger system of Way, Milky stellar the amount 73 the across in variety Universe," and Star telescope vast a for the occupying the infinite NEBULAS. AND CLUSTERS STAB cases " of particulars where as appear clusters as within come to when of star the reach given and patches the in where a 2-inch stars component unresolved is of are of luminosity. appended they are to be seen. The drawn of to the earliest up more employ catalogue by Messier, and conspicuous the numbers since of in clusters this these Messier's and naturally objects, it nebulae includes is still catalogue for was most common purposes of reference. in " of is in the Messier's catalogue eye given the general, Most on " a of very will low the best named clusters clear facilitate 20 as nights, the these on search not included numbers in and nebulae, objects will 2-inch our revision a it is hoped for be them. obtained telescope. visible dimly are and that Dreyer. of views cluster and their by clusters Dr. by power, of the Clusters designated are that catalogue, Pegasus. catalogue, using Messier's in Catalogue Herschel's In 15 indicates Pegasi constellation General New by No. ASTRONOMY. M. 15 Thus, question occurs in TELESCOPIC POPULAR 74 that to the the naked directions it the POPULAR 76 NebulSB. TELESCOPIC It will " star clusters, when dim patches of sufficient power imagined that of into shows the require further nebulae impressed Canes, which, in nebula a a naked scrutinised the second The others and the Faint to his are observe one still very many Hence, This from whether clusters and difficultywill of comparison bright enough few with such a like one the on ance appear- which visible be to be can Nevertheless will this with profitably the telescopicdifference the student between form a valuable a be little image time rewarded not see at moves centred, once and a by to before found a little the everything the the keep looking if the moderate in appearance the beginner, eyes for from them. telescope rate patience at first easily observed. most difficultyto taken readily more following list,the the little some should some in to important most the does troscope spec- which said be telescope,puts very referred be The distinct can be cannot reading. are will ance appear- quite it telescope. present when they easilyresolved, cluster, and the may that so ; are precaution field,and details star nebulae moved to a lights for strong are a strated, demon- the on the comet. are observe nebulae and small 2-inch a himself supplement Of there is 2-inch a nebulae with and nebula or two eye, for be to after observer simply was distinguish that clusters. Praesepe,which Although may the on were whatsoever. before star or and there investigation the as of the time same it abundantly usually catalogued together. are cluster them time " to been power any of really nebulae are 3 with one nebulae " of telescopes nebulae, putting true many At clusters. has really exist, stars At as appear resolvability, with unable were It do resolved termed we compressed of signs no them. now that telescopes,will or be with are that clouds, resolved M. deal which however, be easily to in small little light with constituents. separate they with seen what clusters star easily understood be although they might ASTRONOMY, first across be the continuing of greater glance. STAB CLUSTERS AND NEBULJE, 77 Ymmm m 2yi inch I *i.^ diameter, " "" "" 3* *4. " ,, "" " for eye-piece. ' ' 2. DBSCMBED Glass. Object Achromatic focus Lens 3 AS nm. inch 30 I ,, TELESGOFB UP HAEINEf FOE MATERIALS I I a " "" "" Thin a Disc, Brass eye-piece. extra ,, "" "" inch i for Lens J " ,, "" "" "" "" hole with diameter, | for diameter inch eye-piece. 5. Thin Brass Disc, inch i with diameter, hole for diameter inch J eye-piece. extra ^ *6. Mache Paper Tube, inches 24 long Blacked diameter. inches 2} and inside. *7. of Set tube. draw t8. 9. Set of Dark 1 1. Screen Ink Glass for Complete for the viewing of tubes making glass cell, and Sun's the with parts, named. last brush. directly. sun without Telescope object eye-piece, internal blacking Projection for inside. Rollers for for Tubes Blacked Wooden 4 Bottle 10. 12. of Mache Paper 5 image. Stand, eye-piece one magnifying times. 13. Extra 14. Tripod Eye-piece, Telescope made 15. 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