Through Magic Glasses and Other Lectures

as they crowded round him on the college green, one e

the garden in summer, and looked up at those wondrous lights i

r walking across country on a winter's evening week after week, and looking all round the sky, that the glorious suns of heaven force you to take notice of them; and Orion becomes a companion with his seven brilliant stars and his magnificent nebula, which appears as a small pale blue patch, to eyes accustomed to look

long before other stars have conquered the twilight, and feast our eye upon his glorious white beams; and

. For as our earth turns daily on its axis, the stars appear to alter their position hour by hour, and in the same way as we travel yearly on our journey round the sun, they appear to move in the sky month by month. Yet with a little practice it is easy to recognise the principal stars, for, as it is our mo

after sunset. If you take your place at the window to-morrow night as the twilight fades

ne each l

ts golden

ar he was, you would not doubt long, for in a little while two beautiful stars start into view above him more to the west, and between them three smaller ones in a close row, forming the cross in the constellation of Orion, which is always very easy to recognise. Now the three stars of Orion's belt which make the short piece of the cross always point to Sirius, w

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een when looking south in Ma

of misty, tiny stars called the "Milky Way" which passes over his arm and club. Yet the figure of the huntsman is very diffi

e Frontispiece). With your telescopes it looks very small indeed, for only the central and brightest part is seen. Really, however, it is so widespread that our whole solar system is as nothing compared to it. But even your telescope

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of Orion, wi

r Pro

different, for the spectroscope tells us that the mist passes over it, so that it is either behind or in the nebula. Moreover, this star is very interesting, for it is not really one star, but six arranged in a group (see Fig. 56). You can

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onis, in the nebula

w myriads of minute stars which had never been seen before. "Then," you will say, "it is after all only a cluster of stars too small for our telescopes to distinguish." Wait a bit; it is always dangerous to draw ha

the mist is spread out it gives, not a continuous band of colour such as would be given by stars, but faint coloured lines on a dark ground (see Fig. 57). Such lines as these we have already learnt are always given by gases, and the particular bright

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a-spe

spec

howing bright lines, with sun

in March 1881 Mr. Common got a still better effect, and last year Mr. Isaac Roberts succeeded in taking the most perfect and beautiful photograph[1] yet obtained, in which the true beauty of this wonderful mist stands out clearly. I have marked on the edge of our copy two points θ and θ′, and if you follow out straight lines from these points till they meet, you will arrive at the spot where the mul

clusters of very minute stars, astronomers thought that Laplace's teaching had been wrong. But now the spectroscope has revealed to us glowing gas actually filling large spaces in the sky, and every year accurate observations and experiments tell us more and more about these marvellous distant mists. Some day, though perhaps not w

re him that well-known cluster, the Pleiades, which we reach by continuing the curve westwards and upwards. Stop to look at this cluster through your telescopes, for it will delight you; even with the naked eye you can count from six to ten stars in it, and an opera-glass will show about thirty, though they are so scatte

ou something about Castor, the one nearest to Capella. If you look at Castor through your telescopes, some of you may possibly guess that it is really two stars, but you will have to look through mine to see it clearly. These two stars have been watched carefully for many years, and there is now no doubt that one of them is moving slowly round

rder which reigns in our small group of planets is in action billions of miles away among distant suns, so that they are held together and move round each other as our earth moves round our sun. I will repeat to you what Sir R. Ball, the Astronomer-Royal of Ireland, says about this, for his words have remained in my mind ever since I read them, and I should like them to linger in yours till you are old enough to

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een when looking north in Ma

d to-night, so we will pass through Leo, and turning northwards, look high up in the north-east (Fig. 58), where "Charles's Wain" stretches far across the sky. I need not point this out to you, for every country lad knows and delights in it. You could not have seen it in the twilight when Sirius first shone out, for these stars are not so powerful as he is. But they come out very soon after him, and when once fairly bright, the four stars which form the waggon, wider at the top than

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s's Wain, and also the small binary star ξ in

by the second horse," and by astronomers "Alcor." Even in your small telescopes you can see that Jack or Alcor is not so close as he appears to the naked eye, but a long way off from the horse, while in my telescope you will fi

r you must remember that your telescope makes objects appear upside down, a

tronomers have observed more than one revolution since powerful telescopes were invented. You will have to look in my telescope to see the two stars divided, but you can make an interesting observation for yourselves by comparing the light of this binary star with the light of Castor, for Castor is such an immense distance f

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showing the directions in which t

heavens caused by our own movements, they have each also a real motion and are travelling in space, though they are so inconceivably far off that we do not notice it. It has now been proved, by very accurate observations with powerful instruments, that three of the stars forming the waggon and the two horses nearest to it,

the naked eye. You may, if your eye is keen, be able to count twelve. Now take an opera-glass and the twelve become two hundred. With your telescopes they will increase again in number. In my telescope upstairs the two hun

y perhaps, with the naked eye, have in view about 3000 stars; then consider that a powerful telescope can multiply these by thousands upon thousands, so that we can reckon about 20,000,000 where you see only 3000. If you add to these

ars invisible in the most powerful telescope, make them print their image on the photographic plate, and at once our numbers are so enormously in

e. Indeed these two stars are called "the Pointers," because a line prolonged onwards from them will, with a very slight curve, bring us to the "Pole-star" (see Fig. 58). This star, though not one of the largest, is important, because it is very near that spot in the sky towards which the North Pole of our eart

ver you are in the northern hemisphere, if you once note a certain tree, or chimney, or steeple which points upwards to the Pole-star, it wi

cial name, but only part of the "Little Bear." Those two hind stars of the tiny waggon, which are so much the brightest, are cal

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, and the heavenly bodies which

idespread W written in the sky by five large stars; the second V of the W has rather a long

find them. I want to use them to-night chiefly as guides to find two remarkable objects which I hope you will look at again and again. The first is a small round misty patch not easy to see, but which you will find by following out the second stroke of the first V of the W. Beginning at the top, and following the line to the point of the V, continue on across the sky, and then search with your telescope till you catch a glimpse of th

dromeda, and has sometimes been mistaken for a comet (Figs. 58 and 61). You will, however, be disappointed when you look through the telescope, for it will still only appear a mist, and you will be able to make nothing of it, except that instead of being of an irregular shape like Orion, it is elliptical; and in

o be at the red end. Now, since gases give only bright lines, this nebula cannot be entirely gaseous. Then it must be made of stars too far off to see? If so, it is very strange that though it is so dense and bright in some parts, and so sprea

t, but if you come to me about nine o'clock to-morrow evening I will show you that it is growing dim, and if we had patience to watch through the night we should find, three or four hours later still, that it looks like one of the smaller stars. Then it will begin to brighten again, and in four hours more will be as bright as at first. It will remai

lliant bluish-white star a little to the east of this line. This is Vega, one of the brightest stars in the heavens except Sirius. It had not risen in the earlier part of the evening,

m easily, and a powerful telescope tells a wonderful story, for it reveals that each of these two stars is again composed of two stars, so that η Lyr? (Fig. 62) is really a double-double star. There is no doubt that each pair is a binary star, that is, the two stars move round each other very slowly, and possibly both pai

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revolves, and the couples probably also

coloured, but they do not by any means all give out the same kind of light. Our sun is yellow, and so are the Pole-star and Pollux; but Sirius, Vega, and Regulus are dazzling white or bluish-white, Arcturus is a yellowish-white, Aldebaran is a bright

te

D DOUBL

e other a pale green, while in powerful telescopes the green one splits again into two (Plate II.) Then again, η Cassiope?, the sixth star lying between the two large ones in the second V of Cassiopeia, divides into a yellow star and a small rich purple one, and δ Geminorum, a bright star not far from Pollux in the constellation Gemini, is composed of a la

e tailboard of Charles's Waggon and the second horse Mizar. Rigel in Orion, and the two outer stars of the belt, α Herculis, which will rise later

te experiments, Dr. Huggins has shown that the light of all stars is sifted before it comes to us, just as the light of our sun is; and those rays which are least cut off play most stro

many rays are in this way cut off; so that when we spread out his light in a long spectrum there are dark lines or spaces where no light falls.[6] Now in sunlight these

ound the star, and thus their particular colours are dimmed, leaving the other colour or colours more vivid. In red stars, for example, the yellow, blue, and green parts of the spectrum are much lined while the red end is strong an

n to use the telescope fairly, you will often not know how to get a clear view with it. Still, you may learn a great deal, and before we go in I want to put a thought into your minds which will make astronomy still more interesting. We have seen that the stronger our telescopes the more stars, star-clusters, and nebul? we see, an

ersity, when suddenly the son, who was looking at Sirius, exclaimed, "Why, father, the star has a companion!" And so it was. The powerful telesc

re from our sun, and moves round him in about forty-nine years. It is seven times as heavy as ou

ch is close to it, shines brightest of any star in the heavens, how many more bodies must there be which we sha

laws, we can scarcely help speculating whether round these glorious suns, worlds of some kind may not be moving. If so, and there ar

at those twinkling specks become as suggestive as the faint lights of a great fleet far out at sea, which tell us of mighty ships, together with frigates and gunboats, full of living beings, though we cannot see them, nor even guess what they may be like. How insignifi

brightness, estimate their weight, and discern their movements. As we gaze into the depths of the starlit sky, and travel onwards and onwards in imagination to those distant stars which photography alone reveals to us, do not o

ion. The star-halo at the top of the plate is caused by diffractio

tory of t

sickle alone comes

, it has been accidentally

n most kindly drawn to scale and colour

in Table of Sp