You will find it an interesting occupation to make for yourself maps of small parts of the heavens. First copy out the chief stars in their proper places from the star atlas, and then fill in the smaller stars with your own observations. Try first on some limited region of the heavens; take the figure of Cassiopeia, for instance, or the Square of Pegasus, and see if you can produce a fair representation of those groups by marking in the stars that your instrument will show you; or take the Pleiades and make a tracing of the principal stars of the group from the sketch that we have given ([Fig. 89]), then take an opera-glass and fill in as carefully as you can all that it will show. I can assure you that you will find a little definite work of this kind full of interest and instruction.

But I hope you will desire to advance further in the study of the heavens. It is to be remembered that with even the most moderate instruments there is much to be done. Many comets have been detected, and many planets have been discovered, by the use of telescopes so small that they could be easily carried out from the house for the evening’s work and brought back again after the observations were over.

It remains for me to add a few words which will help you in finding the planets. It is, of course, impossible to represent such objects as Jupiter, Saturn, Venus, Mars, and Mercury on maps of the heavens, because these bodies are constantly moving about, and if their places were right to-day they would be wrong to-morrow. The almanac will be necessary for you here. You must find out by its help what planets are visible and in what part of the sky they are placed. Then you will have to compare your maps with the heavens, and when you find a bright star-like body that is not shown on your maps you may conclude at once that it is the planet. Although these objects are so star-like to the unaided eye, yet the resemblance is at once dispelled when we use a telescope. The star is only a bright point of light and white, the planet shows a visible shape. This is, at least, the case with the five planets I have named; for there are others, such as Uranus and Neptune, which are too far to be much more than star-like points in ordinary telescopes. The minor planets would not interest you.

I hope that the reading of Star-land will, at all events, induce you to make a beginning of the study of the heavens, if you have not already done so. If you have the advantage of a telescope, so much the better; but, if this is impossible, make the best use of your own eyes. Do not put it off or wait till you get some one to teach you. If it be clear this very night, go out and find the Great Bear and the Pole Star, and as many of the other constellations as you can, and at once commence your career as an astronomer.

TABLE OF USEFUL ASTRONOMICAL FACTS.

The sun’s mean distance from the earth is 92,700,000 miles; his diameter is 865,000 miles, and he rotates in a period between 25 and 26 days.

The moon’s mean distance from the earth is 238,000 miles; the diameter of the moon is 2160 miles, and the time of revolution round the earth is 27.322 days.

THE PLANETS.

Mean Distance
from the Sun
in Millions
of Miles.		Periodic Time
of Revolution
in Days.		Diameter
of Planet
in Miles.		Axial Rotation.
Hrs.Mins.Secs.
Mercury 35.9 87.969 2,992Uncertain.
Venus 67.0 224.70 7,660Uncertain.
Earth 92.7 365.26 7,9182356 4.09
Mars 141 686.98 4,200243722.7
Jupiter 482 4,332.6 85,000 955—
Saturn 884 10,759 71,000101423.8
Uranus1,780 30,687 31,700Unknown.
Neptune2,780 60,127 34,500Unknown.