We need only describe Orion and Canis Major, the principal groups. The former certainly constitutes the most glorious group, and it is visible to all the world, because the equinoctial passes through it.
Orion, as we have said, can be viewed from either hemisphere, and so can some others; but those marked with an asterisk in the foregoing list are not visible in the latitude of London.
Fig. 609.—Orion.
Orion is a very brilliant constellation, and contains two fine stars of the first magnitude, and some of the second. The former are Betelgeux and Rigel. Bellatrix is the third in order. The “belt” is formed of three bright stars, and the sword is visible as five stars just below. Canis Major possesses Sirius, a very fine star (the dog star). Canis Minor has two of the first and second magnitude, and Hydra has one of the first. The Southern Cross is a beautiful constellation, invisible in our latitude, but familiar to sailors in the Southern Seas.
The Stars’ Distance and Magnitude.
Fig. 610.—Polaris.
When we gaze up into the sky at night, we see the stars twinkling far away, and we may remark here that this twinkling of the stars is due to the atmosphere and the changes in its power of refraction, and of course the star’s light changes its direction. But if we ascend in a balloon into very high and rarefied strata of the air, we will find the twinkling less. We have given the number of the stars according to Flamstead, but the larger the telescope the greater will be the number of stars we shall see, numbers again being too far even for our perfected instruments.