TO KNOW THE STARRY HEAVENS 
the northeast corner, is a variable star 
whose magnitude changes between 1.0 
and 1.4. The star at the northwest cor- 
ner is of 1.7 magnitude. The stars at 
the southeastern and southwestern cor- 
ners are respectively of 2.2 and 0.3 
magnitudes. The three stars in the 
middle of the constellation commonly 
known as the belt of Orion are from 
east to west of 2.0, 1.8 and 2.5 magni- 
tudes respectively. It may thus be 
noted that the average magnitude of 
the seven bright stars in Ursa Major is 
2.3. while the average magnitude of the 
seven in Orion is 1.7. Orion has two 
stars brighter than any in Ursa Major 
and a third equal in brightness to the 
brightest of Ursa Major. It is thus 
seen that Orion exceeds Ursa Major in 
brightness as it does all other constel- 
lations. 
Next we may consider the positions 
of the constellation. Ursa Major is a 
North Polar constellation. Two of its 
stars, “the pointers,” are usually used 
to locate the north star and the pole. 
As a polar constellation it is above the 
horizon at all times for most northern 
observers. For observers north of 
forty degrees north latitude none of the 
seven stars ever set. We must go as 
far south as twenty-eight degrees north 
latitude before the whole seven will be 
found to set. This fact that the stars 
are nearly always visible in our lati- 
studes helps greatly in making the con- 
stellation familiar to us. But observers 
south of twenty-eight degrees south 
latitude never see some of the stars in 
the dipper. What is our gain is their 
loss. 
Orion on the other hand is an equa- 
torial constellation. The equator passes 
through the middle of it. For this rea- 
son it can be seen only half of the time 
at any place on the earth, but there is 
no place except in the uninhabited re- 
gions near the poles where the whole 
constellation cannot be seen. Orion is 
at its best at the equator, where it can 
be seen overhead. Ursa Major is near- 
ly overhead in the latitudes of the 
United States. It is in this position in 
the early evening in the warm months 
of the year. Orion is visible here in the 
early evenings during the winter 
months. Ursa Major is easily described 
by comparison with a dipper. Orion is 
not easily described, but it is hard to 
see how one who has once known it 
1 55 
can easily forget it. Observers too far 
south to see the Ursa Major fill its 
place with a constellation Crux, the 
southern cross, very familiar to them 
but not to us, for we never see it. 
The Planets. 
The position of Venus cannot be 
shown on Figure 1 for the beginning of 
the month, but its position at the end of 
the month is shown. The planet is 
brightest on March 16. Throughout 
the month it will be a splendid object in 
the early evening in the southwestern 
sky. It is so bright that it may be seen 
easily, even at high noon, if one knows 
just where to look. It is hard to locate 
on the bright background of the sky, 
but not hard to see when located. Since 
the planets and their satellites receive 
the light which they give to us from the 
sun, they have phases. It is only pos- 
sible, however, for the planets which 
are closer to the sun than the earth, 
Mercury and Venus, and our moon to 
have the crescent phase. Mercury and 
Venus have no satellites. Venus is now 
of a crescent shape like the new moon. 
Although Venus shows all of the 
phases like the moon, there are some 
very great differences, as might be ex- 
pected, as the motion of Venus is about 
the sun and that of the moon is about 
the earth. Some of these differences are 
these : The brightness of a body de- 
pends both upon its distance from the 
sun and the earth. Neither of these dis- 
tances change greatly in the case of the 
