### February 2003 Star of the Month: Capella

On February 1st, the brilliant yellow star Capella shines at its highest point for the night at 8:30 p.m. local time. Thereafter, Capella returns to the same place in the sky four minutes earlier with every passing night. If you live at 46 degrees north latitude (such as at the Lac du Flambeau Indian Reservation in northern Wisconsin), Capella stands at zenith or straight overhead at this magical hour. For every degree that you reside north of 46 degrees N. latitude, Capella appears an equal number of degrees south of zenith; conversely, for every degree you live south of 46 degrees N. latitude, Capella appears that many degrees north of zenith.*

Now for a note on local time. If you live on the meridian that governs your time zone (like at Philadelphia, PA or Denver, CO), then your local time is the same as standard time. If, however, you are situated to the east of your time zone line, your local time is ahead of standard time. On the other hand, if you live west of the time zone meridian, local time lags behind standard time. One degree difference of longitude is equal to four minutes variation in time. For example, Woonsocket, RI is at 71.5 degrees W. longitude, or 3.5 degrees east of 75 degrees W. longitude, the meridian governing the Eastern Standard Time zone. Multiplying 3.5 times 4 minutes = 14 minutes, the amount of time local time is ahead of standard time. In Woonsocket, Capella climbs to its highest point on February 1st at 8:30 p.m. local time but 8:16 p.m. standard time. Now let's go westward to Niagara Falls, NY, which resides at 79 degrees W. longitude, or 4 degrees west of 75 degrees W. longitude. Since Niagara Falls' local time is 16 minutes behind standard time, Capella reaches its highest point on February 1st at 8:30 p.m. local time but 8:46 p.m. standard time.

Capella reigns as the northernmost first magnitude star in all the heavens. So if you live in the northern states, you're not likely to mistake Capella for another heavenly body, since no other bright object shines anywhere close to overhead. However, at the latitude of Atlanta, GA (34 degrees N. latitude), things become more ambiguous. It's quite possible to mistake Saturn for Capella, since both are about the same distance from your zenith, and exhibit similar brightness and color. Just remember Capella is to your north and Saturn is south. Anywhere appreciably south of Atlanta's latitude Saturn comes closer to your zenith than does Capella.

If you have difficultly telling north from south, and Capella from Saturn, remember to look for the Moon on the evening of February 11. Saturn sits just below the gibbous Moon.

Incidentally, when Capella reaches its highest point, the constellation Orion also climbs to its loftiest position, taking center stage in the southern sky.

* The width of a finger at an arm length away spans roughly two degrees of sky.