Skywatch Line for Monday and Tuesday, February 29th and March 1st, 2016

This is the Skywatch Line for Monday and Tuesday, February 29th and March 1st.

The Sun sets at 5:44 PM; twilight ends at 7:18. Dawn begins at 4:56 AM and ends with the Sun rising at 6:30.

The darkening sky contains only one planet, Uranus, and one asteroid, Vesta. Uranus appears as a blue-green dot in Pisces. The minor planet, 4 Vesta, lies about 8 degrees east of Uranus; it also lies about five degrees from the star Alpha Piscium, also known as AlRischa. Both Uranus and Vesta require star charts from astronomy media. Uranus sets at 8:54 PM, Vesta at 9:30.

Jupiter rises during twilight, and, by nightfall, is moderately high in the eastern sky. At magnitude minus 2.5, it is the brightest object in Leo, appearing near the Lion’s rear leg. Jupiter will reach opposition on March 8th.  Opposition means that Jupiter is at its brightest, closest, largest and stays up all night. While Jupiter is best seen through a telescope, moderately powerful binoculars can also provide views of its moons. Telescopic viewers can see, at 10:08 PM Monday, Jovian moon, Callisto, cast its shadow on the planet, followed by the moon itself at 12:22 AM, Tuesday. Callisto’s shadow exits at 1:16 AM, followed by Callisto itself at 2:16 AM. Jupiter is best observed at 12:40 AM.

Mars rises shortly after Midnight. It appears as a red dot in Libra. The planet now shines at zero magnitude and slowly grows larger in our telescopes. It is best seen at about 5 AM. Tuesday’s Moon rises shortly after Mars. It turns Last Quarter at 6:11 PM and blazes at minus 10 magnitude near the head of Scorpius. Wednesday, it rises at 1:21 AM, dims slightly and parks itself near Saturn in Ophiuchus. Saturn rises at 1:36 AM and shines at zero magnitude. During March, Mars closes in on Saturn.

Venus rises at 5:32 AM and blazes at minus 4 magnitude. However, it hovers only four degrees above the eastern horizon. In telescopes, it appears about 91 percent illuminated.

Monday is February 29. When most months have 30 or 31 days, why does February have 28 or 29? The old Roman calendar was a lunar calendar of ten months containing 304 days. There was no standard system for inserting “leap months.” The result was chaos. While Julius Caesar was in Egypt, he met Sosigenes, a prominent mathematician, who suggested reforms to the Roman calendar.

Julius Caesar adopted those reforms that resulted in the current system of twelve months containing 365 days and leap years. Months contained 30 or 31 days. What is less well known is that he shifted a day from February to the newly named month of July (after himself). Augustus, his successor, also borrowed a day from February, so that August (his month) would be equally as long as July’s.

Bookmark the permalink.