This is Dudley Observatory’s Skywatch Line for Friday, March 24, through Sunday, March 26, written by Sam Salem.
On Friday, Sun rises at 6:52am and sets at 7:13pm; the 14% illuminated Waning Crescent Moon rises at 4:57am reaching transit altitude of 33 degrees south at 10:11am and sets at 3:31pm.
Locate Mercury low in the west shining at magnitude –1.1 shortly after sunset. Mars at magnitude 1.4 is easy to find in the western sky, roughly 15 degrees high at dusk. Mercury sets at 8:38pm and Mars sets at 10:20pm on Friday. Jupiter rises into southeast at 8:22pm. Observe the –2.4-magnitude Jupiter with a telescope later at night when it climbs above the atmosphere’s blurring effects. Saturn rises in the southeast horizon at 2:03am. Saturn is at its best around 6:00am when the 0.5-magnitude planet reaches its highest point in the sky just before morning twilight begins.
On Saturday morning at 6:18am, Venus is in conjunction at 8 degrees north of Sun and transitions from being the evening “star” to being the morning “star.” The planet will be visible low in the east shortly before sunrise a few days later. It is possible to see Venus in both morning and evening within a few days of Saturday. Venus rises briefly before sunrise at 6:09am and sets shortly after sunset at 7:23pm on Saturday, rising and setting a few minutes earlier in the next days.
On Sunday night, look for the planets Mercury and Uranus low in the western sky 45 to 60 minutes after sunset. Mercury and Uranus will be closest together on the sky’s dome on Sunday and Monday. On both evenings, you might be able to see both planets within the same binocular field of view. Mercury sets at 8:48pm and Uranus sets at 8:40pm on Sunday night.
The Big Dipper is part of the constellation Ursa Major, the Greater Bear. If you can find the Big Dipper, you can also find two Hunting Dogs, seen by the ancients nipping at the Bear’s heels. The Hunting Dogs are a separate constellation, Canes Venatici. In a moonless night locate these two little stars snuggled in the arc of the Big Dipper. The most famous object in this region of the sky is M51, the Whirlpool Galaxy. M3 is another faint object at the extreme edge of Canes Venatici. M3 is a globular star cluster almost midway between the bright star Arcturus and Cor Caroli in Canes Venatici.
Saturday marks the birthdate of the American Astronomer Kenneth Linn Franklin. Dr. Bernard F. Burke and Franklin co-discovered that planet Jupiter emits radio waves when they were scanning the sky for radio waves from galaxies. By chance, they found a radio signal that resembled short bursts of static noise. The signals were periodic, four minutes earlier each day. After weeks of study they pinpointed Jupiter as the source. The discovery was announced in April 1955.
The “Earth Hour” is on Saturday from 8:30pm to 9:30pm. The event is held worldwide annually encouraging individuals, communities, businesses, and households to turn off their non-essential lights for one hour towards the end of March, as a symbol for their commitment to the planet. The event started as a lights-off event in Sydney, Australia, in 2007. Since then, it has grown to engage more than 7000 cities and towns worldwide. www.earthhour.org