Skywatch Line for Friday, July 19, through Sunday, July 21, written by Sam Salem
This is Dudley Observatory’s Skywatch Line for Friday, July 19, through Sunday, July 21, written by Sam Salem.
On Friday, Sun rises at 5:34am and sets at 8:28pm; Moon sets at 3:01am and rises at 7:42pm.
On Friday, the nearly full Moon tonight shines in the handle of the Sagittarius Teapot. Cover the Moon with your fingertip to help reveal the stars near it.
On Saturday night, the Moon shines low between the Sagittarius Teapot to its right and the dim boat shape of Capricornus to its left, which will be hard to piece out through the moonlight.
Full Moon occurs at 6:16am on Sunday morning. The full Moon will come just in time for the 55th anniversary of the first human footsteps on the Moon in 1969. Look for the full Buck Moon near the Teapot, in Sagittarius the Archer. You can catch the Moon and the Teapot rising in the east at sunset, highest in the sky at midnight, and setting in the west at dawn.
The low Moon on Sunday evening forms a huge, nearly vertical line with Altair about three fists above it and Vega the same distance above Altair, near the zenith. Look just a finger-width at arm’s length above Altair for its eternal little sidekick Tarazed, Gamma Aquilae, a modest magnitude 2.7 compared to Altair’s magnitude 0.7. Altair looks so bright because it’s one of our near neighbors, just 17 light-years away. Tarazed is an orange giant star about 380 light-years farther in the background, and it’s 170 times more luminous than Altair.
Look for Mercury at dusk, quite low in the west-northwest during bright twilight. It is not an easy catch even at about magnitude +0.2. Don’t confuse it with twinklier star Regulus. They’re about 5½° on Friday.
Venus, at magnitude -3.9. is deeper in evening twilight, 14° to Mercury’s lower right, a little more than a fist at arm’s length. Try for Venus 20 minutes after sunset and use binoculars.
Mars, at magnitude +0.9 at the Aries-Taurus border, rises around 2am and glows in the east before and during early dawn. It’s about 1½ fists upper right of bright Jupiter, and roughly half as far lower right or right of the Pleiades. The Pleiades soon become lost from sight once dawn gets under way.
Jupiter, at magnitude –2.0 in the constellation of Taurus, glares in the east-northeast before and during early dawn lower left of Mars.
Saturn, at magnitude 1.0 near the Aquarius-Pisces border, rises around 11pm and stands high in the south-southeast before dawn. Spot the Great Square of Pegasus two fists upper left of it, and Fomalhaut two fists lower right of it.