September skies feature Mars, Saturn
Mars and Saturn will be found in the early evening about 10 degrees above the southwestern horizon. By the end of the month, Saturn will be only visible in the glow of twilight and will soon be lost from view. Mars on the other hand, because of its eastward motion in the sky, will continue to set about two hours after sunset, long after Saturn has disappeared from view. Mercury is lost in the glare of the sun for the entire month.
The best planet viewing this month will be in the early morning where both Venus and Jupiter will be very prominent. Jupiter actually rises a little before midnight at the beginning of September and by 10 p.m. at the end of the month. Reaching quadrature (90 degrees west of the sun) on Sept. 7, the giant planet will brighten from magnitude -2.3 to -2.5 by the end of the month.
Venus rises about 3.5 hours before the sun all month. Blazing away at magnitude -4.2, about half of Venus’ disk is illuminated. The best views will be through a good pair of binoculars. As it moves across the starry background, Venus will met and pass many well know stars and clusters, such as Castor and Pollux (on the 6th), M44 the Beehive cluster (on the 12th and 13th) and seems to be homing in on the bright star Regulus in Leo, the lion. Reserve the morning of Oct. 3 for a close encounter of the Regulus kind! (More about this next month.)
The moon will be last quarter on the 8th, new on the 15th, first quarter on the 22nd, and full on the 29th. Since this will be the first full Moon after the autumnal equinox in the northern hemisphere, it will be the “Harvest Moon.” At about one hour after sunrise on the 8th the first quarter Moon will be just above Jupiter, high in the southeastern sky. Folks in the southern hemisphere will see the moon occult pass in front of Jupiter.
Looking east about one hour before sunrise on the 12th, the waning crescent Moon will be slightly above and to the right of Venus. On the 19th, about 45 minutes after sunset, the waxing crescent moon can be found very near the “red planet” Mars. Once again lucky folks in the southern hemisphere will get to see the moon occult Mars.
Autumn begins in the northern hemisphere at 8:49 a.m. MDT on the 22nd. Residents of the southern hemisphere get to enjoy the first day of spring!
Jon Spargo is with the New Mexico Tech Astronomy Club