Skywatch Line for Monday and Tuesday, September 9th and 10th, written by Joe Slomka
This is the Skywatch Line for Monday and Tuesday, September 9th and 10th, written by Joe Slomka.
The Sun sets at 7:15 PM; night falls at 8:52. Dawn begins at 4:53 AM and ends with the Sun rising at 6:30.
Southern Scorpius hosts the Moon on both nights. Monday’s 6-day-old Moon rises at 1:04 PM, by 7:45 PM is 15° high, 30 arc-minutes in size, 38% illuminated and sets at 9:58 PM. Tuesday finds the Moon rising at 2:10 PM, 30 arc-minutes, 48% illuminated and sets at 10:38 PM. Wednesday’ Moon reaches First Quarter at 2:06 AM.
Four planets grace the evening sky. Venus remains close to Virgo’s western horizon, minus 4th magnitude, 11 arc-seconds, 89% lit, 2° high at 8 PM and sets at 8:11 PM. Saturn and Neptune appear close to the eastern skyline and visible all night. Saturn, in Aquarius, rises at 7:16 PM, zero magnitude, 19 arc-seconds, 8° high at 8 PM, highest at 12:51 AM, and sets at 6:21 AM. Neptune is 13° behind Saturn, 8th magnitude, in Pisces, rises at 9:41 PM, highest at 1:37 AM, 4° at 6 AM and sets at 7:29 AM. Dwarf Planet 1Ceres lies in southern Sagittarius, 8th magnitude, ½ arc-second, rises at 4:24 PM, 16° highest at 8:14 PM, 97% lit and sets at 12:08 AM.
Southern Taurus presents Uranus and Jupiter. Uranus rises at 10 PM, glows with 6th magnitude, 3 arc-seconds and 65° at 6 AM. Jupiter, 23° from Uranus rises at 11:23 PM, minus 2nd magnitude, a large 39 arc-seconds and 67° 6 AM. Red Planet Mars, now in Gemini, lies 13° behind Uranus, glows with zero magnitude, 6 arc-seconds, rises at 12:16 AM, 60° at 6 AM and 88% illuminated.
Eastern Mercury rises at 5:02 AM in Leo, shines with zero magnitude, 6 arc-seconds, at 6 AM it is 10°, 68% lit and sets at 6:36 PM. This is prime time to view the elusive planet. Monday achieves Perihelion (closest to the Sun); Tuesday, 40 minutes before sunrise, spots it 2° from Regulus. This is the best time of the year for Northern Hemisphere observers.
Space probes are very expensive objects. They cost millions of dollars to design, launch, and operate. Many probes carry some kind of “fuel” to carry out their mission. The Wide-field Infrared Survey Explorer (WISE) was launched in 2009. Its “fuel” was coolant, so that sensitive imagers could detect dim objects that optical telescopes could not see. After two years, as expected, WISE ran out of fuel and two of its three cameras could no longer work. NASA ended the mission by shutting down WISE.
NASA scientists recycled WISE. WISE saves money by reusing something that is already up and useable. Its third camera is ideal for finding asteroids and comets that are too dim for optical telescopes and pose a threat to Earth; it doesn’t need to be super cooled. Asteroids emit an infrared glow – the result of heating by the Sun. The size of that glow permits estimates of an asteroid’s size. The wide-field camera can sample huge swaths of space, instead of tiny fields that most visible light telescopes produce.
Clear Skies Joe Slomka