Skywatch Line for Monday and Tuesday, January 29th and 30th, 2018

This is the Skywatch Line for Monday and Tuesday, January 29th and 30th.

The Sun sets at 5:04 PM; night falls at 6:42. Dawn begins at 5:34 AM and ends with the Sun rising at 7:12.

The nearly full Moon dominates the sky on both nights. Blazing at minus 12th magnitude, the Moon occupies Gemini on Monday evening, appears about 96 percent illuminated, is best observed at 10:45 PM and sets at 6:19 AM, Tuesday. Tuesday night finds an almost full and slightly brighter Moon in Cancer, and is best observed at 11:43 PM. The Moon turns officially “Full” at 8:27 AM on Wednesday.

Eighth magnitude Neptune still glows in Aquarius, near the bright star Hydor, and sets at 7:57 PM. Uranus, still in Pisces, near the star Mu Piscium, shines at 5.8 magnitude and sets at 11:28 PM. Neptune sets earlier daily; now is the time for last looks. Uranus is better situated for observation, but also closer to the brilliant Moon.

Dwarf planet 1Ceres maintains position just above Leo’s nose, shines at 6.8 magnitude and is a tiny 0.7 arc-seconds in our binoculars and telescopes. While 1Ceres becomes officially “in Opposition” at 1 AM on Wednesday, normally the ideal time for observation, finding it may be difficult due to the Moon’s proximity, especially on Tuesday evening.

Neptune, Uranus and 1Ceres requires detailed charts from astronomy media.

Jupiter rises in Libra at 1:35 AM near the star Zubenelgenubi. It shines at minus 2nd magnitude and is about 36 arc-seconds in size. It is best observed at 6:32 AM. With Jupiter rising earlier daily, observers can once more start studying features on its surface. For example, at 5:38 AM on Wednesday, telescopic sky watchers can see the Great Red Spot (a giant storm) centered on Jupiter’s face; they can also witness the Jovian moon Ganymede disappear behind the giant planet at 3:52 AM and reappear at 5:24 AM.

Mars also inhabits Libra, but appears close to Scorpius’ head; it rises at 2:34 AM, about 11 degrees below Jupiter. The Red Planet shines at 1st magnitude, appears about 6 arc-seconds in size and 92 percent lit.

Saturn rises in Sagittarius at 5:03 AM, about 32 degrees below Mars. Saturn shines with 0.6 magnitude. However, its low altitude makes observation difficult; binoculars are suggested.

By 10 PM, the constellations Orion and his dog Canis Major lie in the South. The brightest star in Canis Major, Sirius or the Dog Star, is also the brightest in our sky. The word “Sirius” means “scorching.”

Alvan Graham Clark was the son of Alvan Clark. The Clarks and their company were famous 19th Century telescope makers. Antique telescope collectors and amateur astronomers prize Clark telescopes for their beauty and technical excellence.

Alvan Graham, over 150 years ago, was testing a newly finished 18 and one-half inch refracting telescope. He trained it on Sirius. He saw a faint companion to the main star – the first known white dwarf star. Sirius B, as this companion is called and nicknamed “The Pup”, orbits the main star in about 50 years. It is far hotter than Sirius, slightly smaller than Earth, but nearly the Sun’s mass. Sirius B is actually a remnant of a far larger star that died, and is slowly cooling off.

The telescope that Alvan tested was installed at Northwestern University and is still in use.

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