This is the Skywatch Line for Monday and Tuesday, November 4th and 5th, written by Joe Slomka.
Now that Standard Time has resumed, the Sun sets at 4:44 PM; night falls at 6:20. Dawn begins at 4:58 AM and ends with the Sun rising at 6:34.
The Moon dominates the sky with its brilliance. It reaches First Quarter phase on Monday, inhabits Capricornus, appearing about 50% illuminated and sets at 11:26 PM. Tuesday, the Moon rises in Aquarius, and by Civil Dusk, appears 64% lit and sets at 12:26 AM, Wednesday.
Venus and Mercury continue to bask in the setting Sun’s glow. Venus, in Scorpius, lies about 8° above the western horizon and blazes with minus 4th magnitude. Mercury, to Venus’ lower right, hovers lower above the horizon, about 4°, and glows with first magnitude. Both require an unobstructed horizon and binoculars and set by 5:41 PM.
Gas giant Jupiter, still in Ophiuchus, shines with minus 1st magnitude and lies about 20° east of Venus at an altitude of about 17°. The giant planet sets at 7 PM. Saturn, in Sagittarius, trails Jupiter by about 1 ½ hours and is found 22° to Jupiter’s upper left. It glows with zero magnitude and appears about ½ Jupiter’s size in our telescopes. It sails moderately high, at 24°, in the western sky. The Ringed Planet is high enough in early evening for viewing of its famous rings. It sets at 8:37 PM.
Ice giant planets Neptune and Uranus also persist in their positions. Neptune, in Aquarius, shines with 8th magnitude is highest and best observed at 8 PM and sets at 1:47 AM. Uranus, in Aries, glimmers with 5th magnitude and appears slightly larger than Neptune. Uranus is best observed at 11 PM and sets at 5:57 AM. Both planets present similar colors, diameters, masses, densities and rotation rates. Their atmospheres consist mostly of hydrogen and helium, with about 3% methane, which gives them a blue-green tint. Again, finder charts from astronomy media help in the search.
Asteroid 4Vesta also graces our sky. It shines with 6th magnitude just west of Taurus’ tail. It averages about twice the Earth-Sun distance from Earth and circles the Sun once every 3.6 years. On November 7th, it crosses into Cetus. However, its size is .41 arc-seconds, which requires a telescope or 10X50 binoculars and finder charts from astronomy magazines and websites. Vesta is approaching Earth and now is the best time to view this Solar System member. Vesta reaches Opposition on November 12th, which means it rises at sunset and sets at sunrise and is closest to Earth.
Mars is now becoming more visible. In Virgo, it rises at 4:43 AM and shines with first magnitude. In our telescopes, it appears about 3 arc-seconds in size. Observers are reminded that the rapidly brightening dawn sky makes observation increasingly difficult.
Like planets and comets, asteroids have defined orbits about the Sun. Comets are ice and rock mixes, while asteroids are mostly rock. There are several types of asteroid. Some orbit between Jupiter and Mars, others accompany planets, and then there are interlopers from the far reaches of the solar system.
Vesta is the fourth dwarf planet to be discovered. It orbits the Sun every 3.6 years, and is nearing opposition. Like the first three asteroids, Vesta was temporarily named a planet, until astronomers realized their small size. Vesta is the brightest, shining at magnitude 6.6. It can be seen in binoculars from a dark, rural site. Vesta currently inhabits the body of Taurus, the Bull. Those seeking Vesta should consult magazine articles and web sites to identify the asteroid amid similar looking stars.