Skywatch Line for Monday and Tuesday July 3rd, and 4th, 2023
This is the Dudley Observatory’s Skywatch Line for Monday and Tuesday July 3rd, and 4th, written by Joe Slomka.
The Sun sets at 8:38 PM; night falls at 10:52. Dawn begins at 3:08 AM and ends with the Sun rising at 5:23. Note that daylight is very slowly becoming shorter.
Monday’s Moon became “Full” at 7:39 AM, rises at 9:31 PM in Sagittarius, 33 arc-minutes and sets at 6:12 AM on Tuesday. Tuesday’s Moon, rises in Capricornus, at 10:18 PM, highest at 1:49 AM on Wednesday, 96% illuminated and sets at 7:34 AM.
Western Leo contains Venus and Mars. Brilliant Venus is easier to see, since it blazes with minus 4th magnitude and is 35 arc-seconds in size; it lies close to the horizon, only 15° high and sets at 10:40 PM. Venus appears lower daily, its disk grows from 34° to 54°, but its crescent wanes from 31% to 5% this month. Red Planet Mars is close to Venus, gradually pulling away. Mars is about 3° to the upper left of Venus on Monday and to the lower right on Tuesday nights.
Dwarf Planet 1Ceres is still in Virgo, glows with 8th magnitude, 0.5 arc-seconds, 96% lit, 40° high at 9:15 PM and 12° from Denebola. Comet C/2023 E1 still circles the Little Dipper, 14th magnitude, 60% lit, highest at 9:23 PM and 52° high.
The rest of the planets emerge during Dawn, except Mercury (close to the Sun). Saturn rises in southern Aquarius, shining with zero magnitude, a moderate 18 arc-seconds, rises at 11:24 PM and 36° highest at 4:47 AM. Saturn has begun a retrograde (backwards) motion and a prime subject for observation. Neptune, 20° to Saturn’s left in Pisces, undergoes its own retrograde, glowing with 8th magnitude, 2 arc-seconds, rises at 12:12 AM and 40° high in the southeast.
Aries hosts Jupiter and Uranus. Giant Jupiter, sparkles with minus 2nd magnitude, a large 37 arc-seconds, rises at 1:49 AM and 29° high in the East. Tuesday’s Dawn sees the Jovian moon Io’s shadow begins to cross the planet at 2:41 AM, Io starts its trip at 3:55 and the shadow disappears at 4:51. Uranus glimmers with 5th magnitude, 4 arc-seconds, rises at 2:19 AM and 24° high at 4:15 AM.
Low, in eastern Dawn, Cetus, the Whale, is one of bunch of water constellations that begins with Aquarius and ends with Eridanus. Cetus is the home of Mira, one of the first variable stars discovered. While most stars were thought to be constant, Mira periodically dimmed and brightened. Ancients described it “wonderful” (Mira). Mira is a long period variable star that brightens and dims every 332 days. It will be at its peak at about July 13th, shining with a magnitude of 3.4. Tuesday, it lies low in the east about 17° high.