Skywatch Line for Monday and Tuesday, August 5th and 6th, written by Joe Slomka
This is the Skywatch Line for Monday and Tuesday, August 5th and 6th, written by Joe Slomka.
The Sun sets at 8:10 PM; night falls at 10:04. Dawn begins at 3:59 AM and ends with the Sun rising at 5:53.
Leo encloses the Moon on both nights. Monday’s western Moon rises at 6:47 AM by 9 PM lies very close to the horizon and sets at 9:07 PM. The Moon lies 1/2° above Venus – a challenge that requires a clear horizon and binoculars; suggest observers start looking at 30 minutes after sunset, about 8:43 PM. Tuesday’s rises at 7:52 AM, by 9 PM 3° high in the West, 29 arc-minutes, 6% illuminated and sets at 9:26 PM.
Monday’s Moon is close to Venus and Mercury. Venus is the first visible PM planet during Civil Twilight (8:30 PM), blazing with minus 4th magnitude, 10 arc-seconds, 5° high, 47% lit and sets at 8:56 PM; this is the closest conjunction of Venus and Moon for the year. Mercury shines with 1st magnitude, 10 arc-seconds, 20% lit, 2° high and sets at 8:36 PM.
Saturn rises in southern Aquarius at 12:39 AM, zero magnitude, 18 arc-seconds in size, highest at 3:17 AM and 40° at 4 AM. Neptune, 11° behind Saturn, rises in southern Pisces at 10 PM, glows with 7th magnitude, 2 arc-seconds and also 40° highest at 3:57 AM.
Eastern Taurus amasses Uranus, Mars and Jupiter. Uranus rises at 12:21 AM, glows with 5th magnitude, 3 arc-seconds and 39° high. Red Planet Mars, 13° from Uranus, rises at 1:08 AM, 1st magnitude and brightening, 6 arc-seconds, and 30° high. Mars passes 5° from the bright star Aldebaran.
Finally, Jupiter rises at 1:26 AM, flashing with minus 2nd magnitude, 36 arc-seconds, 27° high and its distance from Mars is about 1/2° Wednesday’s pre-Dawn sky is very active. The Great Red Spot (a giant storm) begins at 1:39 AM, followed by many lunar events that begin at 2:47 and end at 3:57 AM. All Dawn planets set during daytime.
Dwarf Planet 1Ceres rises in the South at 6:44 PM, highest at 10:34 and sets at 2:29 AM; it glimmers with 8th magnitude, 0.6 arc=seconds and, by midnight, is 13° high.
The star Algol eclipses at 1:20 AM on Tuesday. Algol, the “Demon Star” varies its light every 2 days, 20 hours and 49 minutes. It fades from second magnitude to third – easily seen by the naked eye. Astronomer John Goodricke theorized that a dimmer star was partially eclipsing the brighter star. In 1889, the new technique of spectroscopy verified this theory. The main star is one hundred times the Sun’s luminosity; the eclipsing star is slightly brighter than our Sun. There is a third star that orbits the system once every 1.8 years, but plays little part in the occultation. The system is about 100 light years away and the most easily studied “eclipsing binary.” Astronomy magazines and websites provide timetables of its eclipses.
Clear Skies Joe Slomka