Star Calendar Planets:
Moon passes just out of reach of Earth’s sizable shadow on the 18th as it sets at dawn. It is very close to being, or not being, a technical penumbral encounter – but nothing observable will occur. Some eclipse tables will list this event, others will not. Both are correct! An annular solar eclipse will cross Africa and Madagascar on September 1st when the Moon’s shadow doesn’t quite reach the Earth.
Mercury makes its widest excursion from the Sun this month but does so doubly disadvantaged from our point of view. Firstly the ecliptic is dropping dramatically to the left of the Sun (aka the coming decent into fall) and secondly Mercury is passing rather south of the ecliptic line. At greatest elongation on the 27th, Jupiter and Venus have a lesser elongation but stand higher than Mercury in the evening – as they are north of the ecliptic just now.
Venus sets at 9:PM on the 1st and then about one minute earlier each day thereafter – but the Sun sets even earlier, gaining about a minute and 21 seconds each day – so Venus is a little higher each evening twilight relative to sunset but is lower each evening relative to the clock. During this month she will pass Regulus, Jupiter and Mercury.
Sun stands in the middle of Cancer as the month begins, crosses into astronomical Leo on the 9th and reaches Regulus on the 21st. If you recall where Jupiter stood (beneath the belly of Leo) at the extremity of his last loop (stationary on May 9), the Sun will reach that spot on September 5th.
Mars will make a striking equilateral triangle with Saturn and Antares, in the south on the 11th, but the Moon standing directly above him will make a distracting lozenge – or possibly blot out Antares. So perhaps on any other day it is a good time to contrast Mars with Antares as they approach one another. They are conjunct on the 23rd/24th.
Jupiter is in direct motion, meaning that he appears further leftwards each day against the stars. The Sun and Moon epitomize this motion and the planets execute variations and contrasts to this theme. Venus is moving more quickly than the Sun, Jupiter more slowly – and Venus will catch up on the 27th for a very close and very bright conjunction. That would be a night to find a 10 to 30 power telescope with either not too large an aperture or fitted with some filters, for Venus will be so close that she’ll mingle amongst the Moons of Jupiter. The pair will be low and due West at 8:15 PM at the very beginning of Nautical Twilight conditions. Find a good spot ahead of time.
Saturn is within the meridia of Scorpius, (though astronomically in Ophiucus) and stands above (north of) Antares. Mars will cut between the two on the 23rd/24th.
Perseid meteors statistically peak mid-month, but the gibbous Moon presents a liability then. There have been known to be earlier outbursts however, so gazing Perseus/Cassiopeia-wards earlier in the month may reward. The Aurigids peak in better conditions at the end of the month – but are above the horizon in the pre-dawn hours – raying from above Orion’s shoulder.
Star Calendar Days:
1 Sunrise/sunset in Spring Valley at 5:52/20:12 (14h20m daylight)
2 New Moon
4 Mercury to right of young Moon, 8:45PM in West
Also, lower to right, Venus
5 Venus and Regulus conjunct in evening, latter probably washed out by sunset
6 Moon just beneath Jupiter, setting by 9:30 PM in West
11 Moon, Mars, Antares, Saturn make a lozenge in SSW at 9:PM
12 Perseids peak – by statistics of the past
13 Saturn stationary to direct motion
16 Mercury at largest (but very low) angle from Sun for this appearance, 27 degrees
18 Full Red Moon (5:27 AM) sets in slight penumbral eclipse in early morning
23-25 Mars passes between Saturn and Antares, SSW in evening
27 Venus and Jupiter pass very close in West as Sun sets – should be quite bright
30 Mercury stationary to retrograde
31 Sunrise/sunset in Spring Valley at 6:22/19:30 (13h8m daylight)