Transient Events That Can Give Us a Good Enough Reason
to Get Outside and Do a Little Observing
All month: Mars continues to have the evening sky to itself this month, but it doesn’t make much use of it,
setting just after 10 pm (less than 2 hours after the Sun) as August begins and shortly before 9 pm (less than
90 minutes after sunset) as the month ends. The Red Planet doesn’t cut much of a figure right now, gleaming
at a feeble mag +1.6 with a disk barely 4 arcseconds wide – far too small to show surface detail in amateur-
sized scopes. Around the time Mars sets, Saturn and Neptune rise, before 10:30 pm on Aug 1 and before
8:30 on Aug 31, putting some solar system representation into the late night time slot. The two planets
remain within a degree or two of each other all month. Saturn’s 19 arcsecond disk shines at mag +0.7 to +0.8
and its rings remain nearly flat, tilted only 3° from our perspective, with their south side exposed. Neptune’s
2 arcsecond disk is a binocular target at mag +7.8. Uranus follows a couple hours later, rising at 12:45 am as
August opens and before 11 pm as it ends, its 3½ arcsecond disk glowing a soft blue at mag 5.7 as it crosses
the sky 5° below The Pleiades (M45) all month. The month’s most spectacular event will be the close pairing
of Venus and Jupiter the morning of Aug 12. Venus starts the month rising at 2:25 am but moves that back to
3:30 am by month’s end, starting the month at mag -4.0 as a 14 arcsecond gibbous disk 75% illuminated, and
ending at mag -3.9 with a 12 arcsecond disk 84% lit. Jupiter breaks the east horizon just before 3:30 am on
Aug 1 and just before 2 am on Aug 31, with a 33 to 34 arcsecond disk gleaming at mag -1.9 to -2.0 during the
month. That leaves only Mercury: it begins August at inferior conjunction and slowly emerges into the
morning sky after mid-month. It’s near dichotomy (48% illuminated) with a 7 arcsecond disk glowing at mag
-0.4 on Aug 21, losing some size while gaining some brightness to end the month with a 5½ arcsecond disk
85% lit at mag -1.2. Among the asteroids, 4 Vesta concludes its long evening run in Libra, but is now low in
the western sky and sets soon after the Sun – but to take its place, 6 Hebe reaches opposition Aug 25 at mag
7.6 among the stars of Aquarius. This month’s charts will show you where to find it.
Aug 2: large scope owners have another chance to catch Saturn’s moon Titan in a shadow transit after
midnight tonight, as the moon’s shadow slowly slips onto the planet’s disk between 1:05 and 1:25 am CDT,
reaching the planet’s midpoint between 3:30 and 4:00 am and sliding back into the background sky between
6:00 and 6:30 am, after sunrise. As noted last month, you’ll need at least 6” of aperture (and preferably
more) and at least 150x magnification to see this show, which can only be seen while Saturn’s rings are
relatively flat from our perspective.
Aug 3: take a look outside between 8:30 and 11:30 pm CDT for a “what’s wrong with this picture” test as the
gibbous Moon crosses the sky a degree below Antares (Alpha [] Scorpii) – an arrangement that can happen
only because, as noted last month, the Moon is in the midst of a major lunar standstill as it passes through
the most southerly part of its 18.6 year orbital cycle.
Aug 5-6: look for more proof of the lunar standstill tonight and tomorrow, as the Moon sits within the teapot
of Sagittarius on the 5th and behind it on the 6th, again reaching points far south of its usual path.
Aug 8-16: check the eastern sky between 3:30 am CDT and morning twilight any of these days to enjoy a
view of Venus and Jupiter within a 5° binocular field of each other.
Aug 12 (morning): Venus and Jupiter reach their closest separation this morning, with less than a degree
between them. Catch the display any time from 3:30 am CDT until morning twilight gets in the way around 5
am. After admiring that view, look to the south, where mag +0.8 Saturn is 3½° behind the 89% illuminated
gibbous Moon. If you’re using binoculars or a telescope, check 1° directly above Saturn to spot tiny blue
Neptune, a faint mag 7.8, at the point of a right angle between the two larger solar system targets.
Aug 12 (evening): the Perseids meteor shower reaches its peak tonight, hampered by a bright gibbous
Moon, just 3 days after full, that rises before 10 pm and sticks around through sunrise. With a zenithal hourly
rate (ZHR) often estimated at 150 meteors per hour under dark skies, the Perseids can be a prolific shower,
but the Moon will wash out all but the brightest of them this year, so you’ll likely see fewer than a dozen each
hour. Since the Perseids are active from July 17 until Aug 24, you’ll probably see a few of them this month
even when you’re not looking for them – but for the experience of seeing them at their best, you’ll have to
wait until next year, when they peak on a night when the moon will not be a factor.
Aug 16: if you’re up early this morning (or late last night), watch The Pleiades (M45) chase the third quarter
Moon across the sky. The Seven Sisters start out 5½° behind the Moon around 12:30 am CDT and gain
ground all night, but are still 2½° behind when morning twilight erases the scene around 5 am.
Aug 19: it’s another Titan shadow transit tonight (see Aug 3 above). This one starts between 12:30 and 1:00
am CDT, reaches Saturn’s meridian around 3 am, and ends in morning twilight between 5:00 and 5:30 am.
Aug 20: early risers are greeted by a complicated scene low in the eastern sky between 3:30 am CDT and
sunrise today, starting with a triangle formed by the crescent Moon, just 9% illuminated and perched 4°
above left of bright mag -3.9 Venus, with mag -2.0 Jupiter to their upper right. Meanwhile, Pollux and Castor
(mag 1.2 and 1.9 respectively) form an 11° arc extending above left from the Moon. It gets even more
interesting just before 5 am, when mag -0.3 Mercury rises, with the faint stars of The Beehive Cluster (M44)
visible in binoculars or a telescope 2° to its upper left. The scene becomes more orderly tomorrow morning
as the Moon – now an even narrower crescent just 3½° illuminated – drops down to form a straight line with
Venus and Jupiter, with Mercury 4½° behind the Moon and The Beehive directly between them.
Aug 25: new Moon arrived Aug 23 at 1:07 am CDT, and yesterday it set only 37 minutes after the Sun – but at
8:21 pm CDT tonight (45 minutes after sunset), it will be 2½ days old, 8% illuminated, 2½° above the horizon,
23° left of the spot where the Sun went down, 7° below right of mag +1.6 Mars – and you’ll have just 13
minutes to spot it before it, too, slips below earth’s edge.
Aug 30-31: the first quarter Moon dances with Antares (Alpha [] Scorpii), waltzing along 4½° to the star’s
lower right on the 30th and 7½° to its left on the 31st. The twilight sky makes it easier to see the color
contrast between the bright gray Moon and the ruddy red star.
Rick Gering / August 2025