This month is somewhat quiet in terms of notable sky events. But we're now in summer so it is a fantastic time for stargazing! Here are some suggestions for what to check out in the dazzling night sky this month.
Catch Some Iconic Nebulas
Scan the Summer Milky Way with astronomy binoculars or a telescope to reveal some of the best emission nebulas of July. In Sagittarius, track down M8 (the "Lagoon Nebula"), M20 (the "Trifid Nebula"), and M17 (the "Swan Nebula"). In the constellation Serpens Cauda, see the delicate "Eagle Nebula" (M16). Try using big binos to frame both M16 and M17 in the same field-of-view, or use a big-aperture telescope to coax out the faint violet glow of M16. Our Star Target Planisphere and our DeepMap 600 come in handy for locating these and other gaze-worthy objects.
New Moon
July 5 is the night of New Moon, which means wonderfully dark skies all night for deep-sky observing. A few nights on either side of New Moon are also excellent, as the Moon is in its crescent phase and doesn't brighten the sky much, and is not up very long anyway, leaving plenty of time to explore the heavens in darkness.
Saturn's Rings are Getting "Edgy"
The good news about Saturn is that it will be visible in the constellation of Aquarius almost all night (depending on your latitude) throughout the month of July. That means you'll have plenty of opportunity to view this usually crowd-pleasing, ringed orb in a telescope or binoculars. But the bad news is that the angle of Saturn's rings as viewed from Earth is closing, and they are already pretty close to edge-on. So don't expect to see that classic profile of Saturn with its iconic ring system on full display. Still, it's kind of cool that every 13 to 15 years we see Saturn with its rings edge-on, when they reflect very little light, making them virtually invisible. That will be the case in spring of 2025.
Mars and Uranus come within spitting distance of each other just before dawn on July 15. The pair will be separated by about just half a degree — the diameter of the full Moon. It's a perfect opportunity to observe orange-hued Mars and greenish Uranus simultaneously in the field of view of a telescope. Look low in the eastern sky.
An Impactful Anniversary
July 16-22 of this year marks the 30th anniversary of the spectacular crash of Comet Shoemaker-Levy 9 into Jupiter. As you may recall, in July of 1994 21 separate pieces of the broken-up comet smashed into Jupiter's atmosphere, one after the other over several days, leaving behind a string of dark scars that could be seen in amateur telescopes for a time (they are no longer present). It was the first collision of two solar system bodies ever to be observed in real time. You can catch Jupiter, sans scars, this month in the early morning sky; look east.
Artist's impression of the Comet Shoemaker-Levy 9 in its 2004 collision approach with Jupiter. Artist's description: "The view from a fragment of the Shoemaker / Levy 9 comet which fell into Jupiter piece by piece over several days in Late July 1994, around the 25th anniversary of Apollo 11. Acrylic on board for NASA Ames." Image courtesy of Don Davis. Public domain.
Mercury at Greatest Eastern Elongation
The inner planet Mercury never moves far from the Sun, from our perspective. But on July 22 the planet appears at its farthest distance from our nearest star in the evening sky — the so-called greatest eastern elongation. Which is to say that it appears highest above the horizon in the evening on that date. So it's the perfect time to take a look at Mercury with your telescope or binoculars. Look for it low in the western sky just after sunset. If you use a telescope you can see Mercury's phases. How much of its disc is illuminated today?
Delta Aquarids Meteor Shower
July winds down with the Delta Aquarids meteor shower. For the best chance to see meteors, look towards Aquarius after midnight on July 28 into the early morning hours of the 29th. The Delta Aquarids shower typically produces up to 20 meteors per hour. This year, the waning crescent Moon may wash out some of the fainter ones.
Triangle of Crescent Moon, Jupiter, and Mars
Don't miss this naked-eye treat on July 30! But you'll have to get up early. The crescent Moon, Jupiter, and Mars form a pretty triangle in the eastern sky, not far below M45, the Pleiades star cluster.
July Challenge Object - Hercules Galaxy Cluster
About half a billion light years from Earth in the constellation Hercules, not far from the star Beta Hercules in the southwest corner of the "keystone" asterism, lies Abell 2151, the "Hercules Galaxy Cluster." This association is a group of 200-300 distant galaxies, the brightest of which is NGC 6050 at about 10th magnitude and can be seen with an 8" reflector under very dark skies with good seeing conditions. A larger aperture, 14"-16" telescope will begin to show about a half-dozen or more galaxies in one field-of-view. How many can you see in your telescope? Photographs taken with 8" and larger telescopes have a "Hubble Deep Field" vibe, revealing a myriad of tiny galaxies scattered across the frame.
Hercules Galaxy Cluster from the Mount Lemmon SkyCenter Schulman Telescope. Image courtesy of Adam Block. Used by permission.
All objects described above can easily be seen with the suggested equipment from a dark sky site and on a night when bright moonlight does not overpower the stars.
