For July 2024, the Thunder Moon, is July 3. The Earth is at aphelion, farthest from the Sun, on July 6, meaning the sun appears smallest and dimmest in our sky then. Obviously, the fact that we in the northern hemisphere are tilted most toward it in summer makes a far bigger difference in our seasons, for this distance variation is only about 1% — our orbit is almost circular. The waning gibbous moon passes south of Saturn on July 7. The last quarter moon is July 9, and the waning crescent passes Jupiter on July 11. The new moon is July 17. The very slender waxing crescent lies just to the right of Mercury low in the west 45 minutes after sunset on July 18, is just north of the triangle of the Venus, Regulus, and Mars on July 19 (great photo op!), and above the trio on July 20 just right of Mars. The first quarter moon is on July 25.
Planets in Greek means “the wanderers." Never more than this month’s evening sky, as the complex motions of inferior Venus retrograding contrasts with superior Mars in direct motion. For the last two months, faster moving Venus has been overtaking more distant Mars in the western sky night by night, but she never catches him! Instead she has reached the edge of her orbit, half lit in the telescope, and for July, appears as a larger but slimmer crescent each evening, heading back west to pass between us and the Sun in August. She will spend the last four months of 2023 in the dawn sky. As July begins, Mars lies midway between brilliant Venus (so bright it is visible in daylight now) and Regulus in Leo. Mars passes just above Regulus July 9, and Venus comes close, but never reaches Regulus, passing south of it on July 19. To make it more interesting, Mercury comes out from behind the Sun in late July, passing just north of Venus on July 24, and appearing to merge naked eye with Regulus on July 28. Use binoculars to resolve them, with Venus just below them. Quite an end to a busy month!
Things much more placid in the dawn sky, with Saturn rising about 11 p.m. in Aquarius, and Jupiter about 3 a.m. in Aries. Both will return to the evening sky by fall. I observed Saturn last week, and it is notable just how much the rings have flattened since last year. They will be at equinox, facing the Sun and earth edge on, in May 2025, and appear so thin as to vanish for several weeks in most earth based telescopes.
Visit skymaps.com download the map for July for a more extensive list of best objects for the naked eyes, binoculars, and scopes on the back of the map.
High overhead is the Big Dipper, and its handle will be the guide to the biggest news in cosmology in 2023. Just north of the end of the handle is M-101, the “Pinwheel Galaxy," one of the most photogenic spirals and best known galaxies in the whole sky, visible even with big binoculars.
Taking the arc in the Dipper’s handle, we “arc” southeast to bright orange Arcturus, the brightest star of Spring. Cooler than our yellow Sun, and much poorer in heavy elements, some believe its strange motion reveals it to be an invading star from another smaller galaxy. This is the Sagittarius Dwarf Galaxy, now colliding with the Milky Way in Sagittarius in the summer sky. It lies on the far edge of our own barred spiral, and may account for the formation of our bar. Moving almost perpendicular to the plane of our Milky Way, Arcturus was the first star in the sky where its proper motion across the historic sky was noted, by Edmund Halley.
Spike south to Spica, the hot blue star in Virgo, then curve to Corvus the Crow, a four sided grouping. North of Corvus, in the arms of Virgo, is where our large scopes will show members of the Virgo Supercluster, a swarm of over a thousand galaxies about 50 million light years distant.
To the east, Hercules is well up, with the nice globular cluster M-13 marked on your sky map and visible in binocs. The brightest star of the northern hemisphere, Vega (from Carl Sagan’s novel and movie, “Contact”), rises in the NE as twilight deepens. Twice as hot as our Sun, it appears blue-white, like most bright stars.
Northeast of Lyra is Cygnus, the Swan, flying down the Milky Way. Its bright star Deneb, at the top of the “northern cross” is one of the luminaries of the Galaxy, about 50,000 times more luminous than our Sun and around 3,000 light years distant. of the Galaxy, and a little above (north) of Vega.
South of Deneb, on a dark clear night, note the “Great Rift”, a dark nebula in front of our solar system as we revolve around the core of the Milky Way in the Galactic Year of 250 million of our own years. The star at the south end of the Northern Cross is one of my favorites, Albireo, the “gator star”, a notable orange and blue double at 20X.
Altair is the third bright star of the summer triangle. It lies in Aquila the Eagle, and is much closer than Deneb; it lies within about 13 light years of our Sun.
As we head south, Antares is well up at sunset in Scorpius. It appears reddish (its Greek name means rival of Ares or Mars to the Latins) because it is half as hot as our yellow Sun. It is bright because it is a bloated red supergiant, big enough to swallow up our solar system all the way out to Saturn’s orbit! Scorpius is the brightest constellation in the sky, with 13 stars brighter than the pole star Polaris! Note the fine naked eye clusters M-6 and M-7, just to the left of the Scorpion’s tail.
Just a little east of the Scorpion’s tail is the teapot shape of Sagittarius, which lies toward the center of the Milky Way. From a dark sky site, you can pick out the fine stellar nursery, M-8, the Lagoon Nebula, like a cloud of steam coming out of the teapot’s spout. This view of our home galaxy stretching overhead is for about midnight on July evenings, looking from the South to overhead. My favorite way of learning the many deep sky objects is to use low power binoculars (I prefer 8x40s because they are light and easier to hold steady with my Parkinson’s, but younger folks with a better grip on life will find 10x50’s will show fainter objects and at high power) and lean back in a lawn chair (also an ideal way to observe meteor showers like August’s Perseids with just your naked eyes) and slowly sweep up and down the Galaxy, marking off the deep sky objects on your SkyMap as you spot them.
The Escambia Amateur Astronomers return to Casino Beach for our Pavilion Stargaze Season on the first quarter moon. Meet us south of the famed Beach Ball Water Tower and bring your smart phone to image the Sun (before sunset with our solar scopes), Moon, and constellations. We have free star charts and will show you what’s up. The gazes, if clear skies permit, will be on the Fridays and Saturdays for these weekends: July 28-29, August 25-26, and the last on September 22-23.
For deep skies with much less light pollution, on the weekends of the third quarter moon we continue our cooperation with the Florida State Parks at Big Lagoon State Park. While the Pavilion parking is free, normal entry fees to Big Lagoon still apply, and remember to check in the front gate before it closes at sunset. Our gazes for best imaging of the Milky Way, constellations, and other galaxies are on these Saturdays:July 8, August 12 (Perseid meteors!), and September 9.
For more information on the Escambia Amateur Astronomers, join us on Facebook. You can also call our sponsor, Lauren Rogers at Pensacola State at (850) 291-9334 or lrogers@pensacolastate.edu.
