This month, the new moon occurs on Sept. 2. It lies just south of Venus in the dusk on Sept. 5, and is first quarter on Sept. 11. The waxing gibbous moon lies just west of Saturn in twilight on September. This full moon, the Harvest Moon, on Sept. 17, finds the moon moving through the earth’s outer penumbral shadow, with maximum slight fading at 9:44 p.m. CDT. The autumnal equinox begins this year on Sept. 22 at 7:44 a.m. The last quarter moon is on Sept. 24, when it passes north of bright Jupiter in the dawn. It passes north of Mars on the following morning.
Mercury lies close to the old moon on Sept. 1 in the dawn, and reaches greatest western elongation, only 18 degrees from Sun, on Sept. 5, and is lost in the sun’s glare by mid-month.
Venus returned to the evening sky in August and will dominate the western twilight through the end of 2024. It is a bright, round disk now, almost fully lit on the far side of the sun. Here is a shot of it and the crescent moon on Aug. 5 with my SeeStar. (see right)
Saturn is at its best this month, reaching opposition on Sept. 7. But it is nearing its equinox in 2025, so its famed rings are almost closed. Our shot comes from Escambia Amateur Astronomer Marc Glover with his 8” telescope on Aug. 7.
For a detailed map of northern hemisphere skies, visit Skymaps.com and download the map for September 2024.
To the northwest, we find the familiar Big Dipper getting lower each evening. Most know how to use the two-pointers at the lower part of the bowl to find Polaris, our Pole Star, sitting about 30 degrees high all night in the northern sky for the Gulf Coast.
From the Dipper’s handle, we “arc” southeast to bright orange Arcturus, the brightest star of spring, and still well up in the western twilight. Just above Bootes, still almost overhead at twilight, is the tiny Corona Borealis. We continue to wait for its “Blaze Star”, T C Br, to erupt as a dwarf nova, which most astrophysicists predict would happen by this month. It last occurred in 1946, and became as bright as Polaris for several days, but has frustrated us so far. It will erupt just east of the easternmost star in the crown, epsilon Coronal Borealis, and should be making news everywhere when it blows at last.
To the south, Antares marks the heart of Scorpius. It appears reddish (its Greek name means rival of Ares or Mars to the Romans) 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! Near the tail of the Scorpion are two fine open clusters, faintly visible to the naked eye, and spectacular in binoculars. The clusters lie to the upper left of the bright double star that marks the stinger in the Scorpion’s tail. The brighter, M-7, is also known as Ptolemy’s Cluster, since he included it in his star catalog about 200 AD. M-6 will appear below it in the same wide binocular field.
The brightest star of the northern hemisphere, Vega dominates the northeast sky. Binoculars reveal the small star just to the northeast of Vega, epsilon Lyrae, as a nice double. Larger telescopes at 150X reveal each of this pair is another close double, hence its nickname, “The Double Double.” This is a fine sight under steady-seeing conditions over 150X with scopes 4” or larger. Between the two bottom stars; the Ring Nebula, marked “M-57” on the Skymap, is a ring of gas and dust expelled by a dying red giant star while its core collapsed to a white dwarf. A similar fate is expected for our own sun in perhaps five billion more years. The tiny white dwarf, like the one in the T Corona Borealis nova system, has shrunk down to the size of Earth, by crushing its electron shells, so while the atomic nuclei are still intact, they are not normal atoms with chemical reactions.
To the northeast of Vega is Deneb, the brightest star of Cygnus the Swan. It was just northwest of it that I discovered the brightest nova of my lifetime, Nova Cygni, on August 27, 1975. Here a shell of hydrogen around a white dwarf exploded, becoming a record (for a nova, at least) 20 million times brighter in a matter of hours. It went from not visible in any telescope to the sixth brightest star in the summer sky in less than a day, and I was looking at the right place and time to catch it still on the rise. But the total amount of expelled gases was much less than in the Ring Nebula, and it faded below naked-eye visibility in only two weeks. Fun while it lasted! Typically several nova outbursts are found every year in our Galaxy, and they do often recur, for neither star in the close binary system was destroyed, and the mass transfer can resume soon.
At the other end of the “northern Cross” that makes up the body of Cygnus is Albireo, the finest and most colorful double star in the sky. Its orange and blue members (I call them the “Gator Stars”) are well resolved at 20X by any small scope.
To the south of Cygnus is Altair, the brightest star of Aquila the Eagle, the third member of the three bright stars that make the Summer Triangle so obvious in the northeast these clear September evenings. South of Aquila is M-16, the Eagle Nebula. In its center is the famed “Pillars of Creation " (see above).
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 smartphone 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 Fridays and Saturdays for these weekends: September 13-14, and October 11-12.
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! Please join us at the amphitheater on Saturday evenings, September 28, and October 26.
Pensacola State’s Science and Space Theatre premieres “Death of the Dinosaurs” on Sept. 6 at 6 p.m. The last four shows have SOLD OUT. Tickets are $6 for adults and $5 for students. They are back thanks to the support of the Merry Edenton-Wooten Endowed Chair in Space Sciences; Merry’s planetarium artwork for NASA is on display in the Foyer, named in her honor. Please order them in advance; they are available at:
For more information on the Escambia Amateur Astronomers, join us on Facebook or online at sites.google.com/view/escambiaastronomers.
