Updated July 22, 2024
NOTE: you can now follow the discussion below with a free planetarium program called Stellarium. To access the web version, go to https://stellarium-web.org/ and allow it to access your location to provide you with an accurate simulation of your nighttime sky. Experiment with it to learn more about the constellations mentioned below, and more.
Venus is slowly making its way into the evening sky, joining Mercury which had been there the last couple of weeks. Venus is the easiest to see, at -3.9 magnitude, low in the west northwest, about 20 minutes after sunset. Mercury is a little higher and 12 degrees to the left of Venus but is much fainter: fading from +0.2 to +0.7 this week. Regulus (magnitude +1.4) joins Mercury on the 25th, passing about 2.2 degrees to the upper right of Mercury. To see these objects, a flat WNW horizon, binoculars, and a clear sky are essential. After this week, both Regulus and Mercury fade into the sunset glow, leaving Venus to get higher and more easily visible as the weeks progress.
We continue on “T Cor Nova Watch” these days, with the recurring nova T Coronae Borealis about to go nova. It last did this in 1946 and the way its brightness changes in its light curve, similar to jus prior to the 1946 eruption, is indicating that its eruption may be imminent. Normally one would need a telescope with a finder chart to see this 10th magnitude object, but when it erupts, it will be as bright as Alphecca, the bright “jewel” star in Corona Borealis, the Northern Crown. It will also be right next to Alphecca, which shines at magnitude 2.2, so it is only moderately bright. It can be found about one third of the way from Arcturus to Vega. So keep an eye out each evening for the appearance of this “extra star”. As of 16:48 UT on 22 July, T Cor Bor was still at magnitude 10.3. It lies almost directly overhead as darkness falls these late July evenings.
The Summer Triangle is relatively high in the eastern sky at nightfall. Just above Altair (the right-most part of the Triangle) is a fainter star, Tarazed. This star glows at magnitude +2.7, considerably fainter than Altair’s +0.7. Altair is so bright because it is only 17 light years away, while Tarazed is 380 light year away. The latter is an orange giant star is 170 times more luminous than Altair.
Scorpius is now due south as it gets dark. July is the best month to see it from the northern hemisphere. After this month, it will start to tilt more and more toward the southwestern horizon. Full Moon was 20 July and now it is a waning gibbous rising later and later with each passing evening. Late in the evening of the 24th, the Moon rises with Saturn (around local midnight). As the Moon leaves the evening sky, the time is now to get a good view of the Milky Way Galaxy. In fact, the best time to see it in the evening sky in the Northern Hemisphere is late Summer or August. It stretches from Scorpius in the south up and diagonally to the left through Sagittarius, Aquila, Cygnus and Cepheus. It rises higher with the progress of the evening, reaching overhead around local midnight.
Following Scorpius is Sagittarius, which is easily identified by its teapot asterism. A fluff of Milky Way haze appears just above the spout, giving the appearance of steam coming out of a teapot. As the evening progresses (then as the season progresses the same time each day) the Teapot appear to tilt more and more toward the right.
The Big Dipper now hangs down by its handle relatively low in the northwest as it gets dark. The handle curves up towards Arcturus which is high in the Southwest. The Big Dipper’s pointer stars are the bottom two stars and they point directly towards Polaris. Above Polaris is equally bright Kochab which, along with fainter Pherkad, mark the outside part of the bowl of the Little Dipper. The rest of the Little Dipper is very faint, best seen from away from city lights.
Facing northeast, Cassiopeia is starting to make an appearance in the evening sky, low in the NNE at nightfall. It is led by Cepheus, the house-shaped pattern of stars higher in the northeast. After Cassiopeia, the head of Perseus appears. All of this is higher in the sky the further north you go.
From Vega extends the small constellation Lyra the Lyre (harp). This starts with a little equilateral triangle with Vega at one corner and two 4th magnitude stars at the other corners. From there toward the right, slanted slightly downward is the parallelogram that marks the main part of the constellation. The bottom two stars are beta and gamma Lyrae, the next two brightest stars in Lyra. Typically these two are nearly the same brightness (magnitude 3.4 and 3.25, respectively), but every 12.9 days it drops to 4.3 and becomes noticeably dimmer than gamma. Beta, also known as Sheliak, is an eclipsing binary star where the two components orbit around a common center of mass and eclipse each other as seen from Earth.
In the predawn sky Mars and Saturn are visible high in the east and south southwest around an hour before dawn’s first light. Not far from Mars is dim Neptune, and Uranus is near Jupiter, which is now easily seen relatively high in the east-northeast before and during dawn. The backdrop of these are the constellations of fall, such as Aquarius, Pegasus, and Andromeda. Fomalhaut is low in the south southwest as twilight brightens the skies.
Go to https://skyandtelescope.org/astronomy-news/observing-news/this-weeks-sky-at-a-glance-July-19-26/ for this week’s “Sky at a Glance”, where you will find the current “Sky at a Glance” (currently for the week ending July 26). There are lots of links to interesting news stories and additional observing projects.
Solar observations are on pause until at least 7 August due to expected inclement weather this week and other circumstances. The latest images obtained from Prairie View Solar Observatory can be viewed at https://www.pvamu.edu/pvso/solar-observations-2024/.
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We observed two solar eclipses less than six months apart. Check out images from these celestial events at this site.
We observed and imaged the total lunar eclipsed that occurred during the predawn hours of 8 November 2022. The images and report can be viewed at https://www.pvamu.edu/pvso/cosmic-corner/total-lunar-eclipse-2022-1-2/. Partial lunar eclipse began at 3:09 am CST, total eclipse started at 4:16 am CST, maximum eclipse (when the Moon should appear darkest) at 4:59 am CST, total eclipse ended at 5:42 am CST, and partial eclipse finished at 6:49 am. The subtle penumbral shading was detectable some 30 to 40 minutes before and after the partial stages. Lots more information can be found at Sky and Telescope’s eclipse page.
Over a year ago, a Total Lunar Eclipse, with totality lasting nearly 85 minutes, was visible across North and South America (except the far northwest part of North America). Partial eclipse began at 9:28 pm CDT (May 15), totality began at 10:29 pm, mid eclipse was 11:12 pm, total eclipse ended at 11:54 pm and partial eclipse ended at 12:56 pm, CDT (May 16). We did observe the event and got pictures, check out this website for these.
Jupiter was hit by a meteor in 2021, see https://skyandtelescope.org/astronomy-news/jupiter-whacked-again-japanese-astronomers-record-possible-impact/, for more information on what is the 11th confirmed observation of a fireball to burn up in its atmosphere. We plan to organize a campaign to watch for fireballs in Venus’ atmosphere early this summer; check back for more details in the near future. There was another event documented on 28 August 2023. You can read all about it at this website.
The Perseverance rover continues to perform wonderful feats of science, from finding evidence of a raging river, to making 10 g of pure oxygen from the Martian air to watching a small drone helicopter take its 51st flight over the Martian wasteland. For more information on it and other activity on Mars, visit mars.jpl.nasa.gov. Also, Curiosity has returned some beautiful sunset pictures of cirrus-like clouds in the Martian sky.
Observations of the partial phase of the May 2021 lunar eclipse (taken with smartphone and a University telescope), along with unfiltered, stacked galaxy and cluster images, can be viewed from the project update website https://www.pvamu.edu/pvso/cosmic-corner/project-summary-2/. We are currently experiencing an extended spell of inclement weather, preventing much observing, but as conditions improve we plan to resume nighttime observations along with regular solar observations. Information on all the eclipses that will occur in 2022 can be found at this link.
The PVO complex has 3 domes, including the existing “Classic” Solar Observatory, and two new domes. For updates on this progress check out https://www.pvamu.edu/pvso/cosmic-corner/project-summary-2/. Also, more information and images can be viewed at https://sites.google.com/view/saganti-astro/home. The two newer domes contain our Meade 16-inch advanced telescope (east dome, an Astrohaven clamshell-type dome) and a new 0.6 meter (24-inch) PlaneWave Corrected Dall-Kirkham telescope (west dome, an Ash dome). The design features these two domes situated east and west of a visitor’s center, which is immediately north of the existing Solar Observatory. Work is planned to resume on the 24-inch in early 2024.