07/31/2023
What’s Up in August 2023 from the LAS
The highlight of the month is the annual Perseid meteor shower. This year it will peak around August 13, but is active from mid-July to late August. On August 13th the Moon will be approximately 10% illuminated and will rise around 4am so the night of the 12th is the preferred night. The Perseids are caused by Earth passing through debris — bits of ice and rock — left behind by Comet Swift-Tuttle which last passed close to Earth in 1992. The Perseids peak when Earth passes through the densest and dustiest area of debris. In outburst years (such as in 2016) the rate can be between 150-200 meteors an hour.
August will be a good month for observing the outer planets. At the beginning of the month Saturn rises around 10pm, Neptune around 11pm, Jupiter around 1am and Uranus around 1:30am. By the end of the month each rises about 2 hours earlier making this an excellent time to begin studying Saturn and Jupiter. Saturn is not as dramatic a sight as in previous years since the rings are closing, a consequence of the planet's 27° tilt and how our view of Saturn changes as it orbits the Sun.
Speaking of the Sun, activity is picking up quickly as we head towards the Solar maximum. You can enjoy the Sun with aperture as small as 30mm just make sure to use proper filtering. My favorite website is Spaceweather.com for all things Solar. It also covers interesting phenomena like noctilucent clouds, rainbows, auroras, and STEVE.
As we move towards the fall season, the nights start getting shorter which means that the Milky Way will be high in the sky after midnight. Galaxies become fewer in the skies replaced by globular clusters and star clouds. This is also a time when binoculars are all that is needed for a night’s viewing. Grab a blanket, get out the binoculars and check out the Milky Way (and watch for meteors and satellites).
Some of my favorites this time of the year are the globular clusters. There are around 150 globular clusters in our galaxy, mostly on the outskirts. Many of these are over 13 billion years old, making them some of the oldest objects in the known universe. The constellation Ophiuchus has several globular clusters in it including M10, M12, M14, M19, Palomar 15, NGC 6171, NGC 6218 and many more. For those with larger backyard telescopes we can observe globular cluster in M31 and Small Magellanic Cloud. The Astronomical League (in which all LAS members have membership) has an excellent but challenging Globular Cluster Observing Program.
This is also the time of the year when there is a wide variety of targets available to explore. Nebulas are bountiful ranging from the North American and Veil nebulas in Cygnus to the Trifid and Lagoon nebulas in Sagittarius. And let’s not forget the Ring nebula in Lyra, the great donut in space (that is my description when kids are seeing it for the first time!)
To close out August one of the crown jewels of the night sky is rising, the Double Cluster. This sparkling pair of open clusters is always a showstopper in a wide field scope and eyepiece. Aperture is not needed just a wide field of view and a clear sky.
Until next time, clear skies!
Louisville Astronomical Society
