by Rex Parker, Phd director@princetonastronomy.org

June 11 Meeting (7:30pm) – at the NJ State Museum Planetarium. We’ve come to the last meeting of our “academic” season, to be held at the NJ State Museum Planetarium in Trenton. The museum is located at 205 W State Street next to the NJ State House (gold dome). Park in the lot at the bottom of the hill behind the museum next to the planetarium dome. See Ira’s section in this issue for program information.

Galaxies of Late Spring. It’s not too late to observe some of the Virgo-Coma supercluster of galaxies through telescopes this month. This gigantic grouping of galaxies spans about 15 million light years with approximate center about 60 million light years away. Dozens of the larger and higher brightness magnitude galaxies in this group can be seen in telescopes with 8-16 inch mirrors, such as the Celestron-14 at the AAAP observatory in Washington Crossing State Park. The view angles presented by different galaxies range from edge-on to face-on, which along with distance greatly affect surface brightness and aspect ratio in the telescope. One of the prototypical face-on galaxies in the Virgo group is Messier 100 (M100), a beautifully structured spiral about 50 million light years away from us. The image below is processed from about 45 hours of CCD data (luminance, red, green, and blue) for M100 acquired by remote astrophotography using a 16-inch telescope at Cerro Tololo in the Chilean Andes. The final image shows M100’s distinct morphology and predominantly blue color with patches of glowing red ionized hydrogen H-II regions of new star formation. As discussed at recent meetings, visual observing through the eyepiece won’t reveal these colors due to low light level constraints in human eye physiology. Still, many observers subjectively feel a profound cosmological sensation from seeing spiral galaxies like M100 in a telescope eyepiece.

Messier 100, spiral galaxy in the Virgo-Coma Supercluster. Image by Rex Parker using the 16-inch PROMPT2 telescope from Cerro Tololo, Chile (Star Shadows Remote Observatory).

Skynet Project Renewal. Good news! AAAP has renewed the contract with Skynet for another two years. Two years ago we began a project to bring access to remote astrophotography to AAAP members. Skynet is the brainchild of Dr Dan Reichart of the Physics and Astronomy Dept at the University of North Carolina, Chapel Hill. The internet-based queue scheduling program runs on a computer at UNC which accesses a system of observatories created for remote imaging. This system, the Skynet Robotic Telescope Network, comprises more than a dozen telescopes around the world at observatories in Chile, Australia, Italy, Canada, and US. Each telescope is set up with robotic tracking mount, CCD camera, and filters for remote color image acquisition. Tutorial videos are available to help a user get up and running. For further background read my article in the June 2017 issue of Sidereal Times available from the AAAP website archive.

Whether you’re a first-time astronomer or seasoned observer, Skynet’s easy-to-use yet powerful interface allows you to get images of celestial objects from the Messier and NGC deep sky catalogs. Skynet also includes a basic image processing program “Afterglow” that runs on the server, so you don’t need any special software on your PC. You also can download and process your images locally with your own programs like CCD Stack or Maxim DL if you like. While there are limits on the length of exposures, Skynet is a great way to get onto the learning curve for astro-imaging and understanding how the modern practice of astronomy works. Current AAAP members who have used the system will have new credits added to their accounts. If you are interested in access to Skynet send me an e-mail note to get a new user account.

The Moon in All It’s Glory. Celebrating the achievements of the Apollo program will reach a crescendo this summer for the 50th anniversary of the Apollo 11 landing in July. With kudo’s to our May speaker, James Chen (author of How to Find the Apollo Landing Sites, published by Springer), I took the liberty of assembling a composite of all the lunar landing sites on an image of the nearly full moon I took a couple years ago with a small refractor telescope. One of many remarkable aspects of the landings is how close together they were in both time and space on the moon’s surface. Only a small fraction of the landscape was sampled by the 6 locations. All the landings were done in less than 3-1/2 years, a feat that seems impossible today.