September 2023

Welcome to Hank’s September 2023 Astrophotography Blog. It’s an exciting time to be an amateur astronomer who is taking photos of objects in the sky, as the technology and opportunities are evolving rapidly. For example, NASA makes some of the image data taken by the Hubble and James Webb telescopes available to anyone to process on their own! That’s almost like having your own 10 billion dollar telescope! Well, almost. You can also rent time on large telescopes and use them to capture images you want to capture….or simply download the images they have taken previously. This has intrigued me, as I have never seen the skies of the southern hemisphere, and I’d like to be more familiar with those skies, constellations, and mysteries.

This month I was able to get out a few nights, when the skies were clear.

Of particular interest is a star I read about, Pegasi 51 (Helvetios Pegasus) and photographed. In 1995 this Sun-like star was the first star discovered to have an exoplanet—or a plant that is circling its own sun. The exoplanet is designated 51 Pegasi b (officially named Dimidium). The discovery was made by two Swiss astronomers, Michel Mayor and Didier Queloz, who won the Nobel Prize in Physics for their discovery. The difficulty in spotting exoplanets is that they are so far away. This one being 50.6 light years from us. But the exoplanet can be detected by measuring how much the light of the star dims when the exoplanet passes in front of the star. There are over 5000 known exoplanets, and many more are suspected. The world’s professional observatories can’t keep up with the activity of all these exoplanets, so talented amateur astronomers are asked to participate in contributing to the science. The big news this month was that our Black Hills Astronomical Society now has one member who has successfully measured the transit of an exoplanet across its star-sun! We also have a member who has successfully tracked asteroids to help us predict their orbits, and one member has discovered 25 asteroids!

This month I participated in another star party at our own BHAS Hidden Valley Observatory. It’s always fun to set up my telescope and do a show-and-tell about the night sky. Here are images that I took that night:

One of the great things about belonging to an astronomical club is the sharing that takes place between members. The technology and software are very complicated, but with the support of members I have been able to explore new techniques. This month I learned about SIRIL, a piece of free postprocessing software that allows my one-shot color camera to take advantage of using calibration frames (images that compensate for problems with my camera and telescope), long exposures, and allows me to “clean up” my photos and bring out faint details, while diminishing an overly bright star field. I was able to capture 3 different targets and processed them multiple times to get a better understanding of how the software works. I used my HyperStar lens that gives a broad field of view, and a filter that blocks some of the brightness of the Moon, as the Moon was nearly full.
All were 32 second frames for a total of 20 minutes of exposure time.
Here are the results.

On October 14th there will be an annular eclipse, that will be visible over all of the northern hemisphere. Annular eclipse’s are different than a total eclipse in that they show a narrow ring around the rim of the Sun, so it does not go to totality. But it is still very cool! Here in Custer we are far enough off from the center that we will only get about 65% of the sun blocked out. For details check out https://www.space.com/annular-solar-eclipse-2023-guide-ring-of-fire. Don’t forget your protective eyeware!!!!!

Until next month, Clear Skies! -Hank