March 2021

I first met Leland Dolan in the summer of 1959, when we both were in an astronomy class at the South Texas Junior College. It was there I learned about the Houston Amateur Astronomy Club (HAAC). The club met in the original Science Building at the central campus of the University of Houston. When several HAAC members formed a special interest group for amateur telescope making, Leland served as the SIG secretary.

Over the years there were pressures for a name change to the Houston Astronomical Society, and when that occurred, Leland assisted the By-Laws committee with his extensive knowledge of the club history and recollections of older members of the HAAC. He continued to help the membership in later years by providing observing aid printouts at the monthly meeting. He frequently highlighted news about recent astronomical events of importance, discoveries as well as the passage of the solstices, equinox events, and other phenomena.

For most of his 60 years of membership in the Houston Astronomical Society, Leland attended every monthly meeting. His loyalty to the HAS is memorable in its continuity. Most of the older members of HAS who knew Leland when he was younger and more active will miss his presence in our monthly meetings. I know I will.    Fred Garcia

Leland passed away at home with his family on February 27, 2021. His family has requested that those wishing to memorialize Leland may make a donations to MD Anderson Cancer Center at: https://gifts.mdanderson.org

By Don Selle – Guidestar Editor

The month’s Guidestar cover is a wonderful image by HAS member Don Taylor of the eclipse of August 21, 2017. I thought it was very appropriate image for the April cover because the next total eclipse to race across much of the USA will happen on April 8, 2024, and we are a little more than half-way timewise between the two events.

The 2017 event was dubbed the Great American Eclipse because the path of totality ran the entire length of the USA. From the Pacific Ocean, it crossed the Oregon coast, ran across the Rockies and Midwest, then exited into the Atlantic Ocean over the coastline of South Carolina. The build-up for the event was tremendous – practically everyone knew it was coming, and its summer date encouraged many (including me) to schedule family vacations planned for observing the eclipse.

False Twilight: The Zodiacal Light – Is it a Reflection of Mars?

By Will Sager

Some evenings it seems to take forever for the sky to get dark. Normally, we progress from sunset to civil twilight to nautical twilight to astronomical twilight to dark. The civil twilight occurs between sunset and the sun being 6° below the horizon, nautical twilight when the sun is between 6° and 12° below the horizon, and astronomical twilight from 12°-18° below the horizon. After astronomical twilight, the sky should be dark and remain so until astronomical twilight begins before dawn. But sometimes, especially in the spring and fall, the sky is brighter longer because of the Zodiacal light.

This phenomenon is attributed to the scattering of light by tiny dust particles in the plane of the solar system. It usually appears as a diffuse triangular region, broadest at the horizon and narrowing towards the zenith. Zodiacal light is dim enough that light pollution or the Moon’s glare will mask its faint glow. In clear, transparent skies with no light pollution, the Zodiacal light soars across the entire sky, with a slight brightening at the anti-solar point, where backscattered light causes a brightening called the gegenschein. In less perfect conditions, Zodiacal light is a brightening of the western sky after sunset or the morning sky before dawn, when it is called the “false dawn”. Although Zodiacal light can be seen on most dark nights, it is most prominent after sunset in the spring and before sunrise in the fall.

This asterism is located in Virgo. Starting with Spica, locate star Porrima Gamma γ VIRGO. This star is the “anchor point” for the semi-circle of stars in Virgo.

Just above a line from Porrima to Zaniah Eta η VIRGO, Brosch 1 can be located.

Brosch 1 is a square or diamond, depending on how it appears in your eyepiece. The object first appears as 4 stars. But looking closer, one of the stars is a double. See if you can split that double. Another name for this asterism is the Virgo Diamond, which is very descriptive.

Brosch 1 is named for Noah Brosch, an Israeli astronomer still doing research today. Here is Wiki info on Brosch.

Wiki Noah Brosch