March 2021

AP Corner - April 2021

Original article appears in GuideStar April, 2021.

A picture containing text, outdoor object, night skyDescription automatically generatedImage Capture Workflow

By Don Selle

This is the first in a series of “how-to” articles to help beginners learn astrophotography. The series will assume that long exposure imaging will be done through an OTA on a GoTo telescope mount that can be polar aligned. The camera attached to the OTA is either a cooled dedicated astronomy camera or a DSLR attached at prime focus. Since there are so many combinations of specific equipment the articles will assume that the telescope and camera have been set-up, equipment connected to a computer, powered up and checked out.

Most beginning astrophotographers (me included) were inspired by the work of others to jump into the hobby, not realizing how involved creating those beautiful pictures can be. No matter how much you know about daylight photography or how technically inclined you are when starting out, learning astrophotography can seem like a huge steep hill to climb.

If you can develop a consistent imaging workflow, a series of steps that you follow each time you go into the field, your astrophotography experience will be much more pleasant and productive. In this column we will explore at a high level the steps involved in a typical imaging workflow. Over the next several columns, we will take each of the steps and dig into them in more detail. So, let’s get started.

Remembering Leland Dolan - 1932 - 2021

Original article appears in GuideStar April, 2021.

Leland Dolan.jpg

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:

Watch the Lion: Celestial Wonders in Leo

Original article appears in GuideStar April, 2021.

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Watch the Lion: Celestial Wonders in Leo

by David Prosper

 NASA Night Sky Notes

Leo -NSN.jpg

The stars of Leo: note that you may see more or less stars, 
depending on your sky quality. The brightness of the Leo Triplet 
has been exaggerated for the purposes of the illustration.
You can’t see them with your unaided eye.

Leo is a prominent sight for stargazers in April. Its famous sickle, punctuated by the bright star Regulus, draws many a beginning stargazer’s eyes, inviting deeper looks into some of Leo’s celestial delights, including a great double star and a famous galactic trio.   

Leo’s distinctive forward sickle, or “reverse question mark,” is easy to spot as it climbs the skies in the southeast after sunset. If you are having a difficult time spotting the sickle, look for bright Sirius and Procyon - featured in last month’s article – and complete a triangle by drawing two lines to the east, joining at the bright star Regulus, the “period” in the reverse question mark. Trailing them is a trio of bright stars forming an isosceles triangle, the brightest star in that formation named Denebola. Connecting these two patterns together forms the constellation of Leo the Lion, with the forward-facing sickle being the lion’s head and mane, and the rear triangle its hindquarters. Can you see this mighty feline? It might help to imagine Leo proudly sitting up and staring straight ahead, like a celestial Sphinx.

Field of View - April 2021

Original article appears in GuideStar April, 2021.

Diamond Ring .jpg

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.

Messier Column - April 2021

Original article appears in GuideStar April, 2021.

By: Jim King

M44.PNGThe sucky winter, hopefully, is behind us.  During the past couple of weeks, we have had some nice weather and a couple of really good nights for observing.  We now get to move into the Messier early spring portion of his catalogue.

A TRIBUTE: Charles Messier passed on April 12, 1817, at the ripe old age of 86.  During his lifetime, he suffered through the French Revolution and was reduced to poverty.  He was finally restored to prominence as a member of the Academy of Sciences and Bureau des Longitude, after the revolution had run its course. Ironically, Messier wanted to be known for his list of cometary discoveries, but ultimately his list of objects that were not comets earned him immortality.

M44 Open Cluster (2) Easy

Cancer is the only constellation whose brightest stars are fainter than a Messier object within its boundaries.  In fact, if it were not for the mystifying cloudy appearance of open cluster M44, which draws your gaze to the surrounding 4th-magnitude stars, it is conceivable that dim Cancer might have been overlooked by ancient stargazers or possibly envisioned differently.  To the naked eye, the 3rd-magnitude glow of M44 looks like the bearded head of a tailless comet. 

Messier notes: (Observed March 4, 1769) Cluster of stars known as the nebula in Cancer.

NGC note: None                    Data: Messier 44 aka NGC 2632

Con: Cancer                           Mag: 3.1    RA: 08h40.4m           Dec: +19.40         Dist: 577 ly

Shallow Sky Object of the Month - April 2021

Original article appears in GuideStar April, 2021.

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

By Will Sager

Zodiacal_Light_Seen_from_Paranal.jpgSome 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.

Challenge Object - April 2021

Asterisms – Brosch 1, Virgo Diamond

Original article appears in GuideStar April, 2021.

By: Steve Goldberg

Asterism: a grouping of stars that form a recognizable pattern.
Constellation: Virgo                       
Right Ascension:  12h 33m 19.0s
Declination:  -00° 38' 42" Magnitude:  11 to 13
Size: 42”

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



Shallow Sky Object of the Month: Kappa Cas, SAO11256

Original article appears in GuideStar March, 2021.


by Bill Pellerin


Kappa Cassiopeiae and its bow shock. Spitzer infrared image (NASA/JPL-Caltech)

Object: Kappa Cas
Class: Fast moving Star
Constellation: Cassiopeia
Magnitude: 4.17
Speed: 2,500,000 miles/hr = 694 miles/sec
R.A.: 00 h 33m 00 s
Dec: 62 deg 55 min 54 sec
Size/Spectral: B
Distance: ~3500 ly
Optics needed: Unaided eye

Why this is interesting

This star shows up in the GCVS (the General Catalog of Variable Stars), but it isn’t very variable. AAVSO members have reported the star as dim as 4.25 and as bright as 3.8, but that’s not why it’s interesting.

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