Welcome to Houston Astronomical Society

Founded in 1955, Houston Astronomical Society is an active community of enthusiastic amateur and professional astronomers with over 60 years of history in the Houston area. Through education and outreach, our programs promote science literacy and astronomy awareness. We meet via Zoom the first Friday of each month for the General Membership Meeting and the first Thursday of the month for the Novice Meeting. Membership has a variety of benefits, including access to a secure dark site west of Houston, a telescope loaner program, and much more. Joining is simple; you can sign up online, by mail or in person at a monthly meeting.

Membership Renewals and New Member Adds on Hold

Hello all,

We’re almost done with our website migration, so to make sure we transition everything over properly, we’re putting all membership renewals and new member processing on hold until January 9. Editors note: A number of members are testing the renewal process and the new member joining process. Please bear with us as we get through the migration. We will announce when you may renew your membership when the migration is over. Thank you very much for your cooperation.

Regards,
Joe Khalaf
HAS President

February 02, 2023, 7:00PM: February 2023 Novice Meeting via Zoom

"Putting your Observing in Context"

by Chris Morisette

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“As novices our early efforts are spent trying to find then admire objects of interest in the night sky.  Inevitably we start asking… what exactly am I looking at, how did it get there, and where is it with respect to us and everything else?  In “Putting Your Observing into Context” we’ll perform a brief survey of the Universe exploring the processes and structures that define the cosmos.”

Our Speaker: Chris Morisette is HAS Novice Chairperson and is also an active member of the North Houston Astronomy Club and the Fort Bend Astronomy Clubs.  He is also a member of the University of Texas Astronomy Department Board of Visitors and is a regular volunteer at the George Observatory.

February 03, 2023, 5:00PM: February Regular Meeting - Online via Zoom

Cosmology: How we know what we know about how the Universe works

With: DR. Niv Drory

McDonald Observatory / Dept. of Astronomy
The University of Texas at Austin

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Abstract –  50 years ago we had a theoretical framework, General Relativity, to explain what cosmologies are possible, but little data to tell us what the universe really is like. Today cosmology is a precision science with most of the fundamental quantities known to percent level precision. What has enabled this progress and what data are the bedrock upon which our detailed knowledge of the science of cosmology is built? What questions remain open, and what will future data be able to tell us?

Our Speaker – Dr. Niv Drory  – Niv was born in Israel, obtained a PhD in Physics at the University of Munich, Germany, writing his thesis on the first wide-field near-infrared survey of distant galaxies. He came to Texas for the first time as a Humboldt Fellow in 2002, where he joined the early work on Hobby Eberly Telescope Dark Energy Experiment (HETDEX). Niv has been a research staff member of the Max-Planck Institute for Extraterrestrial Physics (MPE), and spent 2 years as a Professor of Astronomy at the National Autonomous University of Mexico (UNAM). He is interested in Galaxies, Cosmology, and Instrumentation. He returned to Texas in 2013 to work on the HET Wide-Field Upgrade and HETDEX, and is now a Senior Research Scientist at McDonald Observatory. He is also deeply involved in the Sloan Digital Sky Survey as Instrument Scientist for MaNGA in SDSS-IV and PI of the Local Volume Mapper in SDSS-V.

Light Pollution: New Report Shows It’s Worse Than We Thought

By Will Sager

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Every astronomy enthusiast knows about light pollution, especially those of us under the Houston light dome. We watch our skies and get the feeling that the sky gets brighter as development grows apace. Using data collected by citizen scientists, a team of researchers from Germany and the US reports in the journal Science (Kyba et al., 2023) that light pollution is growing faster than previously thought. </p>

 

Ramp Up Your Game

by Jim King

Many, maybe most of you, have at least dabbled in the famous Messier Catalogue as a good deep-sky starting point for your observing efforts.  The problem with Charlie Messier is that his catalogue has as a primary purpose, the identification and location of objects that looked suspiciously like comets through his 3.5-inch telescope.  After all, he was a world-renowned comet chaser. He did not want to waste his time looking at/for things that looked like, but were not, comets.

Comes the NGC/IC catalogues.  The New General Catalogue of Nebulae and Clusters of Stars (NGC) is an astronomical catalogue of deep-sky objects compiled by John Louis Emil Dreyer in 1888.  The NGC contains 7,840 objects, including galaxies, star clusters, and nebulae. Dreyer published two supplements to the NGC in 1895 and 1908, known as the Index Catalogues (IC) describing a further 5,386 astronomical objects.  Thousands of these objects are best known by their NGC or IC numbers, which remain in widespread use.
13,226 is a bunch of objects, many of which are low on the exciting scale or are just plain not visible in backyard telescopes.  However, some are quite spectacular and we can all enjoy them with reasonable glass and viewing conditions.  The following list contains a small group of the best NGC/IC objects easily visible in late winter.

 

In Good Company: Leland Dolan

In Good Company: Leland Dolan

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In good company, you are, as you spend your time here with members. Here is one: Leland Dolan. Leland stayed with us a long time but he had to go away to where we all will go one day. Leland thought highly of us, has left a gift for us.

Let us be worthy. Let us continue this endeavor.

Thank you, Leland.

 

A Midsummer Astronomer’s Daydream, featured in this edition, was written by Leland.

Read more about Leland Dolan

A Midsummer Astronomer’s Daydream

By Leland A. Dolan

(From the September, 1987 issue of the GuideStar)

Perhaps one reason I was picked as historian, is that I tend to dwell a lot on the past. I still think of my early years as an amateur astronomer as the “good old days”. The chief difference between, say 1960 and now, is that I could observe a number of Messier objects from my yard, and yet I lived only a quarter mile from the University of St. Thomas. For observing or photographing the Milky Way, I would spend the night at my parents’ home, only a couple of miles west of Memorial Park. Nowadays, to go anywhere where one can observe deep sky objects, requires that two or three hours be spent traveling to and from the observing site.


But, Let’s take a look into the next century. No this article is not going to be a “downer” but an imaginary view of what might be possible in the future. WARNING: This article is perhaps outrageously speculative, and will not appeal to the hard-bitten realist. But, for those who like to dream, dream along with me.

 

GuideStar Cover February 2023

photographer: Don Selle

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Nightscape

Madison River and National Park Mountain - Yellowstone National Park

 

Getting You Exposed Part 2: AP Corner

By Don Selle

230127km_getting1.jpgPart 1 of Getting You Exposed, dealt with the concept of Total Exposure time and Exposure Value. It also provided some rules of thumb to help you estimate the Total Exposure time required for various types of targets using your own imaging rig. Having a good idea of the Total Exposure is certainly essential for acquiring high quality data on the low light level targets we image, but it is only one factor we need to consider.
Since most targets will require several hours of Total Exposure time to acquire enough data to assemble a quality image, we will typically acquire that data using multiple sub-exposures (aka sub-frames). The exposure time for each sub-frame when summed will equal the Total Exposure time of the acquired data. 
When you think about it, this makes sense. You wouldn’t want to take hours long single exposures as too much can happen. Satellite photo-bombs, mount tracking errors, autoguiding errors, operator error and things that bump your tripod in the night can ruin your sub-frames and result in the waste of a lot of time. Even back in the days of film, to avoid these risks, astro-imagers took multiple exposures, developed them, then scanned and electronically combined them to reduce the noise in the image.

 

Getting Started in Observing

by Steve Goldberg

When I first started out observing sometime in late 1960’s, some friends and an astronomy lab instructor pointed out some objects using my school’s 12” that was mounted on top of the science building. But the thing that they did not show me were the fundamentals of observing. It was sort of like telling you to get in a car and drive to Dallas without telling you what stop signs, and the brake pedal and police cars are. You must learn these before you can start going places. Observing is not that much different. Here are a few things that, when time is invested at the beginning, will pay back many dividends when at the eyepiece.

  1. One of the first things to learn are the constellations. Not all of them (you can’t see all of them from Houston) but the brighter ones. Constellations like Orion, Ursa Major and Minor, Scorpius, Virgo Hercules (that’s a tough one) and the brighter ones in the Zodiac. The constellations that have bright stars. Don’t waste your time yet when all the stars in a group can’t be seen from the city.
  2. Learn how to read star maps. Don’t get the kind that have so many stars in a small area of the sky on the biggest sheet of paper. Get the more condensed maps such as the Mag 5 or Mag 6, or the Pocket Sky Atlas. As time goes on you will eventually get the Sky Atlas 2000 or Uranometria and then on to the Palomar Observatory Sky Survey.

 

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