By Will Sager
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>
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, 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.
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.
photographer: Don Selle
Nightscape
Madison River and National Park Mountain - Yellowstone National Park
By Don Selle
Part 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.
Steve Goldberg
This is the start of a series of questions and answers for the HAS GuideStar newsletters. Originally authored by Amelia Goldberg in the 1980’s.
This month’s question is:
As you know the Moon goes through phases. If you were on the Moon, would the Earth go through phases? If no, why not? If yes, what would you call the names of the phases and is it in any way related to the Moon’s phases?
Answer next month.
UPDATE: What a great turnout! What great fun! Let’s do this again!
Saturday, Jan 14. Sunset 5:48 pm. Astro dark 7:12 pm. Moonrise 12:53 am (Sunday).
BYOP. Bring your own picnic: food to grill, or a picnic basket, or takeout, and a chair. I’ll be at the picnic area around 2:30pm to open up—come by and say hi! We’ll start shutting down around 4:30pm so we can finish setting up on the observing field by sunset.
BINO SIG. Bring your binoculars and chair and meet at the lawn sign. I’ll have printed sky maps, red flashlights, and clip boards for us to use.
Observatory. Comet C/2022 E3 is an early Sunday morning object. If the weather stays clear, I will have the C14 trained on it. Members, contact [email protected] to reserve a bunk in the family, women’s, or men’s bunkhouse.
Rene Gedaly, Field Trip & Observing
