by Jim King

This is the first installment of a series of columns revolving around observing the Messier Catalogue.  The intent is to provide the reader a small sampling of the Messier objects that are most visible in the time frame the column is published.  Hence, these objects should be easily identifiable in and around the month of February and early March.

M1: The Crab Nebula.  The Crab was formed in July 1054, when its progenitor star blasted away most of its mass in a supernova explosion.  The event was recorded in several locations around the globe, but there are no known European references to the explosion.  It is still expanding at a rate of over 600 miles per second…almost 50 million miles per day!  Although created by an event similar, but more violent than that which creates a typical planetary nebula, the Crab does not have a typical planetary nebula’s form.  It is classed instead, as a supernova remnant.  The Crab’s pulsar rotates at 30 times per second.  First identified by John Bevis in 1731.

Object: Messier 001, aka NGC 1952, aka The Crab Nebula
Type: Supernova Remnant             
Con: Taurus
RA: 5.34.5   Dec: +22.01   Mag: 8.4  Dist: 6,500 ly
Opt view (February) 08.00pm. Very bright, very large, extends roughly along position angle 135 degrees; very gradually, a little brighter in the middle, mottled.

M103: One of the less notable open clusters in Messier’s Catalogue, it was originally identified by Mechain in 1781.  Challenge: it has a definite fan shape as do two other open clusters in Cassiopeia, M52 and NGC663.  See conflict below.  This the last object listed Messier’s original catalogue.  Numbers 104 through 110 have been added in recent years on the basis that Messier did observe them and that they would have been included had another Messier supplement been published.

Object: Messier 103, aka NGC581
Type: Open Cluster     
Con: Cassiopeia
RA: 01.33.4    Dec: +60.39.5
Mag: 7.4   Dist: 8,130 ly
Opt view (February) 07.30pm
Conflict: NGC663 has an appearance like M103.  NGC 663 also shows well in a finder scope, while M103 may not show at all.  Instead, M103 appears as three small stars.  NGC 663 is frequently mistaken for M103.  M103 is smaller, more compact and has a more regular fan shaped outline than NGC 663.

M042:  a nebulous star cluster in Orion.  Messier certainly did not “discover” this prominent naked-eye object; but he did determine its exact position, along with M43, M44, and M45 in March of 1789.  M42 is possibly the most rewarding deep sky object for a telescope of any size.  It has a wealth of eye detail and shows some color in a telescope of moderate aperture.  A prominent feature is the Trapezium, a bright, compact cluster of four stars in the shape of a trapezoid within the nebula. 

Object:  Messier 042, aka NGC 1976
Type: Emission Nebula and Cluster
Con: Orion
RA: 05.35.4   Dec: -05.27
Mag: 3.7   Dist: 1,500 ly
Opt view: (February) 7:52pm
True eye candy…perhaps the best in the northern hemisphere.  Do not be in a hurry.  Take your time and savor the view.

Notes from the Editor

Don Selle

Welcome to the March 2020 issue of the Guidestar, the award-winning monthly newsletter of the Houston Astronomical Society.  If you take the opportunity to check out the Guidestar issues that are archived on our website, you will see that there is almost 20 years’ worth of back issues available to download. That is only part of the story, since the Guidestar has been in publication almost as long as HAS has existed. It has been, and I hope it will continue to be the primary means by which we communicate, enlighten and nurture a community of amateur astronomers in the greater Houston area. ...

by Stephen Jones

In my personal opinion, the greatest benefit of membership in HAS is the access to our Dark Site.  One thing I see so often on astronomy forums is people like us who live in urban areas talking about the things they have to deal with when trying to do astronomy from dark locations.

Things like needing portable power packs, to dealing with critters, local law enforcement, or even yokels with guns.  On top of this, many of these people, especially in the Northeast, have to drive for 3+ hours just to get to a site decently dark enough for deep-sky astronomy.  How fortunate we are that we don’t have to deal with any of these things.  

The HAS Dark Site is an hour or less from parts of the West side of the metro area and no more than 2 hours from the furthest reaches of the East side.  It has all of the amenities you need for observing: solid ground to set your scope on, electricity, restrooms, bunkhouses to sleep in, a legal right for you to be there, and no one waving a gun in your face (critters can be a wild card, but they tend to stay away too).  There’s even telescopes you can borrow out there.  There are also all kinds of great events going on at the Dark Site throughout the year, like the Messier Marathon, Annual Picnic, and other great events put on by Jim King, our Field Trip and Observing Chair, as well as my Novice Lab program.

But there’s also no need to wait for an event to get out there!  Remember, your membership gets you 24-7 access to the dark site (with completion of the orientation, of course).  If the conditions are good there’s bound to be someone out there.  If you’re still worried about being there by yourself, connect with other members! Several folks, including myself, will frequently post to the email server or to the Facebook group when we are heading out there.  Feel free to send a post out there yourself if you’re thinking of going.

Also, please note, if there IS an event going on at the site, you’re not required to participate in it just because you’re at the site.  The event does not close the site off to folks exercising their right to use it.  If you’re not interested in attending my Novice Lab, for example, but you’d prefer to make your first trip to the site on a night when I’m there in case you have any issues, well then go ahead and come on my Novice Lab night and just do your own thing.  Nothing wrong with that at all.  

If your interest in observing extends beyond the moon and bright planets, dark skies are more important than any piece of equipment in your arsenal.  Thanks to the HAS Dark Site, getting those dark skies is a lot cheaper than your equipment too.  Get on out there and explore the universe.  

Clear Skies,
Stephen Jones
Vice President, Houston Astronomical Society

Editor's note: Recent sky quality meter readings at the Dark Site show 21.34 & 21.42; that's Bortle 3. Yes, we still get nights like that so keep your “to go bag” ready with your go-to and get to the dark site.

It gets cold outside observing. Warm up with a cup of coffee, hot chocolate, or tea at the Dark Site in front of the Dob shed. I’ll open up the hot beverage bar on clear third quarter and new moon Saturday nights; for March that’s 3/14, and 3/21. FYI, during third quarter, the moon does not rise until after midnight. During new moon, we don’t see the moon at all during the night time hours. So review the light rules, pick out your spot on the field, and when it’s cold, share some conversation over a hot brew at the Dob shed. —Rene Gedaly, membership@astronomyhouston.org