March DAS Focus

COMPUTERS IN ASTRONOMY by Don Shedrick

March is the time of year when young men and women’s thoughts turn to…..Messier Objects. Yes, it is the one time of year when, in an amazing coincidence, the objects it took Messier 24 years to observe and catalog can all be seen in one night. The Messier Marathon was invented (or discovered) independently by several amateur astronomers and clubs in the 1970's. To accomplish this feat, you must have excellent sky conditions and observing site, and a lot of patience. Michigan amateur Richard Bell has some tips on his web site at: http://my.voyager.net/stargazer/marathon.html

He includes a listing of the objects in the order in which they should be observed to maximize your efficiency through the night.

Messier Marathon is a SEDS (Students for the Exploration and Development of Space) site at:

http://www.seds.org/messier/xtra/marathon/marathon.html

with information on the years best observing opportunity around the New Moon in March. There are links to other sky objects to look for during the Marathon including planets, comets, and meteors, and satellites.

The Astronomical League Observing Clubs may be better suited for those of us who are not insomniacs. They offer encouragement and certificates of accomplishment for observing at your own leisurely pace and demonstrating observing skills with a variety of instruments and objects. Lynn King is our leader for any of the AL Observing Clubs. These include the Messier Club; Binocular Messier Club and the Herschel 400 Club, the Deep Sky Binocular Club, the Southern Skies Binocular Club, the Meteor Club, the Double Star Club, and the Lunar Club. Each Club offers a certificate based upon achieving certain observing goals. These are usually in the form of a specific number of objects of a specific group with a given type of instrument. There is no time limit for completing the required observing, but good record keeping is required, which is sent in for approval and receipt of your certificate. As a recipient of the binocular Messier and Lunar certificates, I can attest that the programs are an excellent way to learn the sky. The web site:

http://www.astroleague.org/al/obsclubs/obsclub.html

has information and log sheets for each observing program for download.

There are several good web sites for finding information on the Messier objects and locating them in the sky. The SEDS Messier Site at:

http://www.seds.org/messier/

is the mother lode of info on Messier objects. The site starts out with historical info on Charles Messier, and then has links to various listings of the objects.

The Messier Object Numerical Index has thumbnail images and links to several pages of info on each object and a sky map of the constellation in which it is located. This site is at:

http://www.seds.org/messier/data2.html

or a similar list with additional data (type, right ascension, declination, apparent visual magnitude, angular dimension, and distance in kilo-light-years) is at:

http://seds.lpl.arizona.edu/messier/data.html

You can also view the Messier objects organized by constellation at:

http://www.seds.org/messier/CONindex2.html

or by object type (nebula, cluster, galaxy, or other) at:

http://www.seds.org/messier/objects.html

The Twelve Months Tour is a monthly list of Messier objects for best viewing by Tony Cecce, a member of The Astronomy Connection, a network of active San Francisco Bay area observers. This list can be used to plan out your observing sessions. The site also features monthly Hershel Lists and other observing tools and info. It is at:

http://observers.org/observing/

Messier Finder Charts have been developed by Stephen Tonkin, a UK amateur and Fellow of the Royal Astronomical Society. He has two charts for Messier objects at:

http://www.geocities.com/sftonkin/messier/messchart.htm

1. An uninverted chart covering about 10° of sky, with a 5° circle, for use with binoculars

2. An E/W reversed chart covering about 5° of sky, with a 2° circle, for use with an SCT or refractor with a diagonal.
This reversed chart is hard to find, and very useful for users of these reverse image telescopes. If you like what you see, you can download all the charts to your PC. He also has very nice Messier Marathon Log Sheets in various file formats for download at:

http://www.geocities.com/sftonkin/messier/messlog.htm

I have saved the best charting program, Your Sky, for last. This was developed by John Walker, a formidable Swiss software engineer who founded Autodesk and co-authored AutoCAD. He wrote the Home Planet software previously featured in this column, which this web based software closely resembles. It is an interactive planetarium of the Web at:

http://www.fourmilab.ch/yoursky/

where you can produce maps for any time and date, viewpoint, and observing location. If you enter the orbital elements of an asteroid or comet, Your Sky will compute its current position and plot it on the map. Each map is accompanied by an ephemeris for the Sun, Moon, planets, and any tracked asteroid or comet. A control panel permits customization of which objects are plotted, limiting magnitudes, color scheme, image size, planetarium or horizon view, and other parameters. It even has a solar system orrery.

Your Sky's Virtual Telescope turns your computer into a software telescope of the web. Controls allow you to set time and date, aiming point, orbital elements to track an asteroid or comet, and a variety of viewing options, including actual field of view (magnification). You can compose a request with custom settings and save the results in your browser's bookmarks, allowing direct access to the virtual telescope with all the controls preset to your own preferences.

Your Sky Object Catalogs at:

http://www.fourmilab.ch/yoursky/catalogues/catalogues.html

links the names of listed objects to Your Sky's Virtual Telescope; clicking on the object will bring up a view of it in the Virtual Telescope and thus show you where it is in the sky. From there, you can use all the telescope controls to zoom in or pan, as well a select many other viewing options. Of course, the Messier Objects are one of the catalogs available at:

http://www.fourmilab.ch/yoursky/catalogues/messier.html

as well as others for Planets, Constellations, Selected Deep Sky Objects, Radiants of Meteor Showers, Navigation Stars, Named Stars, Periodic Comets, and Asteroids by Name or by Number.