October DAS Focus

COMPUTERS IN ASTRONOMY by Don Shedrick

The October DAS meeting feature program will be on "Choosing a Telescope" by Emil Volcheck. With the holiday buying season closing in like a speeding comet, this is an appropriate topic. This month, I will highlight some web sites that the astronomy equipment shopper can use to learn about equipment, performance reports, manufacturers’ web sites, and equipment suppliers.

Astronomy-Mall.com at: http://www.astronomy-mall.com/ lists dozens of manufacturers and suppliers of telescopes, and accessories. A site very similar to Astronomy Mall is Astromart at: http://www.astromart.com/.

The largest telescope manufacturers are Meade and Celestron. Their web sites are at: http://www.meade.com/ and: http://www.celestron.com/ respectively. The Celestron site has a very nice primer on telescope basics at: http://www.celestron.com/tel4ast.htm covering many aspects of telescope types, optical characteristics, accessories, and usage.

Orion Telescopes and Binoculars is a very popular mail order catalog company, with a web site at: http://www.telescope.com

They have a vast selection of everything in astronomy equipment, as well as books and software. The web site has a very complete "Learning Center" at: http://www.telescope.com/content/learningcenter/learningcentergatewaymain.jsp?iCategoryID=19&CCNavIDs=19 with dozens of articles covering choosing a telescope, observing, photography, and optics. There is also a link to "What’s in the Sky Tonight" at:

http://www.telescope.com/content/inthesky/content5main.jsp?KickerID=28&KICKER

including a link to hear the daily StarDate (http://stardate.org/) astronomy program for radio, produced by the University of Texas MacDonald Observatory, and a sky summary and star map for the current month provided by Abrams Planetarium. This is a useful site you should bookmark for frequent use.

Now, to focus in on the most important telescope accessory, Ken’s Eyepiece Corner at: http://www.klhess.com/teleindx.htm has specifications of leading eyepieces listed by manufacturer, a listing of manufacturers with web site links, and an eyepiece calculator. This calculator takes the objective diameter, f ratio, focal length, eyepiece apparent field, and eyepiece focal length to calculate the estimated objective performance, telescope magnification, magnification per inch, true field, and exit pupil size. It is a great way to compare the characteristics of different eyepieces and how they will perform in your telescope.

Televue, another major telescope manufacturer, has an interesting article on their web site written by their founder, Al Nagler. Located at:

http://www201.pair.com/resource/astro.html/regular/products/tele-vue-optics/pg4.htm

this article, titled "Choosing Your Telescope's Magnification", describes factors that determine the magnification range to use on a given night with a given telescope. This can help in choosing eyepieces best suited to your needs.

If at this point you would like a little diversion from your shopping, surf over to the NASA web site that explains why we need different types of telescopes to look at outer space, with history and descriptions of radio, infrared, visual, X-ray, and gamma ray telescopes. This web site is at:

http://science.nasa.gov/newhome/headlines/features/ast20apr99_1.htm

Now, if you know what type of equipment you want, but would like some more info on how it might perform, there are some web sites that give performance reviews on various astronomical equipment. Sky and Telescope magazine has equipment reviews from past issues on their web site at:

http://skyandtelescope.com/resources/testreports/

The Telescope Review Web Site By Ed Ting at: http://www.scopereviews.com/ is one of the most comprehensive and popular telescope review web sites on the Internet. Inside, you will find high quality, detailed reviews by this amateur of over 80 telescopes, eyepiece reviews, a beginner's advice column, feature articles, links, and even a review of an astronomy Bed and Breakfast Inn!

Todd Gross’ Equipment Talk web site at:
http://www.weatherman.com/wxastrob.htm is another quality amateur review site that contains his equipment reviews of over 60 scopes, plus many links to other amateur review sites.

For this month’s cool web site of the month, we go to Science at NASA:

http://science.nasa.gov/

This site has recent headlines and articles on everything to do with space from space weather to origins of life. You can sign up to have Science at NASA notify you via e-mail messages of their latest science headlines as soon as they appear on the site. This site is sponsored by the Science Directorate at NASA's Marshall Space Flight Center in Huntsville, Alabama.