Don Shedrick

 

 

 

 

 

Oct 4, 2001

October DAS Focus

COMPUTERS IN ASTRONOMY by Don Shedrick

As the summer sky with its many star clusters and nebula leaves us, we are now finding a sky with more galaxies to view. These demand a dark sky to easily view any but the brightest, but dark sky viewing sites are hard to find these days.

Phil Harrington has compiled a Dark-Sky Observing Site Directory at:

http://ourworld.compuserve.com/homepages/pharrington/Dssd.htm

This directory of constantly expanding continent-wide dark-sky observing sites lists dozens of observing sites in 28 states and three Canadian provinces, with new sites being added regularly. These sites have all been contributed by people who enjoy viewing the real universe, away from city lights and haze, including a description of the site and limiting magnitude. All sites are accessible by the public during the night, with few if any restrictions.

I have identified several web sites with info on galaxies and other deep sky objects, and lists of objects to observe.

An Introduction to Galaxies at:

http://www.xtec.es/recursos/astronom/hst/galintro.htm

provides a brief introduction to the types and structures of galaxies.

Galaxies at:

http://www.astro.uu.se/~ns/popgal.html

from the University of Alabama describes galaxies in detail, including information on the history of our understanding of galaxies, their classification, and the relationship of galaxies to topics like dark matter and cosmology.

The SEDS (Student for the Exploration and Development of Space) Organization featured previously in this column has several web pages with deep sky objects data.

The Andromeda Galaxy is by far the easiest to see (except for our own milky Way). The SEDS M31 web page at:

http://seds.lpl.arizona.edu/messier/m/m031.html

has abundant info on M31, the famous Andromeda galaxy, our nearest large neighbor galaxy, forming the Local Group of galaxies together with its companions (including M32 and M110, two bright dwarf elliptical galaxies), M33, our Milky Way, and others. This page gives the history and features of M31, and many related links including images.

The RASC's Finest N.G.C. Objects List is at:

http://seds.lpl.arizona.edu/messier/xtra/similar/rasc-ngc.html

The Royal Astronomical Society of Canada (RASC) has published this list of 110 finest N.G.C. Objects compiled by Alan Dyer, and is arranged and sorted by seasons and constellations.

Galaxies with Proper Names at:

http://www.seds.org/messier/xtra/supp/rasc-g-n.html

lists galaxies by their common name, such as "Black Eye Galaxy", so you can find the location and data for an object you heard the name of but have no other info for.

William Herschel's catalog of Deep Sky objects at:

http://www.seds.org/messier/xtra/similar/herschel.html

is available online as either The Astronomical League's selection of 400 Herschel objects, for which the AL grants the Herschel Award, or the full Herschel list of 2500 (actually 2514).

The Interactive NGC Catalog is online at:

http://www.seds.org/~spider/ngc/ngc.html

This is the interactive NGC (and IC, and Messier) catalog at SEDS, based on the NGC 2000.0 by R.W. Sinnott of Sky Publishing Corp. The NGC and its supplements IC I and IC II were originally compiled by J.L.E. Dreyer and published 1887 (NGC), 1895 (IC I) and 1907 (IC II). It contains open and globular star clusters (and some asterisms), diffuse and planetary nebulae, supernova remnants, galaxies of all types (and some knots in bright galaxies), and some erroneous entries corresponding to no objects at all.

You will get the NGC 2000.0 data for each NGC, IC, or Messier object. In addition, you get a link for downloading an image from the Digital Sky Survey for each object, as well as a link to the data of NASA/IPAC Extragalactic Database (NED), a link to the data of the SIMBAD Astronomical Database, a link to the Hubble Space Telescope (HST) Archive images for each object, and a link to the observing reports collected at the IAAC NetAstroCatalog. If available, you will also get a link to some descriptive HTML page, and an image of the object. All you need to do is type in the NGC, IC, or Messier number of the object you'd like to find.

The Deep Sky Database at:

http://www.virtualcolony.com/sac/

employs a web-based version of the Saguaro Astronomy Club's (SAC, from Phoenix, Arizona) database, consisting of over 10,000 records. This online version of the SAC database allows you to search and compile detailed and customized observing lists based on Galaxies and Galaxy Clusters, Open and Globular Clusters, Bright and Dark Nebulae, Planetary Nebulae, All objects within a Constellation, Unusual objects in the sky, The Messier Objects by Season, The Herschel 400 Objects by Constellation, The Herschel 2500 Objects by Constellation, and Double Stars by Constellation. Additional search criteria include object type, magnitude, major axis size, and choice of report sorting by right ascension, magnitude, surface brightness, Uranometria 2000 chart number or object catalog name.

The NGC/IC Observing List Generator at:

http://www.ngcic.com/oblstgen.htm

is provided by The NGC/IC Project. This Project is an attempt to correctly identify all of the original NGC and IC objects, starting with the original discoverer's notes and working forward in time to encompass the work of contemporary astronomers, both professional and amateur, such that the identity of each of the NGC and IC objects is known with as much certainty as possible from the existing historical record. The Observing List Generator is an online program that develops an observing list based on your input of such criteria as Constellation, Object Type, and Magnitude Limits.

And a final note with good news for all you surfers - these Computers in Astronomy articles are now being linked from the DAS Web Site:

http://www.cis.udel.edu/~case/das.html

so all you need to do is scroll down to near the bottom of the DAS web page, click on the link to the Computers in Astronomy article, and then you can access any of the referenced web pages in the article by simply clicking on the hot link for it in the article.