Galaxy Groups & Clusters Introduction

Galaxy Groups and Clusters Program Coordinator:

Dareth Murray
5718 SE Harlow Street
Milwaukie, OR 97222


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Welcome to the Astronomical League's Galaxy Groups and Clusters Observing Program. This program of 250 galaxy groups and clusters is designed for detailed visual and/or CCD observation.

For many, the challenge will be to see these galaxy clusters with their own eyes. Most of the galaxy groups and clusters of this observing program are visually accessible with a 12.5" telescope, although there are individual galaxies in some of the groups that are beyond almost all amateur observers. Although this program accomodates CCD cameras and imagers, you don't need a CCD camera to complete this program. You will be able to see at least some galaxies in all of the groups.

There are several rewards for undertaking this program, no matter which method you choose. Subtle visual detection will reward you with the thrilling experience of viewing extremely distant objects at the very edge of visibility. In a CCD image, this same cluster may be a very beautiful cloud of galaxies and their dim clouds of globular clusters.

Learning to identify star fields is important even with a computer driven telescope. An observer must match the galaxies with their map coordinates. Many of the clusters in this program's catalog are dim and difficult objet to find, requiring the observer to star hop and use averted vision.

Galaxy Groups Club LogoTo obtain your certificate and award pin for this program, purchase the Observe Galaxy Groups and Cluster observing guide from the AL Bookstore specifically written to support this observing program.

This guide is for amateur astronomers wanting to view and/or image galaxy groups and cluster visible in amateur telescopes. It contains a variety of associations from small compact groups, to larger, less compact groups (in some cases not well isolated from other nearby galaxies). Due to the nature of these complex objects, it is impossible to set a definite magnitude limit for this guide. In this sense, the challenge is open ended. Try to observer as many galaxies as you can in each case and don't be afraid to push your limits. You may be surprised to find that seemingly impossible faint objects will often yield to persistent scrutiny.

This guide includes a brief overview of some of the most popular atlases to assist you with their use and content. You will also find a variety of helpful observing hints, techniques, coordinates, data and technical information.


Rules and Regulations

There are two categories of search methods for this program, Manual and Device-Aided. To be considered for the Manual certificate, ALL of the objects must be observed manually. A space is provided on the Submittal Form to indicate your search method.

Manual infers that the observer hand-guides the telescope to the object. The observer uses his/her eye to see through the telescope to navigate to the object. Device-Aided infers the observer uses manual or digital setting circles, computer devices or other automatic aids in locating the object.

There are also two types of observing techniques, visual and imaging. Visual infers that the object is observed with the eye through the optics of the telescope. Imaging infers observations are obtained using astrophotography and/or CCD techniques.

To qualify for the AL's Galaxy Groups & Clusters Certificate and pin, you need only be a member of the Astronomical League, either through an affiliated club or as a Member-at-Large. If you are not a member now, click here to view information on becoming a member.

Of the 250 objects listed in the Galaxy Groups & Clusters Guide, you must observe 120 objects: 1) 30 Galaxy Trios; 2) 30 Hickson compact galaxy groups; 3) 30 Additional Galaxy Groups; and 4) 30 Abell galaxy clusters. Record your observations on the form provided in the guide.

Write object descriptions that will include at a minimum:

  • Date
  • Time (specify local time zone or Universal Time)
  • Site (name site and include approximate latitude, longitude and elevation)
  • Seeing (describe on a scale; indicate which scale you are using)
  • Transparency (give naked eye limiting magnitude or specify an alternate scale)
  • Averted vision level if applicable (rate according to an averted vision scale)
  • Instrument (include information on telescope, eyepieces, CCD cameras or other instrumentation)
  • Description, in your own words, of the group and individual galaxies as appropriate (in many cases you will probably only see a very faint smudge).

Complete an index by putting the page number of your descriptions next to the groups and clusters on the list. The check-off and date columns are for your own use.


Submitting for Certification

To receive your Galaxy Groups & Clusters Certificate and Award Pin, complete the Submission form (found in the Guide), along with a copy of your observations, to:


Galaxy Groups and Clusters Program Coordinator:

Dareth Murray
5718 SE Harlow Street
Milwaukie, OR 97222

Upon verification of your observations, your certificate and award pin will be sent to you or your society's Awards Co-ordinator, whomever you choose.



Find Your Galaxy Groups and Clusters Program Award