Flat Galaxies Program


Introduction & Overview


Detection of shape and form in galaxies is a visual challenge. As a general class of galaxies, edge-on galaxies are a pleasant yet demanding change of pace. A subclass of edge-on galaxies are flat galaxies which are defined as having a diameter larger than 40 arc-seconds and a major to minor axis ratio of >= 71. This unique brand of galaxies is used as a tool for studying large scale motions and distances. Karachentsev et al1 published the fact that there is a tight correlation between their linear diameter and the width of the 21cm line that can be detected. There are thousands of flat galaxies catalogued1,2 with many of them well beyond the limit of visual observations. The galaxies selected are brighter than 15th magnitude, with the majority well within the range of amateur telescopes.

Purpose & Significance

The purpose of this program is to provide a unique challenge for visual and imaging observers in both the Northern and Southern hemispheres. It is designed to hone the observer’s skills in finding, detecting, recording observations such as determining the PA (position angle) of flat galaxies. The objective is to provide a venue for the advanced amateur observer to become more familiar with this class of galaxy classification and begin to appreciate the ease or difficulty in detecting them. This observing program serves to consolidate as well as bring to light this unusual class of galaxies.

  • Requirements:
  • Observers will be required to observe any 50 flat galaxies from Appendix A (list is attached) for the Flat Galaxy Observer Regular Award and any 100 flat galaxies from Appendix A for Honorary Award plus the pin.
  • Observations will be telescopic and can be recorded either visually (V) or electronically/photographically (E).
  • The galaxies can be located manually (M), with digital setting circles or GOTO telescopes (D).
  • For Visual observations, log sheets should contain:
    • Latitude and Longitude of observation.
    • Sky conditions: transparency and seeing.
    • Telescope aperture and focal length.
    • Whether the object was found manually, with digital setting circles or a GOTO telescope.
    • Magnification
    • The Revised Flat Galaxy Catalogue (RFGC) number of the galaxy observed.
    • Observing details and descriptions.
    • Position angle of the Flat Galaxy (from 0° [North-South]– 179°
  • Photographic or digital imaging observations, the image:
    • Should have the estimated position angle (P.A.).
    • In addition, log sheets should contain:
      • Type of camera used.

 Rules for Completing the Program:

  • The log sheets and electronic files containing digital images (which should be submitted on a CD-ROM) should be sent to the program administrator. The observations will be verified by the program coordinator.
  • Eligibility for the Award:  AL members in good standing only.
  • Appendices:

Appendix A: a list of flat galaxies by Right Ascension (spreadsheet) (pdf)
Appendix B: a list of flat galaxies by constellation (spreadsheet) (pdf)
Appendix C: a list of flat galaxies ‘above -30°  Declination’ (spreadsheet) (pdf)


  1. Flat Galaxy Catalogue, Karachentsev, I.D., Karachentseva, V.E. and Parnovsky, S.L. Astronomische Nachrichten 313: 97-222, 1993.
  2. The Revised Flat Galaxy Catalogue, Karachentsev, I.D., Karachentseva, V.E., Kudrya, Y.N., Sharina, M.E. and Parnovsky, S.L. Bull. Spec. Astrophys. Obs. 47: 5-185, 1999.

 Members of the Delaware Valley Amateur Astronomers: John Bajtelsmit, Mark Huss, Vince Scheetz of who assisted in the development of this program and Dick Steinberg who imaged the flat galaxies used on the certificates.

Administration and Program Chair:
Al Lamperti
505 Ramsey Road, Oreland, PA 19075

Find your Flat Galaxies Program Award

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