M31

Spiral Galaxy in the Constellation Andromeda
With Companion Galaxies M110 and M32

Messier 31 (M31, NGC 224) is 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), our Milky Way and its companions, M33, and others.  At modern times, the Andromeda galaxy is certainly the most studied "external" galaxy. It is of particular interest because it allows studies of all the features of a galaxy from outside which we also find in Milky Way, but cannot observe as the greatest part of our Galaxy is hidden by interstellar dust. Thus there are continuous studies of the spiral structure, globular and open clusters, interstellar matter, planetary nebulae, supernova remnants (see e.g. Jeff Kanipe's article in Astronomy, November 1995, p. 46), galactic nucleus, companion galaxies, and more.  The Andromeda Galaxy is in notable interaction with its companion M32, which is apparently responsible for a considerable amount of disturbance in the spiral structure of M31.  Computer simulations have shown that the disturbances can be modeled by a recent close encounter with a small companion of the mass of M32. Very probably, M32 has also suffered from this encounter by losing many stars which are now spread in Andromeda's halo.  The Andromeda Galaxy is 250,000 light years in diameter and lies at a distance from Earth of 2.9 million light years, so it is more than twice as large as our own Milky Way galaxy.

Image Information  Courtesy of SEDS.

Image Details:

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  • Instrument:  Takahashi FCT-150 Flourite Triplet Apo Refractor with Takahashi Reducer/Flattener @ f/5.0 focal ratio (525mm effective focal length).
    Mount:  Paramount ME by Software Bisque
  • Image Scale:  2.47 arc-seconds per pixel
    Camera: SBIG STL-11000M Large Format CCD Camera with Astrodon Gen. 2 LRGB Filters 
    Filters & Exposure Times:
    • L:   9 x 15 minutes binned 1 x 1
    • R:  4 x 15 minutes binned 2 x 2
      G:  4 x 15 minutes binned 2 x 2
      B:  4 x 15 minutes binned 2 x 2
    • Multiple Luminance Layering in Photoshop (technique as described by Rob Gendler)
    • Total equivalent unbinned exposure time of 8.25 hours
    Software: CCDSoft Ver. 5, CCDStack, Adobe Photoshop CS2, RC Astro Gradient X-Terminator
    Location:  New Mexico Skies, Mayhill, NM.  El. 7250ft
    Date: October 28th, 2011

Wade Van Arsdale
Little Rock, AR., USA
November 8th, 2011

Earlier Mosaic Shot from 2007 With Stellarvue SV80S Refractor

Image Details:

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  • Instrument: Stellarvue SV80S Triplet Apo Refractor OTA @ f/5 (402mm, using Televue TRF-2008 0.8x Field Flattener)
  • Mount: Mountain Instruments MI-250 GoTo
  • Image Scale:  3.93 arc-seconds/pixel
  • Filters:  Baader IR Cutoff Filter
    Exposure: 18 x 5 minutes
  • Camera: SBIG ST-2000XCM Color One-Shot
    Notes:  This is a mosaic of two frames, using the Mosaic tool in Maxim DL/CCD software
  • Software: Maxim DL/CCD, Adobe Photoshop, RC Astro Gradient X-Terminator, Neat Image Pro
  • Location: Little Rock, AR., El. 300ft
  • Date: January 9th, 2007 0345