Spiral galaxy M74 with supernova

The bright Sc spiral galaxy NGC 628 (M74) in Pisces, from 4 minutes of red-light exposure in mornintg twilight, with a Tektronix 2048x2048 CCD at the 2.1-meter telescope of Kitt Peak National Observatory by Bill Keel and Lisa Frattare. North is at the top and east to the left, for direct comparison with a chart or eyepiece view. The image has been block-averaged by a factor of two for this presentation (and another factor of two as shown above), which uses a logarithmic intensity transformation to preserve information across a wide dynamic range. The field is 9.1 arcminutes square.

This is an excellent example of the subtype dubbed Sc(s) in the de Vaucouleurs extension of Hubble's galaxy classification, in which the arms arise in a spiralling pattern from the nuclear region itself rather than from a surrounding ring. I heartily recommend viewing the Gemini-North image to appreciate the wonderful structure of NGC 628. This image was taken on June 20, 2003, when the type II supernova 2003gd was bright; that's it almost due south of the nucleus in the bright spiral arm 2/3 of the way to the bottom of the image. It becomes clear on comparison with the color-composite BVR image below, which was done with the 1-meter SARA telescope on Kitt Peak during the 2013 Live Astronomy event at DragonCon.

I tried this one on two successive nights from the Lowell Observatory 1.1-m, with the comparison giving a good example of average versus poor atmospheric seeing.

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