M64: Blackeye Galaxy

 

RA: 12hrs 56min 42secs   Dec: 21º 41' 00"   Mag: 8.5   Distance: 20 million light years   Constellation: Canes venatici

This was a surprisingly gratifying image, given the relatively small size of the subject and low luminosity.  Already with an unusually short total exposure time, I was able to distinguish the large dust trail across the circumference of this distant spiral galaxy which gives it its unique name.  This was one of the photographs taken without the equatorial wedge and so exposures were limited to 15 seconds each to avoid too much rotational smearing of the star outline with the rotation of the field.  The photograph was taken on the 17th of June 2005 on a clear still night.

3 exposures of 13x15 seconds, 21x15 and 41x15 were taken giving a total exposure time of 18.75 minutes.  The raw images were combined in MaximDL and saved as an 8 bit tiff file.  In Photoshop, I stretched the histogram to enhance the contrast in each of the R, G and B channels, unfortunately losing a few dimmer stars in the process, in order to lose the borders of the stacked images which were otherwise visible.  Midtone enhancement was carried out using the Curves command but not before masking the central core of the galaxy to prevent over exposure and 'whiting out'.  (Feather=5)  Because of the high level of midtone enhancement required, some slight digital contouring appeared around the core of the galaxy and therefore Gaussian blur was applied (1.7 pixels) to smooth out the final nebulosity.  There was an expanse of black around the image and so the subject was cropped, hence the unusual aspect ratio of this photo.

Problems: Longer exposure time would have brought out more detail in the galaxy and required less midtone enhancement, but nevertheless, as a first attempt at a difficult object, this wasn't bad.

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