M33 - Widefield

Date: 27/01/08    Time: 1930hrs   Location: Sunningwell   Temperature: 5.8ºC  Relative Humidity: 77%

Camera: Nikon D80    Scope: William Optics Z66 Apo Doublet at prime focus   Mount: piggy-backed on Meade LX90 in equatorial mode  Exposures: 10x 90 seconds  ISO: 1600   F ratio: 5.9   Guidance: Autoguided

After a long period off my balcony and away from my telescopes due to ill-health, a wonderful opportunity on a Sunday night presented itself - low relative humidity, no sports-club lights on the horizon and the moon well into the final quarter and therefore not due to rise before midnight.  Coupled with the freedom of a Sunday afternoon to get set up in daylight, I reminded myself of the immense satisfaction of surveying the sheer beauty of our heavens as our late Winter constellations arced overhead.  Once again, the relatively small aperture of my new apochromatic refractor from William Optics poses  no obstacle to catching the spiral details in M33, our local group galaxy between Triangulum and Pegasus - now setting early in the evening as Spring fast approaches.  More detail of the outer arms and nebulosity would have been captured if I'd been brave enough to make the exposures longer - up to 180seconds each time.  The reason for not doing so was because when I had done this in the past, the light pollution seemed to obliterate the exposure with its orange glow - the difference on this night was the absence of the sports-ground lights (Tilsley Park - that abomination of urban planning) and the low relative humidity making seeing exceptionally good for these parts.  (See also the second attempt at M45 - Pleiades - taken on the same night with longer exposures).  The field was not entirely flat but the image above is cropped so the edges are not seen with elongated stars, dark-subtraction was carried out by the Nikon built-in noise-reduction process.  10 frames were stacked using Maxim DL, light pollution glow was subtracted in Photoshop, followed by the usual white and black point setting and midtone enhancement.  

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