For us Astro-geeks, the first sign that summer is on its way is the rising of the constellation, Cygnus the swan in the east. By mid-summer, this constellation is riding high overhead and is easily identifiable by the asterism it contains, the Northern Cross. At the tip of the northern cross is the second brightest star in the summer sky (Vega is the brightest) Deneb. If you have the luck to live under very dark skies, you will frequently see two fairly bright but nebulous patches of white clouds next to Deneb, these are the North American and Pelican nebulas. This particular photo was taken on the evening of July 25th from my backyard in Bedford, NH. It is a composite of 8 5 minute exposures taken through an ordinary unmodified canon 200mm f/4 L lens at with my modified canon 350d @ ISO 800. I used a deep red filter known as a hydrogen alpha filter for this shot and converted to greyscale.
The advantage to doing this is all the ambient skylight on the visual spectrum below the deep red of nebulas never makes it to the camera giving the photo a deep representation of the nebula. I will photograph this same object in color this summer and you will see the deep reds that I’m referring to.
