Constellation - Canes Major
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Here was my second attempt at photographing a constellation. This was my first attempt while having my camera mounted on an old telescope mount that tracked with the sky. This allowed me to take long exposures without having star trails, which is why you can see literally hundreds if not thousands more stars than in my first attempt.
Post-processing was much easier this time, and I did it the same way that I did the deep sky processing from the previous week. I aligned the color channels, added the frames after dark-subtracting, and adjusted the levels and curves to bring out the stars and colors and suppress the sky glow due to a lack of flatfielding. I adjusted it until I got approximate true-color back. Then I duplicated the image, set the top layer mode to Screen, selected everything but M42, and did a Gaussian Blur. I then adjusted the levels to bring the blur -> glow up and that created the glowing stars.
There are two versions of the final image. One of them is annotated with the bright stars (in smaller font) and the deep sky objects that are visible in the image. There are deeper sky objects in the field of view, but they are not visible in this image due to the processing and and moon about a quarter of the sky away.
| Object | Constellation - Canes Major (And Surrounding Area) |
| Common Name | -- |
| Date, Time, & Moon | March 28, 2006; ?? |
| Location | SBO Telescope at CU Boulder |
| Optics | 43 mm lens; f/5.6 |
| Camera | Canon Digital Rebel 350D XT; ISO 100 |
| Exposure Time | 941 seconds total; 2 330-second exposures and 1 281-second stacked, plus a 120-second image with diffraction spikes |
| Optical Correction | Dark-Correction; no Flatframe-Correction |
| Camera Position | Normal Camera Lens |
| Guiding | Passive Clock Drive on Equatorial Mount |
| Processing Details | PhotoShop CS - Aligned and averaged color channels; Levels, Curves, and added star glow |
| Image Size | ?? |
| Magnitude Depth | ?? |
| Notes | Clouds moved into the field of view, which is the red towards the lower right, and there were several airplanes that flew threw the field. |