Constellation - Leo
Click Images for Larger Version
After photographing Orion, I decided to move onto other constellations since Orion had set by the time I got to the telescope the second night.
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, 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), the deep sky objects that are visible in the image, and the astronomical constellations in large gray font. 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 third of the sky away.
| Object | Constellation - Leo |
| Common Name | -- |
| Date, Time, & Moon | March 4, 2006; 32% Full Moon |
| Location | SBO Telescope at CU Boulder |
| Optics | 24 mm lens; f/5.6 |
| Camera | Canon Digital Rebel 350D XT; ISO 100 |
| Exposure Time | 1600 seconds total; 4 400-second exposures stacked |
| Optical Correction | Dark- and 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 | approx. 52° 53' 29" by 35° 15' 39" |
| Magnitude Depth | Approx. 9th magnitude |
| Notes | I captured this soon before and while the constellation passed through the central meridian. This meant that light from Denver covered the lower left part of the image. Consequently, I darkened that section which is why it's black and devoid of stars in the above image. |