Aug 292011
 

Altair is a very bright star just under 17 light years away. It’ s one of the three stars of the Summer Triangle. It’s part of the “face” of the constellation Aquila the Eagle. It’s also the main subject of the first image taken with my new DSLR and then stacked, adjusted, and prettied up to look good.

Altair

Altair in Aquila and Delphinus

It might be hard to see in the image to the right, but if you click it and make it big, you’ll see big glowing Altair on the right side of the picture, with one bright star above (and a little to the right) and one bright star below (and a little to the left). (Ignore the “halo” around Altair – that’s the result of bad dew control.) These three stars make up the breast or face of the Eagle, Aquila. In the upper left, you can make out four stars in a diamond shape. with a sort of “tail” coming down on the right side. This is the constellation Delphinus, the the Dolphin.

All told, there are a lot of stars in this picture. This is the stacked summation of about 30 images, some better than others. The images were analyzed so that bright dots (stars) were tracked between the images. This then let the software register the images so that they all showed the same view with everything in the same spot. The images were then stacked so that about 25% of the images were dropped from the result for being of poor quality. The remaining images are combined to reduce noise in the final image. Less noise means more signal-to-noise ratio. Higher signal-to-noise ratios mean cleaner looking images.

The resulting image was adjusted for color, contrast, and brightness to bring out the stars a bit without washing out the background into a milky soup. What you see as a result is what your eye could see if you could watch the skies for five minutes use the best 3 minutes of what you saw. Just watch out – if you don’t move your head, the skies will move above you, causing the stars to streak a bit.

This was done without a Time Machine, by just putting the DLSR onto a photographic tripod with a 50mm lens on it. Because of the focal length conversion factor (1.6) of using a normal lens on a DSLR, this means the 50mm lens was turned into an 80mm lens, which is a little more telephoto than I would have liked, but it’s still nice. 10 second images were taken with computer software without tracking the stars, which means that there is just the beginning of a little bit of “star trails” from lack of camera movement.

So until I fine tune my new DSLR and software, just sit back, look up, and enjoy the face of Aquila.