NGC 7635, the Bubble Nebula
by Vern on Sep.06, 2006, under Astronomy, Deep sky, Planetary Nebula
NGC 7635, the Bubble Nebula, in the constellation Cassiopeia is a bubble of gas that has been pushed outward from star BD+60 2522 (the bright star towards the north, ie top, of the bubble). The gas is ionized by the starlight and gives off a glow which may be seen in a large scope, though it is quite faint.
Celestron Nexstar11, Meade F3.3 focal reducer, and Astrovid Stellacam II was used to take the image from Louisville, CO on Sept 5, 2006 around 04:38 UT. Temperature was 57°F, 72% humidity, sky was clear, transparency was very good, and turbulence about 6/10, bright moonlight. Stellacam II set at 9/14 gain, integrate 128 frames (4 sec exposure), medium gamma. The 15 minutes of video was dark subtracted and aligned with Registrax3, enhanced with ImagePlus, and cropped with Photoshop Elements2.
September 6th, 2006 on 5:52 pm
WOOHOO! Great shot!!.If I get some clear skies…maybe Friday night I will give it another try.The moon is going to be a factor though,grrr!.
One of these days I will learn to stack DSLR images in Registax if it can be done??.
September 6th, 2006 on 6:22 pm
Registax seems to have a limit on the size of files it can handle. Don’t use TIF! Instead, convert the images to BMP format. I’ve been able to stack 70 or so 3072×2048 images that way. You can subtract darks and correct flat fields with Registax as well. I’ve had mixed results doing so, however. Unfortunately, Registax doesn’t allow you to the scale flats or darks which is often necessary to get good results.