M27 - The Dumbbell Nebula |
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The remains of a star that reached its end of life. When a sunlike star runs out of fuel, it balloons up and throws off its atmosphere. The core shrinks to a white dwarf. Also known as NGC 6853, this irregular planetary nebula is found in constellation Vulpecula (The Little Fox with the Goose). It has a magnitude of 8.1, and size of 15.2 arc-minutes. It is 1,250 light years away.
This shot is a composite of five 10 minute luminance, one 10 minute red, one 10 minute green, and two 10 minute blue frames. All frames were unbinned at f/10 with the 12" LX200 and ST-8E.
The AO7 adaptive optics unit was used to rapid guide on a magnitude 10.3 star just north of the field. Some frames were at 0.1 sec, some at 0.2 sec, and some at 2 sec. (I was experimenting.)
Processing included "by the numbers" color calibration (1.15 : 1.00 : 2.05 native ratios at 68° elevation gives 1.15 : 1.01 : 2.07).
Taken on July 28, 2000 at my home in Monmouth.
This previous shot, taken a year earlier, was from the first run in which I attempted color:
Built from 4 minute exposures for each
of red green and blue. Taken at f/6.3 with the 12" LX200 and
416XT through the Meade 616 filter wheel. Autoguided with a 201XT through
a 90mm ETX.
Color balance was achieved by examining a G2 star. However, the blue frame has a low signal to noise ratio by about 3X over the other frames since my CCD is less sensitive to blue. I should have used a longer exposure for blue. When the blue frame was scaled up to set the color balance the noise was scaled up also. This seems to give the sky background a blue cast.
Taken at ARGO on July 10, 1999.
The image below was taken Aug 28 1997 at the Oregon Star Party
A 1 minute exposure taken with the 200 and Meade 416XT at f/3.3.