M27 - The Dumbbell Nebula


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.