This is my most ambitious project so far, the data was collected over 3 nights.
M27 is typically imaged with a CCD camera and 20 or 30-minute long subs to capture the dim outer halo of the planetary nebula. So I was very pleased to see the outer halo after only 2 hours of exposure per channel while using very short, high-gain subs with the ASI1600MM-C.
M27 – The Dumbbell Nebula
8 July 2017:Â Ha filter: 16 x 120 sec (-15C, Gain 200)
13 July 2017:Â Ha filter: 53 x 120 sec (-15C, Gain 200)
15 July 2017: OIII filter: 55 x 120 sec (-15C, Gain 200)
Total exposure: 4.1 hours
The bright star on the right is magnitude 5.5 and causes a dim reflection, but I kinda like the aesthetics. In the future, I might try to get some RGB data too for the star color.
I’m really pleased with the amount of detail that’s visible at full resolution. The outer wings are very faint and difficult to observe with amateur equipment, especially from light-polluted areas. That’s where narrow band filters really prove their worth.
This planetary nebula is formed by shells of gas, expelled by a Red giant star near the end of the star’s life. The star then collapsed to form a white dwarf, visible as a small white dot in the core of the nebula (click the image for full size). The hot dwarf star emits strong ultraviolet radiation that ionizes the surrounding shells of gas, producing bright colors.
The core of M27 is very bright and can easily be observed as a bar-shaped object, hence the name ‘Dumbbell Nebula’. Photographically, the core often resembles an ‘Apple core’ due to the white center and red edges.
Finally, here’s a comparison with my image from last year, shot from the same location:
The image on the left was captured on 23 Aug 2016 with a Canon 450D and ST-80 telescope. Exposure: 61 x 30 sec (30 minutes)
UPDATE 09-08-2018:
Complete rework with a synthetic green channel, based on Marcel Drechsler’s bi-color style (https://youtu.be/5a-OuhdEskg)
Astro Virus 
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