M1 Crab Nebula taken with SPC900NC

Posted by XTSee on 15th October , 2011

The Crab Nebula (M1/NGC1952) is found in the constellation Taurus. It is a supernova remnant and pulsar wind nebula observed by John Bevis in 1731 which corresponds to a bright supernova recorded by Chinese and Arab astronomers in 1054. The Crab is located at a distance of about 6,500 light-years from Earth, and the nebula has a diameter of 11 light-years and expands roughly at 1,500 kilometers per second.

At the center of the nebula lies the Crab Pulsar, a neutron star just 28–30 km across, which emits pulses of radiation from gamma rays to radio waves with a spin rate of 30.2 times per second. The nebula was the first astronomical object identified with a historical supernova explosion.

M1 Crab Nebula

M1 Crab Nebula

This is my first attempt at imaging the Crab Nebula, and although I am pleased with it, I think it is perhaps a little overcooked in terms of the enhancing I have done with Photoshop. I think this is because I didn’t stack enough images, nor did I use long enough exposures. I captured 12 x 120 second images using WxAstrocapture, but due to periodic errors on the worm gear that drives my EQ mount, 4 of these had shifted/elongated stars making them useless for including in the stacking. I had polar aligned as accurately as possible (but not drift aligned, and have not yet got the necessary kit for auto-guiding), so 2 minutes was about the maximum exposure I could run, as beyond this the image was starting to produce oval shaped stars.

What this meant was that the data in the image was very weak, and so using Nebulosity and Photoshop to draw out the detail and colour resulted in a slightly false or cartoony look (certainly when compared to other peoples images of M1). No matter, I think its not too bad for a first go and using a cheap webcam.

150mm C6-SGT with f/3.3 Meade Focal Reducer, SPC900NC/LX (640×480) and WxAstrocapture, unguided
8×120s light+dark frames, Nebulosity, Photoshop (Starspikes Pro plugin)

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