M1- Astronomy and astrophotography CCD camera images

Object name: M1 Crab Nebula
Popular name: Crab Nebula
Object type: SN remnant
Constellation: Taurus

An experiment. The moon was very bright tonight, and about 30 degrees from M1. I tried a few other DSO, but the sensitive SC3 camera was washed out by the light. So I decided to use my "nebula filter" which passes only OIII and Hb and is really designed for visual work. I was able to capture 106 frames at 30s, and had to discard half a dozen or so due to poor tracking. At 30s, tracking gets more tricky at this focal length. Focusing with the filter on was also tricky - but managed an acceptable focus. Compared with my LRGB M1 it does not show any more faint nebula, but does prove that useful imaging is possible in poor conditions. Overall, the image did not come out quite as well as intended, and the starshapes are dreadful despite a good guidestar. Must work on tracking! However, the result is encouraging. Not sure if I should have left the IR filter on - don't know if it would have made any difference.

An interesting page in M1 in different emission lines can be found here. Note that I did not get the same attenuation of the synchrotron emission from the Crab's pulsar that is shown in Richards image. Guess I need a better filter.

This is the first time I've tried this filter since my Pease 1 experiment last September.

Stacked in Registax 3 with dark and sigma clipping to remove hot/cold pixels. Exported as tiff to photoshop and curves applied. Also exported to IRIS as fits and one itteration of RL deconvolution applied. Exported back into Photoshop as raw. A layer containing the nebula and bright stars from the deconvoluted image was layered over the curves image. Image flattened and then minimum filter applied to bright stars to desaturate. Black point adjusted slightly in levels and image cropped.

Exposure Details :

IR Block OIII 100x30s on 200mm @ F5 with SC3.5

Curdridge Observatory, Southampton,UK