M57 - no smoke without fire (Tom Gray)

M57 - no smoke without fire

I wanted to try imaging M57 at scale, given its relative brightness and position at the zenith. Using eyepiece projection with a 26mm plossl eyepiece, this was far better than I hoped for. I also managed to get my TEC cooler up and running again, reducing the camera temperature to 10 degrees below ambient (20 Celsius at 00:30!)

Imaging at a focal length of 5,500mm is difficult, even just centering the object is a challenge. Focus was pretty good, using a bahtinov mask and Vega , to provide sufficient illumination through my dual narrow band filter. Focus remained good, but dew formed on my corrector plate after just 5 x 300s exposures, bringing this imaging run to a halt. Whist Envisage maintained image tracking, and PHD showed RMS of 0.80", there was some drift due to less than good polar alignment.

Once the dew had been dealt with, I tried again, this time with 120s exposures to compensate for the tracking, and completed an hour of exposures, before the sky started to brighten. Ambient temp fell to a balmy 16 Celsius, and the TEC cooler to 6 degrees by 02:00. I had not changed the image capture to all uncombined fits images, and was fortunate that my LRGB one shot stack survived aerial interference. With four consecutive clear nights in UK, it is time to write an SOP and checklist to help my addled brain.

Original
Final
B
C

B

Description: This image comprises 30 x 120s exposures to try and compensate tracking errors. Definitely noisier than 300s image, but I think a little more detail is visible in the ring. The image was heavily deconvoluted with moderate sharpening, saturation and noise reduction. A final median sharpening and contrast enhancement using the life module in Startools, followed by post processing markup in iOS to remove unsightly banding and noise. I would be interested in which you think is the better image?

Uploaded: ...

C

Description: I thought I better post the original image (after processing in Startools) before I applied cosmetic darkening. I am still trying to determine if the unsightly band at the top (bottom of my Sony ICX429 chip) is due to a damaged array, and how well this will respond to cooling.

Uploaded: ...

Schmidt-Cassegrain Telescope (SCT) Imagers
Altair Astro 183 M/C Hypercams
UK Astro-Imaging
Optolong L-eNhance filter
The OSC Club (One Shot Camera)

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Status	Basic failed
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Astrometry.net job	3630611
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