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Though M101 is a relatively large target it is quite dim and this required a significant effort to get detail into its core. I took 31hrs of 30sec exposures which I then thinned down to the best 18hrs of data. Processed in APP and PS it was tricky keeping the core detail that I had imaged from blowing out.
Lots of advice and lots of very small curves stretches was the key in the end. Hardly sharpened it much with noise reduction undertaken as and when noise just stared to appear during stretching.
As the sensor is biased towards red, colour balancing with green and more so with blue was also necessary.
Taken at Gain 200 with a UV IR cut ASI224MC uncooled camera, APM107/700 scope on an AZEQ6.
It’s a good little sensor if you have the conditions (cold nights) and use Flats, Flat Darks and take Darks every night as the sensor temperature varies being uncooled. For info, I found it ran at about 6 degs above ambient once it was steadily running subs off.
Hope you like it.
I tried imaging M101 here in our Bortle 5 neighborhood and it was sort of tough due to the light pollution but I think I was able to pull off a bit of data. My problem now is that I was able to increase the visibility of the galaxy through stretching but in the process the background noise also increased. I also noticed that my galaxy and stars are a bit orange/reddish compared to the other M101 shots which are kinda bluish in color. Not sure if this is being caused by my astromodded camera but I tried correcting it via Photoshop and this is the best "white balanced" image that I got.
Looking for some help in this group maybe someone can have a go with my raw file and share some techniques on how to improve my post processing. The stacking was done via DSS and the processing via Photoshop. I also used Gradient Xterminator and also Astrotools.
Here's my edit and I also attached the raw file so maybe you guys can try tinkering with it also. Also open for any suggestions or comments with my initial edit. Thanks! 😁
Light Frames: 189 x 1 min shots @ ISO1600 (yes I still don't have autoguiding) Dark Frames: 198 x 1 min shots Mount: Celestron OmniXLT CG-4 Telescope: Celestron C6N Camera: Canon EOS Rebel XT Hap-Griffin Mod Autosave.tif
I'm selling my brand new-never used QHYCFW2M-US filter wheel for 8x1.25" mounted filters.
It will be shipped in its original packaging (with extra packing of course) with all the components that came with it included (cables, adapters, screws, etc).
If you have any question/s please ask.
Price: 250£ + shipping-fees
Thanks for looking!
I scrapped all the Oiii and Sii data I previously took during a full moon (about 15 hours worth) and retook it all when the moon was a bit smaller at 76%. Ha was taken during 98% and 67% moon. All the lights were taken on the following nights: 12th, 19th and 20th September 2019.
Integration times, all in 600s subs unbinned:
Ha = 28.33 hours
Oiii= = 5.67 hours
Sii = 5.67 hours
The Ha data is really nice, and unsurprisingly the Oiii and Sii is not as strong (or nice).
I'm missing that (vital) step in my processing routine of getting the Sii and Oiii properly stretched to match the Ha, before combining. I dont really know how to deal with the weaker data properly. Any pointers would be appreciated.
What I do currently:
All the data is loaded into APP into separate channels/sessions.
The data is stacked and registered against the best Ha sub
This produces individual stacks of Ha, Sii and Oiii that are all registered
Each channel is processed with DPP in APP and then saved as a 16bit TIFF
Each is opened in PS
Stars removed with AA and any remnants removed and tidied up
I then open a blank RGB document in PS
I paste Ha into Green, Sii into Red and Oiii into Blue
Adjust the selective colour settings to get 'Hubble palette'
Adjust levels, curves, saturation until looks ok
All the Ha Sii Oiii data is then combined together in a single 'super' stack in APP using quality weighted algorithm to create a 'luminance'
That luminance layer is adjusted using levels, curves, and NC tools such as local contrast enhancement and deep space noise reduction (using masks to apply as required)
The luminance is pasted onto the above colour layer, and incrementally added using gaussian blur
Cropped and saved.
Here it is anyway I haven't intended on any more exposure time for this one, but will consider it, if the expert opinion dictates otherwise!