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My latest effort taken over two nights, Christmas Eve and New Years Day.

Took 70x25s (24/12/2020) and 70x10s (01/01/2021) exposures with a Canon 600D (plus 20 darks and 20 bias for each stack, ISO800) in an effort not to blow out the core by stacking and merging the different exposures in Photoshop. Safe to say, I failed in that respect. With a focal length of 1500mm, getting most of the main nebula structure in frame was always going to be near impossible. Still, a significant improvement on my first shot of this target two years ago which is somewhere on this forum perhaps. I'm not sure what the object to the centre left either. Hopefully, another opportunity to get longer exposures will come by, I think I can push it to 40s before trailing becomes an issue. Still, trying to fathom accurate polar alignment on the EQ5.

Stacked in DeepSkyStacker, 3x drizzle applied. Further processing in Photoshop, levels, curves, saturation, setting black and white points plus noise reduction.


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10 hours ago, rob_r said:

Stacked in DeepSkyStacker, 3x drizzle applied.

This is a good start for a difficult target - certainly better than my first attempt that's for sure.

I'm not sure about using drizzle unless you have used dithering and I assume you haven't as you are not guiding.

I know this article is primarily centered on AstroPixelProcessor but it is worth a read regarding when to and how to use drizzle. I am a bit concerned that by using drizzle you may well have increased noise.



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Thanks for the pointers, @Adreneline. I think I left 3x drizzle checked by mistake which initially led to me wondering why my Mac was running low on RAM. I'm still finding my way around DSS. Siril was giving me some weird patterns in the final stacks I tried that. In any case, I still have the RAWs so I reprocessed it last night and this led to a much cleaner image and did a little better with the core. I'm not guiding yet and it is something I'm working towards but I want to get the tracking pinned down first as the mount should be capable of stable exposures longer than half a minute. Thanks for the article, it made a lot of sense.


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3 hours ago, rob_r said:

a much cleaner image and did a little better with the core

A definite improvement I would say.

I'm afraid I cannot help with the EQ5 as I am not that familiar with that mount.

I used to own a NEQ6-Pro (similar I guess) and I used an iPhone app 'Polar Scope Align Pro'. I needed to rotate the RA axis to ensure the reticule in the polarscope was aligned as per the app but it certainly much improved my PA. I also experimented with SharpCap with some success but I now use a PoleMaster with my CEM25-EC and the resulting PA is very good indeed.

Good luck!


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