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View Full Version here: : Southern Pinwheel Galaxy (Help)


AstroBogan
08-04-2018, 06:42 PM
So i decided to try again with another galaxy and managed to snap 40~ lights 45 sec subs @ 800 ISO, 15 darks and 20 flats.

Taken with a SW ED80, HEQ5 unguided and unmodded cannon EOS 60D in my light polluted backyard.

I'm not sure if it is due to light pollution or my camera in general, but no matter what I do with my processing, I cannot get the image to look clear. (see raw stacked image and then the cropped processed image).

Any advice?

raymo
08-04-2018, 09:56 PM
Jacob, I wouldn't bother with flats at this stage, you won't see any
difference in the end result.
The background is quite a lot too light, which washes out the galaxy.
If you darken it, it will make the galaxy pop, and beneficially, will hide
some of the noise. More subs will help to reduce the noise also.
Your image is lacking colour; this galaxy should be distinctly blue.
An LP filter might help if you are badly affected where you are. You
will probably just have to attend to the colour cast it introduces.
I have attached an image showing how 83 should look using shortish
subs like yours,[but using JPEGS]. My background is actually a smidge too dark.
raymo

AstroBogan
08-04-2018, 10:04 PM
Thanks for the info Raymo, any advice on which LP filter to go with? I have no experience with any of that. But yes, I am unfortunately dealing with a lot of light pollution (30 mins from Sydney CBD) which has a terrible glow in every direction it seems like. i'll try for more subs next time, and hopefully my processing gets better!

raymo
08-04-2018, 10:35 PM
I don't have much experience of LP filters, having lived mostly in small towns. You'll have to see if someone else offers help.
raymo

sil
10-04-2018, 11:29 AM
I'm a nikon guy myself but i know there are a bunch of inbody-drop in filters available for canon. I think there are ones suitable for modified or unmodified cameras, so read up on the details. Remember a filter blocks some light so expect to need to increase exposure time and/or stretch further in processing, but with a filter you are gathering more usable signal and dont need to remove as much colour cast later on in processing. Highly worthwhile getting one. If you have a choice of brands I'd be inclined to research but likely go with the expensive option, not just the cheapest i find on ebay. A poor quality (cheap) filter may be removing more than just light pollution and/or introducing chromatic problems. With optics the extra cost for quality is worthwhile.