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M51 - The Snail Galaxy (LRGB)

PhotoGav

By PhotoGav
in Imaging - Deep Sky

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PhotoGav

PhotoGav

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I thoroughly enjoyed SGLX, but thoroughly failed to gather any decent subs. On the drive home I realised what I had done wrong with my polar alignment set-up and the reason why my guiding was so shockingly poor... Lesson learned! On arriving home, I successfully set everything back up in the garden and have really enjoyed a couple of good nights with the kit working 'perfectly'. The old slumber on the sofa with the occasional eye on iPad teamviewer, followed by a sharp awakening at 4am to shut everything down. Love it!

Anyway, I ramble on...

Here is the result of those couple of nights - M51, to me, more of a Snail than a Whirlpool, the target that I had intended to image from Lucksall, but had to chuck all the duff subs!

post-29321-0-50605000-1427579540_thumb.p

Celestron edgeHD 800 with QSI683

RGB = 6 x 600s each

L = 24 x 1200s

Total = 11 hours (a new personal best!)

I'm happy with this result, but the image is suffering from quite a bit of colour noise. My conclusion is that I need to shoot more RGB subs. My, this f10 imaging is a sloooooooooow business. Mmm, 'snail' seems quite appropriate really!

As ever, all thoughts, comments and criticisms most welcome.

Clear skies all.

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Gina

Gina

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Great image :)  Good processing for a relatively small amount of data at f10.  From my experience at f5 I think you could just about double your sub exposures without saturation.  You'll certainly need a lot of clear skies to collect enough photons to clear the background noise.  This is very much a great start :)

I can see why you call it a snail :)

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PhotoGav

PhotoGav

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Thank you all for your encouragement. Yes, f10 imaging isn't really ideal under English skies, but this is what I currently have available so I continue to bang my head against the wall! Keeps me occupied in Galaxy season...

Sent from my iPhone using Tapatalk

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swag72

swag72

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I think that a comparison would be really useful between 1x and 2x bin. Now I know that it would theoretically waste imaging time, but if you could put aside a few hours and take x number of 1xbin and then the same number of 2xbin and then stack and compare them by stretching exactly the same - You may find that one works better for you and then you will categorically know which will give you the best results.

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PhotoGav

PhotoGav

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Thank you all.

Yes, 2x2bin for the RGB could help to speed the collection of that. I will definitely give that a go with the next project.

As for 1x1 vs 2x2, Sara, I did that experiment on my first project with the edge and M27. My conclusion was that, for luminance & narrowband, 1x1 was better as there was no noticeable difference in quality, but 1x1 gives a bigger image - better for printing, which is my ultimate goal with these images.

Focal Reducer - I have a duff one that I am in the process of sorting out with the wonderfully helpful FLO. Watch this space!

Sent from my iPhone using Tapatalk

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Twisted Lip

Twisted Lip

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Looks cracking Gav, you should be really chuffed. Out of interest, what went wrong with the PA at SGLX (other than me putting you off with cider of course)?

I still haven't manage to process anything that we took on the last night but I'm not expecting anything overly world-beating!

Cheers

Will

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Davey-T

Davey-T

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Hi Gav, lovely snail, nice to meet you at SGLX, I didn't even get my guiding working but wasn't too fussed as I spent most of the time wandering around making a nuisance  of myself, plus a clear sky eclipse bonus.

I did M51 many moons ago at f/10 RGB binned 2x2 and it came out OK as I recall, lurking somewhere on a backup disc that I can't even find lol.

Dave

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PhotoGav

PhotoGav

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Thank you folks.

Sara - I will be with Edge for the foreseeable, but have designs on a larger, though smaller than the edge, refractor. Along with all the other items on the wish list... Consequently I am just sticking with the kit I have for now and aiming to get some hours under my belt. Then I will feel that I deserve any new toys!

Will, I should PM you really with the horrible truth. But in the interest of shared advancement I will swallow my pride... I used astrotortilla to centre both alignment stars in Alignmaster. That gave me perfect polar alignment stats, but not perfect polar alignment. Solution, uncheck 'sync scope' in astrotortilla when aligning the second star. Then you get the real PA stats and can go through the adjustment routines to improve PA. Did that when setting up back home and my guiding was lovely!

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