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M51 (Whirlpool Galaxy) - 04/03/2014


xanthic
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Here's my first attempt at M51. Not the best conditions as I'm peering through the Notts light dome (the first few subs I collected have poor contrast and were not usd). It took me a while how to work out how to lower the noise. I wish I'd had more subs. May try for more later.


 


 


12 x 600 secs, stacked in DSS, processed in PaintShop.


 


m51final.jpg


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well done Leigh, one of my fav targets, very difficult to get right i find and get some colour out of it,


i had a go at this the other night myself, managed 14 x 5 minute subs with darks but still struggling with the processing myself so haven`t posted it yet.


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Blimey, that is an impressive image! The background stars all look round and I can't see any of that nasty coma; I think you've nailed it in my non-DSO-understanding eye :)


 


It's great that you are able to get such good results with a 150mm Newtonian - I've no idea what I mean by that, but I've not seen other people generating these sorts of images with that scope. You've picked up guiding like a duck to water, but then you are a geek!


 


Looking at M51 on Stellarium to see if you'd had to crop the image much (it looks like your final image has a FoV of about 0.9 degrees), the Stellarium image of M51 shows there is a load more whispy stuff around the smaller galaxy; have you had to process this out to get a pleasing image, or as you've suggested do you just need more data?


 


But it's a super looking image. Must be very rewarding, and I'm really pleased for you. 


 


JD

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Thanks for the encouraging comments :)


 


James - yes, I think I need more data to tease out more detail. I'd be interested to know how much better the image would look if I could double or triple the number of subs. I suspect I should perservere and get some more, rather than trying to get more objects collected...


 


Graham - this was with my Canon 7D.


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Well only one way to know how much difference more data will make .... :)

Sort out the secondary dew heater, and then just leave it running all night!

Do DSO imagers need to adjust focus much during the night? With planetary using an SCT/mak it seems to need adjusting every 30 mins or so in my experience, and that is backed up by what Peachy says.

Jd

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Well only one way to know how much difference more data will make .... :)

Sort out the secondary dew heater, and then just leave it running all night!

Do DSO imagers need to adjust focus much during the night? With planetary using an SCT/mak it seems to need adjusting every 30 mins or so in my experience, and that is backed up by what Peachy says.

Jd

 

yup the focus changes as the DSO get higher or lower in the sky due to the amount of atmosphere you have to image through.

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I'd used the TIFF from the first processing. I'd removed as much noise as I could (though it had started to clip on the black end a bit). The second image, I just pushed the saturation up. There is still a small amount of vignetting, even though I'm using flats. I'm guessing I ought to flock the tube.


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It's probably not the "thing to do", but I've just put the two images side by side (below). The back ground sky on the right (re-processed one) is darker which is more appealing, but I feel it looks "over" processed; I feel the left hand one (the original) looks more natural, though I appreciate there is more detail to be obtained. Of course this is only my opinion, and as I've said above I don't know much about DSOs or the procesing side of things.


 


M51_leigh-gingered_zps6cc558da.jpg


 


JD

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