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First attempts at M51 by Gina

Gina

By Gina
in Imaging - Deep Sky

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Gina

Gina

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Very first attempt ;) I've got other collections of subs to try in DSS which I'll do shortly but here's something vaguely resembling M51...

No darks applied, no flats, no guiding, no nothing :) Just a collection of 30odd subs at 60s exposure and ISO 3200, stacked in DSS with histogram correction, saved as 16bit TIFF, loaded into GIMP and converted to 8bit in the process and further stretched and then cropped. This is 1:1 pic pixels to camera pixels.

post-25795-133877756502_thumb.jpg

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Quatermass

Quatermass

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Looks like you got your target ok there Gina shame the moon is out now though washing it out for a next go. The hard part for me was finding it to start off with then getting a dark enough sky and lastly correctly focusing it all up. Is this with your modded camera? I am finding my modded camera gives me an increase in noise levels now in the red channel which I'm having to deal with when processing. Great start should be easier to find now as well for you. I took sixty one minute subs for mine at an ISO of 1600 found that worked quite well and they were all unguided, an hours worth of unguided short subs seems to work pretty well for me at the moment but I will do guided ones later on still practicing the dark art of guiding.

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eddy

eddy

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If that were my first go id be more than happy :) Good job Gina, i found M51 quite hard to find as well, but with a bit of 'sweeping of the RA' i managed eventually, seems you had this framed pretty well ;)

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Gina

Gina

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Looks like you got your target ok there Gina shame the moon is out now though washing it out for a next go.
Yes found it :) I had a couple of hours fiddling about and taking sets of subs at various ISOs and exposures to see what will be best next time.
The hard part for me was finding it to start off with then getting a dark enough sky and lastly correctly focusing it all up.
Same here!
Is this with your modded camera?
No, this is with the unmodded one. Once I get sets of darks to match my sets of lights I shall probably swap image sensor assemblies and use the filterless and cooled one in the working body.
I am finding my modded camera gives me an increase in noise levels now in the red channel which I'm having to deal with when processing.
Really? I see! Looks like some cooling would be good ;) That's of course if I haven't damaged anything on the modded sensor assembly ;)
Great start should be easier to find now as well for you. I took sixty one minute subs for mine at an ISO of 1600 found that worked quite well and they were all unguided, an hours worth of unguided short subs seems to work pretty well for me at the moment but I will do guided ones later on still practicing the dark art of guiding.
Yes, I think that's probably the best way :p
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Gina

Gina

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If that were my first go id be more than happy :) Good job Gina, i found M51 quite hard to find as well, but with a bit of 'sweeping of the RA' i managed eventually, seems you had this framed pretty well ;)
Thank you ;)

Mars wasn't far away when I started trying to find it so I slewed to Mars and then centred it in my finder. Then when I slewed to M51 and took a long exposure, it was in the frame (just) :p

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Gina

Gina

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And yet another... This set is 12 of 15 stacked. ISO 6400 and 3 minutes per sub. Looks quite good in the TIFF file but I'm having no success at transferring it to my desktop ;)

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Gina

Gina

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Here it is - edited in GIMP in XP and then transferred ;) Definately needs darks subtracted from image ;) But at max ISO and long exposure it ain't too bad :)

post-25795-133877756562_thumb.jpg

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Gina

Gina

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I agree with Malcolm, the 3200 ISO is introducing far too much noise. Your PA also looks a tad off but other than that a great 1st attempt Gina.
My tests so far seem to show that 1600 is about optimum ISO for the 1100D (compared with 800 for the 1000D). Yes, my PA is a bit off still but better than it was. I've been intending to do a drift align but been concentrating on getting some M51 subs in the bag.
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Viv

Viv

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Gina - it's all trial & error & wo hoo's

good first one.

get guiding working & even if you're pa isn't perfect, you'll be fine.

Am very envious of your obvious dark skys .........

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Gina

Gina

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Gina - it's all trial & error & wo hoo's

good first one.

get guiding working & even if you're pa isn't perfect, you'll be fine.

Am very envious of your obvious dark skys .........

Thank you Scarlet ;)
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Gina

Gina

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Looking better and better Gina ;)
Thank you :) I'm learning that, although there seems little there, it's better with lower ISO. Next set is 3m at 3200 and is definitely better than 6400. Again 12 selected by DSS from 15 subs in the set.
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Viv

Viv

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Meant to say - i've found, when getting to process, there is a huge different in ISO

Although you may not see in a single, when stacked, etc - it really comes out.

I won't go over ISO800 on the 7D. I'd rather increase the subs needed. Even with an evening (35 odd @ 240 seconds), due to my lights (or excess of), it's just got no detail to it.

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Gina

Gina

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Next chance I get, I going for ISO 1600 and 2 or 3 minute subs and lots of them. May be able to get guiding set up too. I'm using the finder scope for both finding and guiding by the look of it. ATM the eyepiece is on it for finding but I can unscrew that and replace it with the QHY5 for guiding. I may decide to go for a separate guide scope such as an ST80. OTOH if I can do some calibrating of my pointing I may find I can do without the finder function. The only way I can find faint fuzzies ATM is the find a nearby planet or very bright star and centre it in the finder reticule.

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Gina

Gina

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Couldn't recommend the ST80 enough. It's the one everyone says use & I can understand why ........
Yes, I've seen all the glowing reports ;) Great price too particularly if I can arrange mounting it myself without having to buy expensive extras.
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Gina

Gina

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Great stuff Gina! What happened between the first one and the second one? All of a sudden it's not trailing!
Not sure now but it might have been when I did a bit of a polar alignment.
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Gina

Gina

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Now I need to go through the EXIF data saved with the subs and set up some dark subs runs. I have a number of darks already that I did a week or so ago there may be some of use from those.

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