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M57 - the accidental image

antimorris

By antimorris
in Imaging - Deep Sky

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NickK

NickK

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;)

There's not much I can say that hasn't already been said - that's some accidental image!

Looking at the stars in the top left, I notice there's a slightly off centre defraction pattern. Just wondering if the scope is a little out of alignment?

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antimorris

antimorris

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Olly - you definitely should. This was the first time I had imaged through the CPC in a while (I normally image off of the EON I have piggybacked, see My Scope Setup but just got this Celestron Radial Guider and first night out was doing 30-45min subs reliably. The CPC is definitely a good imaging scope (well, in my opinion) and I havent dont the periodic error adjustment yet either.

NickK - I think that is more caused by my attempt to "pinch" and correct a few of the stars around the edges as I didn't have the correct spacing from adding the OAG so was getting some coma. I just went back on the original subs and that diffraction wasn't there, just an oblong star (oops!) ... I didn't notice that I spread out that one when I was working on it. I don't see that mistake on ay others, just some jpg artifacts and stretching artifacts so I am pretty sure that is what happened there ;)

I had to do some tricks I don't normally as my darks didn't match (time for an updated dark library) and I didn't get to take flats since it started raining on me so basically this image has no calibration frames (GASP!)

With that said, it might indeed be a little out of alignment from the move over here to the UK. I did a quick collimation adjustment when I first got it off of the moving truck, but it was via a homemade artificial star and not a real star so I should probably redo it under the stars one night soon.

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Tim

Tim

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That's nice Anna, be well worth spending time gathering some more data to get the noise down a bit. M57 was one of the first DSO's I ever took a photo of, and it has become something of a ritual for me to image it a little bit more each year and add the data in. Currently I have around 10 hours of Ha subs of an hour each to add in, haven't stacked them yet so dont know how much tertiary halo is there, but the secondary ring looks good, if it comes out half as nicely as yours I will be pleased :eek: You must have some nice skies?

Cheers

Tim

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antimorris

antimorris

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Yeah I plan on getting a bit more on a night with no clouds crossing my subs midway through so I can bring down the star size as well. If these clouds clear up next weekend like they are forecasted then I might be in luck to get a few more hours of Ha.

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MikeD

MikeD

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Hi Anna,

After having a go at this myself your result is for me even more impressive.:eek:

Below is a single 30 minute sub (screen stretched in maxim DL) with my my 10" 1200mm F4.8 newt and the outer shell is only just showing (the conditions were defiantly not the best).

Any chance you could post a single raw sub from your image to help me gauge when I have enough signal to go ahead and do a run be it 30 minute or 1 hour subs.

I would hate to waste clear skies on long sub runs if the signal will still not yield the outer rings.

Thanks Mike.

post-13376-133877605794_thumb.jpg

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antimorris

antimorris

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Mike -

If you read my message before I am replacing it - I was able to access my files via remote to pull a single sub. I am manually stretching it in PS as I don't have Maxim on this laptop ...

This is a non-calibrated sub (I only pulled one sub over and not the darks, etc) .... I cropped it down to show just M57

I didn't bother with layers to avoid blowing the center as I am pretty sure you just wanted to see how much outer halo was on a single sub. I also grabbed a sub that had a satellite through it as you can see in the lower right. The first halo has a decent amount of data on one sub here and you can just start to make out the second outer halo

edit #2: changed to a jpg

post-24627-133877605825_thumb.jpg

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MikeD

MikeD

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Thank's Anna, that helps alot.:eek:

Looks like I am just going to have to wait for a night of very good transparency, the contrast between the halo and background in you're sub is much stronger than mine.

Mike.

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