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NGC891 @2800mm FL


cfpendock

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Sunday was the first possible night for imaging for a very long time, even though it was rather windy which is not good for a CPC 1100.  But I got 16 x 5 minutes each of LRG and 12 x 5 minutes of Blue.

I found controlling the stars was (as usual) very difficult with the CPC1100.  In particular, stacking binned images can produce artefacts in both DSS and Astroart - perhaps I should have increased the image size for stacking and processing.

 

Atik 4000

Deforked CPC 1100 sitting on a Tak EM200 mount.

All limages binned 2x2.

Chris

 

5a0c1f28b5a71_ngc891.thumb.png.507fad3ccf9188efc4f0eef803135e9b.png

 

 

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9 minutes ago, Lockie said:

These long focal length shots are my favourite, but I do appreciate how tricky they are to capture, well done!

Yeah, very tricky.. very seeing and atmospheric stability dependent... night to night it can be worlds apart in quality with same setup, same object and same alignment....

 

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Great result, this is definitely what I want to do more of, for some reason this aspect of astrophotography appeals to me much more than wide field shots of emission nebulae.

Unfortunate really, given the demand it places on the optics and mount, plus the UK's generally mediocre sky quality, but I like what I like!

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2 minutes ago, knobby said:

Was this guided ? OAG ?

Oh yes.  I doubt it would be possible to image at this focal length for more than a minute or so without guiding.  Especially since my EM200 mount has a limit of 18kg, and with the big scope and other stuff it is already around 15kg.  And it is partly for this reason that I use an OAG - it is much lighter than using a separate scope, as well as eliminating any guiding problems due to flexure. 

Chris

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Good going, Chris. I've re-shot the luminance on my effort from a month or two back. The key thing at high resolution is the seeing. There's no way round it. In the Mk1 version the seeing was dire, with a FWHM of about twice what we see on a steady night. The new data from this week is incomparably better. I think this is far more important than the theoretical resolution of the system.

Olly

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1 hour ago, ollypenrice said:

Good going, Chris. I've re-shot the luminance on my effort from a month or two back. The key thing at high resolution is the seeing. There's no way round it. In the Mk1 version the seeing was dire, with a FWHM of about twice what we see on a steady night. The new data from this week is incomparably better. I think this is far more important than the theoretical resolution of the system.

 

Thanks, Olly.  I used your technique for layering in stars from the first stretches into the final image, otherwise they were completely blown out and colourless.

Chris

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1 hour ago, Davey-T said:

Nicely done, encouraged by your image I had a pop at it last night with the 10"SCT 2500 f/l, haven't looked at the result yet :)

Dave

Thanks, Dave.  Yes, last night was good so I had a go at NGC660.  Now that really is many removed words!

Chris

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34 minutes ago, geoflewis said:

I love it. It knocks the socks of my lame effort with the C14 a couple of weeks ago during full moon....

Thanks.  Faint targets at f10 need very dark skies which of course normally we don't have.....  But with a full moon? No, no!

Chris

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9 minutes ago, cfpendock said:

 Faint targets at f10 need very dark skies which of course normally we don't have.....  But with a full moon? No, no!

Yep, I'll have to shoot it again, but typically that was the first clear night in a few weeks and I'd always wanted to have a go at that target.... Here it is - very bland....:(

 

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9 minutes ago, geoflewis said:

Yep, I'll have to shoot it again, but typically that was the first clear night in a few weeks and I'd always wanted to have a go at that target.... Here it is - very bland

Sorry, I never saw your post.  

Well, for a full moon, I'd say that was pretty amazing.  I don't have that excuse, so I look forward to your next go!

Chris 

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