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Well that worked I think!


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M51 was playing out last night but the sky had a lot of clouds. I had the Skelescope set up but the open frame seemed to be a problem, so I swapped to the Skywatcher 200mm f/5 Newt. The contrast was still quite poor as the camera was reading the dark bits as 50% of the value of the white bits, no real black bits at all.

This is 20 frames at 7 minutes each, so just over two hours of data. The image is at about 100%, cropped to fit. Hope you like it.

image.jpg

Click for the bigger version.

Captain Chaos

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If i had a hat, i would take it off for you on that one CC, that my friend is the best image you have done , and a lot better than i have achieved on M51, dont think you can improve on that one except ,its crying out now for colour, which i,m sure you will get the next clear night, well done mate ,all that hard work is paying off .

Rog

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Another gem CC. Lovely detail. Another one for an RGB. The guiding is working a treat. All coming together now with some stunning images.

M51 is in quite a light polluted area of my sky and I found the other night that I could only go for 3 mins with a CLS filter before I had significant sky glow. I use maxim to capture and you can run the infomation cursor over a trial image to judge how much sky glow you have. Once the figure gets up to 3000 (on a 16 bit image) there really isn't much point in exposing individual subs for a longer period since the sky glow will be washing out the read noise anyway.

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I,m a bit like you Martin , not sky glow , but my 6 min exposures run into problems , when i get this super guiding system done ,i have the problem of aircraft, i,m on a flight path so have to avoid that part of the sky,do you have that prob CC, or are u lucky to avoid this ,

Rog :)

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Thanks folks, quite pleased is close, but doesn't quite cover it :)

Rog., you haven't tried M51 yet is all. Plus you don't have a Newt! :) Aircraft are usually rare, but can get fierce if Leeds-Bradford and Manchester have the wind in the wrong direction. It's not processable when they do mess it up as they usually leave daubs rather than a pattern of dots. They also seem to calm down after 11PM, maybe they don't fly after then?

Martin, I'm running at a background level of around 8500 on these subs, which is about double your value for double the exposure, so the sums seem to add up. I'm not sure if that means anything to me yet, but it does make sense. I was going for subs that didn't quite fill the histogram, so the brightest bits are still not up to the maximum that the camera can do. Read noise (and hot pixels) doesn't seem to happen with the 16HR, maybe that's something to do with the USB1 interface being less demanding. I need to get some RGB on this one as well as some Ha on this and the last one so I need to book some clear sky. Clearer than last night would be great!

The digital development left some dark halos around the stars, so I think I need to tweak the processing there as something isn't quite right, but it seems to be getting close.

I've been thinking about buying Lucy Richardson some flowers as well, as she seems to have fallen out with me. :D

Captain Chaos

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The 16HR is like the sxvh9 with very low dark current noise but there is read noise. If there weren't we could just do loads of 30 sec exposures and not worry about guiding! Your image speaks for itself CC so who am I to comment!!!! :)

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bloomin' crikey - that's sheer beauty! Fantastic stuff there CC - I'm envious to say the least.

Thanks folks, quite pleased is close, but doesn't quite cover it :)

Rog., you haven't tried M51 yet is all. Plus you don't have a Newt! :D Aircraft are usually rare, but can get fierce if Leeds-Bradford and Manchester have the wind in the wrong direction. It's not processable when they do mess it up as they usually leave daubs rather than a pattern of dots. They also seem to calm down after 11PM, maybe they don't fly after then?

I'm on a flight path, they come from the east and ruin my night vision with their glaring headlights! I was having a nice peek at the beautiful swirling clouds of M42, when there was a bright light from my left - look at it "*$@**£ planes", look back - nothing :)

Yeah, planes aren't allowed to fly after a certain time. (They should be in bed and will get told off by mummy plane).

Still can't get over that image! :shock:

Andrew

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