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M81/82 - LRGB

Whippy

By Whippy
in Imaging - Deep Sky

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Whippy

Whippy

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Another clear night :(. 2 clear moonless ngihts in one week? Something's not right.... Anyway, I managed to get the RGB data for the M81/82 mono image I took on the 2nd of January (see here: ) Have to say that with the amount of time I've given this, I'd have thought it might be a bit more colourful but I've pushed the saturation as far as I'm comfortable with and this is the result. c'est la vie as they say, I'm still quite chuffed with it nonetheless.

So, M81/82. Total exposure time 5hrs 58 mins (Luminence: 3hrs 6 mins (31x6 mins), Red & Green 52 mins each (13x4 mins and Blue 1hr 4 mins (16x4) colour binned 2x2). Taken by an Atik 16HR with Baader RGB and IR cut filters and a Hutech IDAS LP filter through a WO ZS66. Guided by a WO ZS110, QHY5 and PHD, all riding atop an EQ6 pro. Stacked in DSS and processed in Photoshop.

11993_normal.jpeg

(click to enlarge)

Tony..

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Tim

Tim

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Nice Tony. You aren't the only one struggling with colour for this target! Actually, this is, in fact, exactly the image I will be looking for for my next registar attempt. I have not been able to stop thinking about that image of M81+M82 you posted that was surrounded by the integrated flux. I am determined to get at least something of that flux on chip, no matter how long it takes :(

So far I have around 10 hours, but none of it has been during decent seeing. There is a lot of red noise showing up around the galaxies though, and if I saturate the red, jack up the brightness, desaturate, then blur like hell, there is a pattern to the noise, and it matches the pattern in the pic you linked to. So it's there, its just getting hold of it!! I have a problem with what appears to be a ring like a coffee mug ring in just the red channel too, dont know whats causing it, but when the image is stretched as much as it needs to be to get the flux out, it really shows up, any ideas as to cause, in just the red channel, gratefully recieved.

Nice going Tony, whats next?

Tim

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glennbech

glennbech

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Great pic! Im still sureprised, amazed (and a bit envious) of how "up close and personal" you get with short focal length refractors and CCD cams with "small" chip sizes (compared to DSLR)...

I especially like the detail in M81. There seems to be a hint of noise in the blue channel. Is that a result of stretching the data, or jpeg compression?

Maybe you could combine the current result with a DSLR colour shot? My modified 10D picked up heaps of detail in M82 during a very short session 18. October last year. You can see the image (just 12x40 seconds) here; http://ukastronomers.com/glennbech/image/9526_large.jpeg

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Whippy

Whippy

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Indeed Tim, I did think that 6 hours at f5.9 would give me a little more colour (especially the Red in M82) than what I've got but you look at other people's work, maybe not but it does go to show just how good that one with the integrated flux is. You're more than welcome to use my data in your registar attempt Tim, let me know and I'll zip it up and post it up on UK Astronomers. Not sure what's causing your Red channel issue though, there was a thread on here recently about some DSLR's having more noise in the Red than the Green and Blue, might be that?

What next? I don't know! Maybe a few more hours on this image as it's going to be a few weeks before it 'goes South' (maybe some Ha?) but I've got all the necessary adapters to use a 6.3 reducer on my ZS110 (it'll bring the focal ratio to about f4.5ish :( ) so I might have a play with that.

Thanks Glen :), your pic has that Red that seems to be non-existant in mine and you've only done 8 minutes! I think it's because the chip on my camera has small(ish) pixels that enables me to use scopes like the 66 and yet gives half decent resolution. Saying that though, I have been reliably informed that given good seeing conditions, my camera's 'sweet spot' in terms of focal length is about 1200mm which would give me a FOV of about 18x25 arcmins, that's a bit smaller than the 60x80 arcmins I get with the ZS66! You're right about the noise though, I normally don't push the processing so hard but after two 3 hours sessions, I really wanted to see a bit of colour!

Tony..

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vincentnm

vincentnm

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Great image, you seem to have excellent data in there. . Sorry, I could not resist, I had a play with it. Ran Noel's Actions

1. Light Pollution Removal

2. Colour Blotch Removal

Struggled a bit to avoid clipping the black while applying LPR.

Thanks,

Vincent.

12032_large.jpeg

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Tim

Tim

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Tony, Im using a qhy8 now, but even a 400 sec sub shows up a fair bit of red in m82, even without stretching. If you could send all your stacked files, but unprocessed, that would be great. How does the L channel only look?

Im starting to think the skies round here will NEVER offer a chance at getting some of that flux on the image. Im gonna give it 20 hours though I think. At least its an easy target and can go for hours and hours without worrying about meridian flips!

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Whippy

Whippy

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No worries Vincent, I've got no problems with people having a play with my images :(.

Tim, the luminence is here: http://stargazerslounge.com/index.php/topic,36862.0.html . But I'll zip up the L, R, G and B stacks up and upload them onto UKAstronomers so you (or indeed anyone :) ) can have a look if it'll help.

Thanks Rob & Ron, here's the image me and Tim are talking about: http://blog.deepskycolors.com/archive/2009/01/03/m81-M82-and-Integrated-Flux-Nebula.html . Quite the showstopper eh?

Tony..

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Beyond_Vision

Beyond_Vision

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Is the saturation level option for mono as well as RGB images Kevin? I can't seem to find it...

And here's the link for those unprocessed stacks: http://ukastronomers.com/user/add_files#whiplash/action/files/show/115/ajax/true . Enjoy :(.

Tony..

Woops forgot that you were doing RGB. On a colour stack the image in DSS it is always washed out and needs a tweak with the saturation slider.

Regards

Kevin

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Tim

Tim

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The flux image also shows how tough it is to get the Ha burst on m82.

Looking at the flux image, the background stuff has been heavily blurred and sharpened. Maybe i'll try that. The only way it seems to show up at all is in the red channel as patchy noise. By heavily saturating that channel, blurring it like mad, then upping the contrast and stripping the colour, you can maybe just about make out a few of the darker areas among the flux. But its tedious.

DSS is just stacking 128 images for me, after that i'll take a look at yours Tony.

EDIT: Yep, just looked again at the flux image, if you notice the stars, esp the brighter ones, they have a misty halo. I think this is caused by heavily blurring the whole image, and then using that layer. It'd be nice to think that it was the stars shining though the flux, but im not sure, anybody got any thoughts on that? ta.

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MartinB

MartinB

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Great work Tony. The star and core colour looks great. The outer arms of M81 are a tad green here.

That flux looks horrible, I spend ours processing out that sort of junk :( How come we wait ages for clear nights and then people try and capture cloud! Seriously, it's a spectacular image, very skilled, and very interesting that the Milky Way can give that sort of a glow.

From now on I'm going to attribute all the mush in my pics to that sort of thing. So lots of comments along the lines of "dead chuffed to see Vincent's bands appearing in the top left corner along with the even more elusive Burdett's ionisation rings". All my imaging problems sorted.

BTW, I reckon you need to use Ha to get that outer starburst stuff.

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