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M95 & M96 mosaic; return after a long gap...


661-pete

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...nearly 8 months since my last time in France and my last imaging session, in fact (pressure of work - and money - wondered whether I was giving up the hobby as it happens ;)).

Ah well, found all the kit more or less still in working order and had a go at this pair. I really owe it to John (JGS001) for inspiring me to put these on the TO DO list, and I was planning to get them in one frame, but that would have meant orienting the camera the other way and I was wondering about the coma. So - hence the mosaic.

Anyway I've quite taken a fancy to these galaxies.

Which now begs the question: my first attempt at a mosaic, how do you exactly blend in the sky colour? I evidently haven't done it right, you can see the boundary between the two images. Haven't tried IMerge, will that do it for me?

I had no problems snapping the two frames into alignment (using layers, set one of them partly transparent, then move it about until the stars exactly register...) but I couldn't figure out how to equalise the backgrounds.

Imaging details: each pane 16x3minutes Europa250 + 350D at prime focus, 1600ISO.

Anyway, all comments, suggestions, 'tweaks', welcome...

post-14835-133877363939_thumb.jpg

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Nice image Pete...

The backgrounds would have been easier to match if you tackle the gradient in each image first I think thats whats giving you the problem once you have done that whilst you still have the layered version of the file adjust the brightness contrast levels etc until the two match and feather the edge...

Peter....

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The backgrounds would have been easier to match if you tackle the gradient in each image first I think thats whats giving you the problem once you have done that whilst you still have the layered version of the file adjust the brightness contrast levels etc until the two match and feather the edge...
You're right, Peter, the gradients are very obvious seen on my monitor at home - but not on my monitor at work! Didn't know I'd left so much gradient in - vignetting mostly. I'll have another go at this tomorrow perhaps, must get some kip now! Thanks.
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You need to get rid of the gradients first so each frame is as flat as you can get it. Are you using Photoshop? Rather than use Brightness/Contrast I tend to overlap them as you have done and then re-visit the brightness and contrast of one pane only using Levels and very careful adjustments of the black point and mid point sliders.

Dennis

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OK, thanks for the comments and tips: I had another go at the gradients on my brighter monitor, think I got most of it out including the dust bun-nies (must be on the camera filter, since I wasn't using any filters or correctors and it went with the camera not the scope...).

I also worked out how to feather one layer before merging. Here is the result. A bit better maybe?

m95m9626mar09003r.jpg

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I've certainly heard a lot of folk speak the praises of eXterminator - but I haven't bought a copy of it for myself - yet! I do my processing with a mixture of ImagesPlus, FocusMagic, and PaintShopPro (not Photoshop - I stick with PSP because I'm used to it since before I took up astroimaging).

Subtracting a blurred duplicate layer - with a bit of care and fiddling - seems to nail most gradients.

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