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M81, M82 & NGC 3077

gnomus

By gnomus
in Imaging - Deep Sky

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gnomus

gnomus

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Posted

This is three hours of RGB - 6 x 10 mins of each.  I had to struggle with some odd gradients in this one.  This was helpful though, since it indicated to me that my light box needed some modification (my flat frames had a distinct horizontal line in them).  I also think that I have some LP when imaging in a northerly direction - I will add my LP filter into the chain in future when I point north.

I don't like the composition, and I am not entirely sure that this was an appropriate target with my imaging equipment, but ho-hum.  I am fighting the urge to over-process, but maybe this looks a little too 'bland'.  

I am thinking about adding a couple of hours of luminance to this and maybe some Ha to bring out the red bits especially in M82.  What do folks reckon?  Please feel free to offer your honest criticism.  That is my main aim in posting.

post-39248-0-32077700-1442295503_thumb.j

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Sleepy Kiki

Sleepy Kiki

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Thats a really good image! I think your data and processing looks great and clean so there might be more to get out of it before it gets 'over processed' but personally I like images that aren't overcooked. I agree that this pair will benefit from some HA and maybe a touch of sharpening with the stars masked out.

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MartinB

MartinB

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Looks good to me.  I always find my images to be a bit anaemic preprocessing.  I guess that's a true reflection of the photons coming into the scope.  As a result this has a "natural" look and is certainly fine as it is.  Some people like a bit more colour and that's just down to taste.  However, boosting the saturation can help pick out the different areas of the galaxy and give more insight into the structure, as you've already mentioned with regard to the Ha areas.  Whenever you boost saturation you are adding noise so go steady.  

You could spend hours of imaging time gathering a little splodge of red Ha, not sure it's worth it at this focal length (well it wasn't when I did it!)

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gnomus

gnomus

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I think that looks great as it is.

You are probably right, but I cannot help myself.  

I collected 8 x 10 minute exposures of Luminance last night.  Why 80 minutes you might ask?  Well at the start of the session my wife suggested that we turn the dew heaters on.  I confidently predicted that we would not have any problems with dew.  Guess what happened 80 minutes later?

post-39248-0-15660300-1442415370_thumb.j

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gnomus

gnomus

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Nice Image Gnomus.

Have to admit I prefer the version with the luminance. Think the RGB only looks a little soft for my taste and the L crisps it up a little.

Sarge

Thanks Sarge. When I first added the L to my RGB, I did so in PixInsight. The result was wild - really bright. I wonder if I overdid the HDRMultiTransform and LHE. Am I supposed to 'Linear Fit' the Luminance channel to my RGB channels (I do linear fit the RGB channels to each other)? Anyway, in this case I added the L as a layer in Photoshop, set blend to Luminosity and dialled the opacity back to around 25%. I'm never very sure how much I should 'push' these images - I'm trying to reign myself in a little.

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The_Sarge

The_Sarge

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Gnomus,

I'm new to this so certainly no expert. I so far have tended to do similar in Photoshop but opacity more like 70% for my M31 posted a week ago. I don't have pixinsight.

Ultimately when you have all the techniques in your toolbag it all comes down to personal taste.

I've still got an incredible amount to learn that's for sure.

Sarge

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gnomus

gnomus

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The galaxies do look a lot better (warmer) in your last processed image, but the background to me looks just a tad to dark, still a great image though go on give it one more process?

An extremely good point Martyn.  I did think this myself.  All right ... you talked me into it.  How about:

post-39248-0-55579400-1442593755_thumb.j

There are also a couple of "faint fuzzies" below and below and right of M81 in the last image that are much clearer than the second and almost unidentifiable in the first.

James

Yes I'm glad you noticed them.  I cannot find out anything about them in Sky Safari or any of my star charts - does anyone have any ideas?

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gnomus

gnomus

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Very nice images Gnomus,out of curiosity how bad is your LP in Nottingham.

Interested in what your single 10 minutes subs look like to compare.

Kenny

Notts not Nottingham Kenny.  I don't think it is too bad generally, but I do have to shoot over the village if I point north.  The sky seemed dark enough but in the processing I found some mild dark- reddy-orange patches which I have tried to eliminate in processing (but which I can still see).

Here is one 10 minute Luminance sub - it has, however, been calibrated (with darks, flats and bias) and registered but I have not removed the LP with DBE or anything like that.  I don't know if this helps you or not (unfortunately I seem to have temporarily mislaid the uncalibrated files).

post-39248-0-43547600-1442594524_thumb.j

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