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M31 LRGB-Ha: a first full pixinsight processing

Avdhoeven

By Avdhoeven
in Imaging - Deep Sky

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Avdhoeven

Avdhoeven

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Last 2 weeks I was on holiday in Germany and there I had a great time together with a fellow astrophotographer. At a certain time he told me he had a TMB92SS with TS 2.5" flattener for sale. I always thought about this telescope because of its reputation and now I had the chance to test it thoroughly.

The first night was a bit of a disappointment as the stars in the corners were more or less eggs... I started looking on the internet and found that the ccd-flattener distance of 110 mm given by TS is not proper for the TMB92SS. In a French forum I found a message from somebody saying that the right distance should be 99,5 mm and so on the second night I gave that a try. The difference was remarkable. I had sharp stars almost until in the corners (there is still a small tuning left to do) and I was very happy with that. So I decided to buy the scope and now I'm the proud owner of a TMB92SS.

Now I had the scope together with my QSI583ws and wanted a nice target to make its first light. I quickly decided for M31 as this was always impossible for me, simply because I always had too much focal length (I worked with a C11 or a TEC140).

I started to make a series of images and started in Germany under quite dark skies with luminance frames. Weather unfortunately didn't allow full nights for imaging so I had to grab data over a number of days. In the end I had the following exposures:

19x300s L
3x300s B
9x300s R,G
9x900s Ha

Total: 5,6 hours

After seeing the quality of the dataset I decided to go for the first time for a full processing in pixinsight (except for a few small things, like high-pass sharpening that I always do in photoshop). Following the videos from Harry's astroshed this was a real delight. I never got so much detail from my images before.

This is the final result which I'm very happy with. I certainly will have a lot more fun with this scope, that's what I'm sure of.

Full resolution

post-16343-0-45002800-1407418419_thumb.j

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Dave_D

Dave_D

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I like the image but the core does have a 'Pixinsight' look. If you are handy in Photoshop I'd be inclined to use both. This is isn't a religion. You can worship two gods!

Olly

Excuse the noobines, but what is a 'PixInsight' look?

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ollypenrice

ollypenrice

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Excuse the noobines, but what is a 'PixInsight' look?

Heh heh, hard to define but you know it when you see it! PI uses some routines which do impose a certain look. Dennis, well known elsewhere, describes it as looking like a human brain. I'm only suggesting that this applies to the very core in this impage, which I do like.

I think we all agree that processing should look like it hasn't been processed!  :grin:

Olly

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Avdhoeven

Avdhoeven

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Olly, I understand what you mean. It's a bit 'flat' because of the HDR routine used. Do you think this is better? This one has been combined with my PS processing. Also the colors are a bit more pronounced now. I wonder if this is ok or too much...

post-16343-0-48330900-1407442373_thumb.j

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harry page

harry page

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Hi

You have made a good start , and there is no need to resort to photoshop :grin:

I have spotted that your colour has drifted a bit try and use background neutralization again , also a bit of LHE will help lift the image - lastly a bit more saturation wont hurt

If you find HDR wavlets leaves it a bit flat for you just apply a lum mask ( adjusted as ness ) to restrict the effect of HDR wavlets

Difficult with a jpeg but you get the drift

Harry

post-4081-0-09396900-1407444905_thumb.jp

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ollypenrice

ollypenrice

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Better and better. Harry did a good job there.

Saturation is a last resort tool in my personal toolbox. There's a very good Ps routine (not picking a fight with Harry here!!!  :grin: ) which intensifies colour with low noise increase. It does work best on the reds though.

Make two copy layers. Set the top one to blend mode Soft Light and flatten. It looks awful but wait!

Set the new upper layer to blend mode Colour. Give it a blur of about 0.6, choose the desired opacity and flatten.

On galaxy images you don't have to use the same stretch for the galaxies and field stars. I never do. I prefer an RGB-only (no luminance) starfield given a soft stretch to keep the field stars small. It is easy to combine this with the main image in Layers.

You have an excellent M31.

Olly

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Avdhoeven

Avdhoeven

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Hi

I am on my works computer , but there seems to be a slight green tinge - try SCNR   ( std in my work flow even if I think there is no green :)  )

Harry

 I tried but I don't see a difference any more... 

This is the result including Olly's star field hint.

post-16343-0-88459100-1407488783_thumb.j

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Earl

Earl

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Excuse the noobines, but what is a 'PixInsight' look?

Thats a thread all of its own :) I use PI as i know little about PS, hoever I need to learn PS to make my images look the way I want as PI does not do what I want after a point.

Very Nice M31 :)

If you do some MT and bring the stars down a touch i think you will be much happier still. ( I tend to like smaller stars tbh)

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Avdhoeven

Avdhoeven

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I fully agree. The processing makes the image and that can take a lot of time. I slowly start to understand pixinsight more and more, and it's strong, but can be easily overdone. Imaging is one thing (and a very important part!), but then it only starts... :)

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pietervdv

pietervdv

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Better and better. Harry did a good job there.

Saturation is a last resort tool in my personal toolbox. There's a very good Ps routine (not picking a fight with Harry here!!! :grin: ) which intensifies colour with low noise increase. It does work best on the reds though.

Make two copy layers. Set the top one to blend mode Soft Light and flatten. It looks awful but wait!

Set the new upper layer to blend mode Colour. Give it a blur of about 0.6, choose the desired opacity and flatten.

On galaxy images you don't have to use the same stretch for the galaxies and field stars. I never do. I prefer an RGB-only (no luminance) starfield given a soft stretch to keep the field stars small. It is easy to combine this with the main image in Layers.

You have an excellent M31.

Olly

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