M31 with TS 100Q

[Xplode]

Some of you might recognise this image from a previous post, but this is a much improved version so i think this new image deserves to be in the first post in the tread.

Taken with TS 100Q, HEQ5 and unmodified Canon 6D from Hågår, Norway.

40 min consisting of 180s and 300s exposures at ISO3200. Stacked with bias and darks, but no flats.

Stacked and edited with Pixinsight and PS CS6.

 

I'd like to reduce the stars, but can't find a good guide on how to do this with Pixinsight, any help would be greatly appreciated.

 

Make sure to open it in fullsize on Astrobin

 

[ronin]

It's Green. :D

Actually good in Green.

[ollypenrice]

HI Ole, thanks for the PM and I'm happy to comment. Briefly this is a great image and one which will be easy to make even better than it is already.

As Ronin says, the green balance is a long way out but easy to fix. You could balance the histograms in Ps or run Colour Calibration in PI, or even just hit it with one click of SCNR Green which would probably do it.

It would be nice to persuade the stars to give a little more colour (often a problem with DSLRs and their lower well depth, but you have enough colour in the stars to work on them in post processing.) Noel Carboni (Pro Digital Astronomy Tools) has a first class set of actions on sale including 'Increase Star Colour' which pulls the colour from the outer part of the stars into their centres. It works well.

I think the stars are pretty tight as they are but Noel also has a 'Make Stars Smaller' action in the set. However, did you mask them for the stretch? PI has an excellent star mask generator which I take into Ps, myself, just because I'm more comfortable with Curves out of long habit. But you can obviously use it in PI stretching as well. On galaxies-in-starfields images I often do the background sky and field stars in a stretch of their own (using RGB rather than LRGB). The idea is to get the background sky to the same value as the main image but with small, colourful stars produced by using a Curves stretch which rises steeply but flattens very early. This gets the background up and keeps the stars down. Once the background is identical to the original (it must be literally identical) I paste the star stretch onto the main stretch but make it invisible. I then run the eraser just over the galaxies, removing the invisible top layer. When I make the top layer visible again I have the nice little field stars and the nice, well stretched galaxies in the same image. I don't think you can see the joins     but break it to me gently if you can!!!

Eg

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-ggp6h9q/0/O/M33%204%20scope%20ODK%20CoreWeb.jpg

http://ollypenrice.smugmug.com/Other/Best-of-Les-Granges/i-3D2Hw7s/0/O/M31%20Outer%20Halo.jpg

The outer halo of M31 is enormous and will only appear, in my experience, in very long subs. I used 30 minute luminance subs. Having said that, you have caught a lot of it as it is. For the core, you might be able to get a little deeper in. I made a special 'core layer' in which I applied insanely brutal contrast boosting just for the inner part. It's a balance between forcing the detail and keeping it natural. I like your core as it is but if you wanted to get a bit deeper I think it is there in you data.

Great image. I'm impressed by the 60Da as well, despite my passion for CCD.

Olly

Edit; this is with the TS 4 inch quadruplet? It really is impressive. Someone was asking about this scope but I couldn't remember who had posted an image with it. A budget Tak FSQ as long as you don't need such a big corrected field.

[Xplode]

Sorry for the green, i'm red-green color blind which is probably causing this.

I ran SCNR on the image and got this

[GuillermoBarrancos]

Much better! Really Nice capture Ole!

[Toymaster]

Great! Love these images....

Second one looking better. 

Ade

[ollypenrice]

Sorted! My first two processing steps with RGB are DBE and SCNR green. After that I find the colour looks after itself.

Olly

[Xplode]

Thank you 

I already use astronomy tools so improving the star color us easy. There is ok color in the stars in the RAW files which is probably thanks to the great dynamic range of the 6D, better than all other Canon DSLR's.

I didn't mask the stars at all when stretching, will give this a try both in Pixinsight alone and PS CS6.

My subs are just 5min, but high ISO which must have helped getting out the outer halo. Next season i think i should do some 10min subs to get even more of the outer halo.

There is definitely more detail in the core (thanks to the 6D's dynamic range), but i couldn't get it natural looking so i decided to leave it like this. Will definitely take more time to work on the core.

The 60Da is probably an ok camera, but not that's not what i have  For next season it will be an 6Da though

Yes 4" quadruplet from TS, i find it very good and has a very stable focuser that should work with heavy CCD's too. I have no idea how large the corrected and fully illuminated field is, the sensor of my 6D has a very nicely corrected field and it's almost fully illuminated to the edges too, any vignetting comes from the adapters i have used so the usable field should be bigger, but who has a camera lying around to test that?

[Xplode]

New version with more contrast and a little more color.

I think i'm coming to a point where it's really hard to improve on this image without adding more data...if only i had Ha data for it. 

Feel free to contact me if you have Ha data for M31 you are willing to share with me.

[ollypenrice]

Keep chipping away at it. In processing you get new ideas and can revisit the data. I bet you could find more star colour... (Sorry to be a pain!!!)

Olly

[Xplode]

No worries Olly, getting constructive critic is the best way to help someone improve their images

I will try to improve the star color tomorrow. I'm also gonna reprocess the image from beginning without darks.

If you want a go at processing some DSLR data i could give you a TIFF file to see what you can ahieve with my data?

[sologuitarist61]

Sorry for the green, i'm red-green color blind which is probably causing this.

I ran SCNR on the image and got this

Snap! I'm reg/green colour blind as well and thought the ifirst image was brilliant, but I can see that the second is better -  a great image Ole!