M101 - difficulty processing

[el_hop87]

Hi everyone,

I am new to StarTools and still have a lot to learn - at the moment I am having difficulty processing the M101, Pinwheel Galaxy, and unsure if it is the image itself or my processing skills that are the problem! I go through the process but the image itself looks heavy with gradient and the colours are not working out either.

To take the image I used the AZ GTI, Nikon D5200, SW Evostar 72ED, IDAS P2 filter. Each exposure was 20 seconds, 1 hr 52 mins total exposure time, 20 darks and 20 flats. I stacked the image in DSS and turned into FITs image in Siril prior.

I have attached a JPEG file of the image

M101.jpg (271.95 KiB) Viewed 5831 times

and would hugely appreciate any guidance on what I am doing wrong.

Many thanks,

Elly

[Carles]

Hello Elly, and welcome to StarTools!

Is that Jpeg the file processed already ? If so, first of all, you need to crop before doing much. Also it seems there's vigneting.. did you use Flat frames?
I've AutoDev your file and got this

M101- cropp.png (62.83 KiB) Viewed 5829 times

Can't do much with it. I think first you should get your calibration frames (Flats, darks and bias/offsets OR dark flats).
Also check the recommended settings for DSS, including disabling any sort of White Balance.

in the Download section you have the Unofficial manual full of information, tips and tutorials. There's the section to prepare your files depending on the software you are using. Or in the main website "links and tutorials" you have similar info too

Try setting DSS as per manual /tutorials and stack again and see how it goes ^^

Regards

Carles

[el_hop87]

Hi

Thank you so much for your reply! - I think the issue maybe the JPEG format as in the FITs version it appears differently (I think the FITs file is too big to attach to this post as it won't allow me to).

After an initial bin, stretch, crop and wipe I am able to get the attached image, but there seems to be a lot of gradient in the sky and M101 itself which remains throughout the rest of my processing and into the colour module.

Is this to do with the image itself or am I missing something in the processing?

Also, I have used lights, darks and flats in the stacking.

Many thanks again.

Autodev M101.png (74.96 KiB) Viewed 5828 times

[Carles]

Oh I see, yes it looks better.
you can use one of those web services to post the file and copy the link here.
( Megaupload, wetransfer...and so on )

But I still see vigneting. you should check the flats.
And, did you stack all the images or selected the best ones? You can check the "Score" in DSS after registering the images to get an idea of the good ones. Or you can use the "slider histogram" on the top right and stretch visually (it doesn't affect the file nor the stacking) in order to see more or less the field of view, then with that set, go through the sub frames and see if you had clouds moving through or something similar...

Aside from that, I don't know what else. You've mentioned you used Siril after DSS ? any special reason? Usually the file saved from DSS is OK for StarTools to work with.


Regards

Carles.

[el_hop87]

Thank you!- yes, I will take a look at the flats and try to see if there is any issue.

I only used Siril because DSS seems to save the stacked image as TIF which isn't compatible with StarTools - I hadn't realised that DDS could do the things you mentioned so will look into this too.

Thanks for the suggestion of copying the link to the stacked image using those platforms, please find the FITs image here:
https://www.dropbox.com/s/hqevrwhgug7lx ... 1.fit?dl=0

Another issue was the light from the large moon (as lovely as it was!) , so this may have caused an issue too.

I will try stacking the subs again and focus on the things you mention to see if that solves the problem!

Thank you again!

[Carles]

No problem ^^
happy to help

You have to check the manual, or the DSS settings on the website. As you can change the save format either TIFF or FIT
and other things that would be good to check and change accordingly.

https://www.startools.org/downloads/uno ... sh-manual-

and
https://www.startools.org/links--tutori ... r-settings

^^

Regards

Carles

[Carles]

Also, I have used lights, darks and flats in the stacking.

Autodev M101.png

Hi again, I'm looking at your file. you should take Bias frames too. there's some banding all over the image
that should get better with Bias /dark flat frames including darks and flats.
I've used
AutoDev->Bin->Crop--> Wipe (uncalibrated) --> FilmDev -- Contrast- Color - Super Structure - Track off denoise.

101-.png (423.13 KiB) Viewed 5821 times

maybe if you "clean" the image with calibration frames can get more out of it. Even though, it needs more exposure
I am doing this object too and so far have 4h...and not good enough either.

Hope it helps ^^

Carles.

[el_hop87]

Hi Carles,

Thank you very much! - that is much better than mine and really useful to know your steps!

I think working on the calibration frames is definitely the next step forward.

Just attempted for a re-edit and hopefully it will come out a little better this time.

Thanks again!

[happy-kat]

if you used the super structure module before denoise and create a mask over your M101 you could use the dim small preset to even the background tone out, then revisit colour module and balance the colours out.

[el_hop87]

Thank you! - I will try this