m5

[alacant]

Hi everyone

Plagued ATM with bright stars in or near to the FOV. A few nights a go it was m109; spring Alintaks waiting to pounce upon the unwary imager. 

We managed 19 frames on this one. Really intrusive star at top left. Had a go at minimising it but made a total mess. By then however I'd spent my 15 minutes of processing patience. So it remains. Mess, noise and all. Much easier to just cheat and remove it altogether!

Thanks for looking and do post your dslr m5s.

 eos700d @ ISO800

 

**EDIT. Here's the cheat version. Even managed a bit of artificial colour. I am supposed to be cheating after all...

 

 

Edited May 9, 2021 by alacant

[Robculm]

Hi Alacant, Can I ask what exposure length you were using? Thanks, Rob

[alacant]

1 minute ago, Robculm said:

exposure length

180s

HTH

 

[Robculm]

Thanks. So how do you keep the centre brightness down / keep the detail? Is that in processing? Or it's like that on the raw data? 🤔

[alacant]

30 minutes ago, Robculm said:

centre brightness

Hi

StarTools' HDR, You could do something similar by developing one stack less than the other and merging the layers.

What software do you have?

Cheers

[Robculm]

Siril (thanks to your recommendation :-)) for stacking (sorry still didn't learn the process yet, just using the OSC_Preprocessing), then usually green noise removal, photometric colour calibration, background removal & finally the 'autostretch' & save as TIF.

GIMP for final editing, with the Pyastro plugins, although to be honest, the GIMP end of my processing is still a bit random! If I'm lucky I get a reasonable starting point from Siril & there's not much to do in GIMP, maybe some saturation, purge red sky, contrast & export as JPG... I tried doing a heavy gaussian blur on the M13 image & subtracting a little of that from the main layer, but typically with GIMP, the more I do the worse the result...

 

[Robculm]

Here's my M5 attempt from early April. This was 180s, ISO400, but only about 15 frames.

[alacant]

57 minutes ago, Robculm said:

GIMP for final editing

Yeah, GIMP will do it. 

1 hour ago, Robculm said:

gaussian blur on the M13 image

It's best if you have just two layers. The one you have posted and a second far less aggressively stretched version. A mild arcsin in Siril should do it. Mask and then paint ieith a fuzzy brush in black over the core area to reveal the stars. 

Another way is to take short exposures, say 10s or so so the centre remains as separate stars. Stack that for the core layer.

HTH

[Robculm]

Thanks, will have a play with the 2 layer approach :-).

Being that I haven't properly learnt how to use Siril yet, I can't try the tacking of different exposures, as I assume you need to stack them separately & then stack them together?!

 

[alacant]

25 minutes ago, Robculm said:

stack them together

Hi

Assuming the core is over exposed completely in your original stack and you've gone instead for the 10s and 180s approach. Please note that very few targets need this method and your M5 stack may well be a candidate, but anyway...

No. Stack them separately. Place the separate r_pp_stacked  files in a separate folder, set that as working directory and hit register. The resultant r_ prefixed files are now your two separate layers. Stretch them (in Siril if you like) then layer mask them in gimp.

Or get a copy of StarTools and just enjoy the view:)

Cheers

 

 

 

Edited May 9, 2021 by alacant

[Robculm]

👍

[Mr Spock]

Nice core detail 👍

[scotty38]

Great picture and I was scratching my head for 5 mins wondering why it looked so different to my image of M13 🤣