M51 and some other wee galaxies

[powerlord]

More and more impressed with this TS-Photon 150 the more I use it.

This was shot last night - an hour of each R,G,B and 25 mins of Ha.

Processed in Siril, startools and affinity.

I've annotated it with astrometry.net

some really tiny galaxies picked out there.

 

 

 

[vlaiv]

What happens to the stars in the processing? Why do they end up like this:

[powerlord]

topaz denoise. Sorry - not a star peeper so didn't really notice. I might got back and correct.

stu

[powerlord]

voila.

[vlaiv]

2 minutes ago, powerlord said:

voila.

Not seeing it

6 minutes ago, powerlord said:

Sorry - not a star peeper so didn't really notice.

I appreciate people don't really zoom in to see their data at 100% - but if you are going to post it at full resolution - well, then don't be surprised if people want to look at the data at 100% in order to see smallest detail capture.

[powerlord]

well, that's better than before yes ?

what you see there, is what I got out of stacking with APP. seems to only be some that are 'doubled'. maybe stacked a few dodgy files I supppose.

Edited January 14, 2022 by powerlord

[powerlord]

12 minutes ago, vlaiv said:

Not seeing it

I appreciate people don't really zoom in to see their data at 100% - but if you are going to post it at full resolution - well, then don't be surprised if people want to look at the data at 100% in order to see smallest detail capture.

wasnt having a go, just genuinely didn't notice. As I said above - might be I stacked a frame I shouldn't have stacked. not stacking it might sharpen M51 too, so I'll have a look tomorrow - see if I can find the culprit - it was 60 sec subs - all 185 of em, so i skipped through them pretty quickly (prefer an eyeball check before i put them into APP). chances are I missed a rubbish one or two.

Edited January 14, 2022 by powerlord

[vlaiv]

11 minutes ago, powerlord said:

wasnt having a go, just genuinely didn't notice. As I said above - might be I stacked a frame I shouldn't have stacked. not stacking it might sharpen M51 too, so I'll have a look tomorrow - see if I can find the culprit - it was 60 sec subs - all 185 of em, so i skipped through them pretty quickly (prefer an eyeball check before i put them into APP). chances are I missed a rubbish one or two.

I think it is something to do with processing.

Aside that those stars are funny shaped and somewhat large - they are processed in the way I would not expect and that seems to be the trend - they look "flat" as if they don't have a core.

Look for example this:

That star has brightness "stopped" somewhere around grey - like you did not want that star to shine and be bright.

That star is very bright - yet brightest pixel is something like 170/255.

Skirt / halo and spikes around the stars should be faint - yet they are equally bright. That sort of makes flat appearance.

[powerlord]

oh that is just intentional. just liked them that way. but the other stars above are not 'unprocessed' - just as stacked.

but yeh, some of the brighter ones, I pulled back in after dimming the others. There's no core, because that's what the stack was - maxed out. I just popped them back in to give the composition some framing.

I'm not in any way aiming for scientific accuracy here.

stu

[powerlord]

So.. turns out al the subs are like that. collimation thing ?

here's one sub:

[vlaiv]

2 minutes ago, powerlord said:

So.. turns out al the subs are like that. collimation thing ?

First check orientation of elongation and see if they align with RA or DEC.

Compare that to your guide log (if you have it) and see if there is possibly something in the guiding that will cause these. Also - see if it could be flex.

Best way to check for flex is to see if there is constant drift between subs (compare star positions over multiple subsequent subs).

In the end - check collimation.

 

[ONIKKINEN]

8 minutes ago, powerlord said:

So.. turns out al the subs are like that. collimation thing ?

here's one sub:

Looks like the kind of artifacts i get when my newtonian is not properly cooled down and tube currents are still present. Did you image straight away from setting up outdoors or wait a while? Sometimes it can take about an hour for my 200mm to be fully ambient and these artifacts go away. Check the your early subs and compare them to your last ones, if the early ones look like this but the last ones are clean this was caused by tube currents.

[ONIKKINEN]

4 minutes ago, ONIKKINEN said:

Looks like the kind of artifacts i get when my newtonian is not properly cooled down and tube currents are still present. Did you image straight away from setting up outdoors or wait a while? Sometimes it can take about an hour for my 200mm to be fully ambient and these artifacts go away. Check the your early subs and compare them to your last ones, if the early ones look like this but the last ones are clean this was caused by tube currents.

Here is an example i found from my catalogue of subs:

First one is straight after setting up on a night when i did not have time to cool down the scope properly. Second is 2 hours later.

[powerlord]

Thanks. No those were the last of the night, so scope had been out for hours by then.

Guiding was good generally, but was a bit worse at that point I think.. I'll check logs.