StarTools

I sat on these data for several months. When I started collecting subs I set exposure for ~400 saturated pixels (120s high-conversion gain), but almost all of those pixels turned out to be in just the 3 or 4 brightest stars. Every time I tried to process, those stars looked just awful.

With the '16-bit tranches' in the latest beta I figured now was a good to to revisit the data. I also realized that I could cheat a bit - because the "nebula" parts of the image are quite small. So I processed twice and Layered the two together. For the Owl & Surfboard I used 12-bit Optidev. Color calibration was from the galaxy. I used the same color weights for the star-processing iteration - but straight CIE for the galaxy/nebula and RGB ratio / CIE for the stars. I still need to tweak a bit to get the backgrounds to match better - there's a couple of spots where you can see the layering still.

5.3 hours OSC, AT130EDT Risingcam IMX571c. I collected a few hours of duoband, but it didn't seem to reallyenhance the image much so I left it out. I'll hopefully add more time next winter.

That is a very nice widefield. Like it. You even got a red rim around M97. And M108 stands out very well too..

i tried M97 once with my DSLR and L-enhance i believe. It was a total failure. Still does not understand what went wrong. Shame, cause it is a very nice object.

Something to consider for a redo but since the weather is awfull, there is no chance to take any capturing. Besides i am still fiddling with my RC8 and guiding , but also there the weather does not permit me to troubleshoot any further..;

Thanks, Freddy!

It is a nice object, but as you say "widefield" even at 910mm. That's why you went with the RC8 - all those even-smaller PNs. Too late to add more this year, really. Plus, I mounted the little AT65EDQ for tonight.

dx_ron wrote: ↑Sat Jul 13, 2024 4:14 pm With the '16-bit tranches' in the latest beta I figured now was a good to to revisit the data. I also realized that I could cheat a bit - because the "nebula" parts of the image are quite small. So I processed twice and Layered the two together.

Hi Ron, yes I'm also glad that we now have a means to mitigate this awful looking stars. I suppose with 16-bit tranches you had problems to get the DSOs bright enough and therefore decided to process twice and then layer together? Yeah, that seems to be the downside of this 'tranches-solution'. I still haven't reread Ivo's explanations. I wonder if this loss of brightness (aka less allocation of dynamic range to the mid-tones) is simply a consequence / by nature or more of a collateral damage of this 'tranches-solution'?

Dietmar.

decay wrote: ↑Mon Jul 22, 2024 7:11 pm
I wonder if this loss of brightness (aka less allocation of dynamic range to the mid-tones) is simply a consequence / by nature or more of a collateral damage of this 'tranches-solution'?

Hi Dietmar,

Yes, I think you put it very well there. I think that's why Ivo resisted it originally - dynamic range is kind of wasted at the very top. Except that the star cores look awful... So, yeah, I decided to "have my cake and eat it, too" (an American expression) and let the galaxy and nebula have as much dynamic range as possible and also have prettier stars.

dx_ron wrote: ↑Tue Jul 23, 2024 1:23 pm (an American expression)

Wait...wut?

Anyway, I haven't even played with the new version yet. If my car rebuild ever gets done hopefully I'll be able to clear up more astro time. And like Dietmar I'm not sure I have all the mechanics of this stuff understood yet. Seems like maybe a difficult problem of curve control? Sufficient tranches to smooth out the cores of overexposing star shoulders pushes bright DSO data too far down, thus being perceived as too dim?

Mike in Rancho wrote: ↑Tue Jul 23, 2024 3:10 pm dx_ron wrote: ↑23 Jul 2024, 15:23
(an American expression)

Wait...wut?

Well, guys - there are maybe thousands of miles between your homes - so why not having local phrases?

My contribution: 'Wasch mit den Pelz, aber mach mich nicht nass.' - more or less literal translation (finest 'German English' ) : 'Wash my fur' (I would like to have excellent looking stars, please.) ', but don't get me wet.' (And of course don't dim my DSO's!).

(Probably a cat is meant.)

Dietmar.

I suppose it is technically an English expression - but I thought universally understood here in the good ol' U S of A.

I'm not convinced yet that "too dim" is non-recoverable - but I am concerned about a squashing of dynamic range in the DSO-zone. Which is why I did the dual-process thing here.