M13 with double integration time

[fmeireso]

One of the many versions now i have on M13
174 subs of 90 sec, 53 bias and 104 flats.
130 mm TS Photoline apo F/7 with FF

M13Cropped.jpg (393.66 KiB) Viewed 4418 times

[dx_ron]

Very nice, Freddie! You use a dslr? It's interesting that you can get away with 90s subs at f/7. Could use maybe a touch more de-ringing on some of the stars?

[fmeireso]

Thanks.
Yes even with 90 subs it was nice image.
Thisone is better of course because of the longer integration time say about the double.
I use DSLR Canon 800D, i have bortle 5 skies.

Stacked in PI, but processed of course in Startools. I did not even tweak it in GIMP this time exept for the cropping but i could that have done in ST too actually.

The flux module gives it that sparkling effect. The stars always a bit of a problem allthough on this one not bad at all imho...

[fmeireso]

About the 90 sec subs : just no longer subs to not overblow the core.
I see many globs with a too much bright center. Counts also for other objects like M31 and even more M42.

I never take longer subs then3 minutes and that is on emission nebulae.

With my mono DSLR this is another ball game, there at least 6 to even 10 minutes subs are needed to cath the HA

[decay]

Nice image, even the outer fainter stars are quite bright and well coloured . The long integration time is clearly visible at the end.
On my PC screen the area between the core and the outer regions shows a slight green cast. On my smartphone, however, the green cast is nearly invisible . I’ve been struggling with the colour balance on my own image of M13 for a few days now; it’s a real pain.
Why did you use the flux module? Is it for sharpening? What would the image look like without using this module?

Best regards, Dietmar.

[fmeireso]

The flux module gives the glob ,any glob, a sparkling more brighter effect. bit tedious, cause too much can ruin the stars. I try to make a mask of the glob, enlarge it and sharpen it via the flux module. It gives stunning effects

Check my astrobin for a couple examples, more blue, but actually i like that more
https://www.astrobin.com/users/Fmeireso/

The green cast well, i see it also a bit, allthough Maxrgb showed no green at all...so where does it come from..? And on different screens it always looks different. Last week i had some friends viewin my M13 on their mobiles, they were all different, mine more blue, anotherones more red and another more greenish, all Androids phones...it is what it is, i guess

[Mike in Rancho]

Good to get the extra integration there, Freddy.

I think I'm kind of with Ron on this one though, the stars seem to have ringing or concentric coring in them, and not just your standard dark shadow ring either. I'd probably use a star mask and give those cores a slight blur in layer.

The sparkly looks really neat, but I'm wondering now if it is actually a true feature. After seeing your posts on the globs I went to look through the documentation on flux usage. Seems to be designed for gas knots, so...nebula?

Again all good if that's the look you prefer, but I'm kind of thinking it might be giving you hundreds of tiny bright star dots that aren't real stars.

[LuckyEddie]

Personally I like the flux sparkle effect a lot. I've just tried it out on my own M13 and to my eye it makes a fantastic difference, as long as you don't over do it.
I don't think the flux module can invent stars. Pixel peeping between a before and after 'fluxed' image it appears to be sharpening, and therefore brightening, real existing dim stars.

[fmeireso]

That is exactly what happens...

Many images of globs hold alot of fine stars, but they are dim like a disabled button in Windows so to speak. The flux sharpening boost them, it does not invent new stars.
But indeed you might run into artifacts, and you really have to keep an eye on the slider on how much to apply...
I seem to get much likes , on CN but also on a Dutch forum, so i think many people seem to like it....myself included

EDIT : i discovered this by coincidence, cause indeed the flux module is more for sharpening nebulae. And it is advised to create an inverted starmask if you use it. So i assumed the result would be horrible, i was playing around at the time. But much to my surprise, if applied with care, a stunning result is the outcome.

[decay]

Freddy, I took a look at your astrobin images . Especially I like your shots of the Rosette Nebula and of NGC 1499. It's astonishing what a great red sensitivity your unmodded EOS 800D shows. My 2000D is nearly blind for red. And one fine day I will also afford such a great optics like you own

Regarding the use of the flux module I tend to be more conservative. Of course, it gives stunning results and of course, the aim is to get nice looking results - but for myself I would like to preserve as much of the documentary value as possible. (But of course, your image looks amazing! )

I totally agree about the annoying dim stars looking "like disabled buttons in Windows" - I'm not sure if this is a problem of data acquisition or of post processing . I tried a lot but at the end they are mostly desaturated

Best regards, Dietmar.