The seahorse in Cepheus

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Stefan B
Posts: 376
Joined: Sat Oct 31, 2020 8:59 pm

The seahorse in Cepheus

Post by Stefan B »

My favourite constellation Cepheus is already high up in the (northern) skies and so it's dark nebula time. Inspired by a recent image by @Carles I aimed for the seahorse nebula aka Barnard 150. Almost 10 hrs accumulated over three nights during this disappointing summer weather.

Image

Pretty minimal workflow for me. Skipped HDR completely. SVD almost had no effect. No Saturate preset in SuperStructure this time. But thought the result is fine as it is. If you have any tips and tricks for processing dark nebulae I'm eager to hear it :)

See https://www.astrobin.com/9audh1/0/ for details.

Regards
Stefan
decay
Posts: 315
Joined: Sat Apr 10, 2021 12:28 pm
Location: Germany, NRW

Re: The seahorse in Cepheus

Post by decay »

Simply awesome, Stefan :confusion-shrug: :bow-yellow: Yes, probably not much to do for HDR module due to the appearance of this dark nebula. Did SV Decon had no impact to the stars too? Stars do look like needles, like always or often for you. :thumbsup: Even the brighter stars are pin-points. Have you used the Shrink module? And with which settings? And I wonder why your stars show these nicely coloured halos, reaching out so far into their surroundings. :think:

Best regards, Dietmar.
Stefan B
Posts: 376
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Glad you like it, Dietmar! And thanks for your feedback.
decay wrote: Tue Aug 15, 2023 4:52 am Did SV Decon had no impact to the stars too?
It did, but not on as many stars as I am used to. Especially fainter and smaller stars were unaffected. Maybe my sampling was different and contained brighter stars than usual. The bright stars were fine as you already noticed.
decay wrote: Tue Aug 15, 2023 4:52 am Have you used the Shrink module? And with which settings?
Yes, Shrink is an important part of the workflow for me :) I used the Tighten mode with 15 (instead of 10) iterations and also bumped up the sliders for color tame and halo.
decay wrote: Tue Aug 15, 2023 4:52 am And I wonder why your stars show these nicely coloured halos, reaching out so far into their surroundings. :think:
Yeah, that seems to be a deficit of my optical train. I see that (too) often. But I appreciate that you call them nicely colored ;) I guess these halos are just part of my train's PSF. If you have bright targets the outer halos don't get stretched too much so that you don't notice so badly. But if you stretch agressively as was the case here (due to the dark nebula...) also the halos get stretched. They are real detail of course for ST.

If you then shrink the stars' cores the halos appear even bigger (compared to the cores). But I am just guessing here.

Part of the problem may be me Baader MPCC which is rather on the cheap side. The GPU CC (@Startrek has one) is said to produce smaller stars but I didn't buy one till now...

Bad collimation may also be part of the problem. Maybe I can post something on the that in the coming days.

Regards
Stefan
decay
Posts: 315
Joined: Sat Apr 10, 2021 12:28 pm
Location: Germany, NRW

Re: The seahorse in Cepheus

Post by decay »

Stefan B wrote: Wed Aug 16, 2023 7:34 am Yeah, that seems to be a deficit of my optical train. I see that (too) often. But I appreciate that you call them nicely colored ;) I guess these halos are just part of my train's PSF.
First of all: I indeed like this look of some of your images having these coloured halos (I often do that :roll: , but in this case it was not meant to be ironic!). I was wondering if this was done with some kind of post-processing. It looks like only the chrominance signal is smeared / spread out whereas luminance is not:

2023-08-19 10_35_02-x29rj-tf6TT4_16536x0_ieTZ0INm.jpg (JPEG-Grafik, 3588 × 2345 Pixel) – Mozilla Fir.jpg
2023-08-19 10_35_02-x29rj-tf6TT4_16536x0_ieTZ0INm.jpg (JPEG-Grafik, 3588 × 2345 Pixel) – Mozilla Fir.jpg (32.46 KiB) Viewed 18006 times

So like television signal transmission, having lower bandwidth for chrominance as the human reception focuses on luminance. I wonder if this could be a result of processing in ST, as there is LLRGB processing going on behind the scenes. And perhaps the more aggressive the stretching, the greater the effect?

How at all: No need to buy a new coma corrector. Everything is fine as it is! :mrgreen:

Best regards, Dietmar.
Mike in Rancho
Posts: 979
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: The seahorse in Cepheus

Post by Mike in Rancho »

Nice job. The dark nebula shapes are really standing out against the lighter dust. :D

I don't really see any halos, or any appearance to the stars that seems much different than the way mine often turn out. :confusion-shrug:
Stefan B
Posts: 376
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Yeah, not too bad. But sometimes I see images like this (https://www.astrobin.com/r732ag/)

Image

and ask myself...how? The stars are extremely defined. Point SPREAD is barely the right word for this star appearance. Or are the stars actually bloated here and using ST the stars would look like in my image since they wouldn't get overstretched?

Regards
Stefan
Mike in Rancho
Posts: 979
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: The seahorse in Cepheus

Post by Mike in Rancho »

Stefan B wrote: Mon Aug 21, 2023 8:34 pm Yeah, not too bad. But sometimes I see images like this (https://www.astrobin.com/r732ag/)

Image

and ask myself...how? The stars are extremely defined. Point SPREAD is barely the right word for this star appearance. Or are the stars actually bloated here and using ST the stars would look like in my image since they wouldn't get overstretched?

Regards
Stefan
Hmm, I dunno. He doesn't say much and some info is missing. And even if you look at some of his other uploads, I think it's all in Swedish. ;)

He gets a lot of recognition though, it seems.

If I were to guess, I would say maybe the galaxy and star field is mashed together via the whole star removal thing. I'm not sure the stars match the stretch of the galaxy. In fact, the whole field seems too tame for 6 hours with an 8" f/5. Looks kind of like when I did M104 with DSLR at only 2.5 hours through an f/9 frac. The number of stars, anyway. He should have lots and lots of stars everywhere, and brighter.

I will have to try this one again with the reflector. Think we have to wait a while for Virgo to return though.
fmeireso
Posts: 305
Joined: Mon Sep 28, 2020 8:46 pm
Location: Belgium

Re: The seahorse in Cepheus

Post by fmeireso »

Hi Stefan,

I think it is a great shot!. Thisone i surely have to put on my wanted list. Might be more difficult as my skies are not as good as in 'Feuchtwangen'.
Ha i know where that place is now...As said i passed it on my way to Austria. Lovely region :thumbsup:

Taling about skies, Austria has great skies, Must be something between bortle 3-4. The milky way was just flabbergasting...unfortunately there were stupid local lights from houses, but other then that it was great. There was no skyglow...

Freddy
Stefan B
Posts: 376
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Hi Mike,
Mike in Rancho wrote: Tue Aug 22, 2023 6:22 am And even if you look at some of his other uploads, I think it's all in Swedish. ;)
It's German ;) He is an Austrian astrophotographer who has a YouTube channel which explains part of his recognition. When I was binge watching AP videos, I frequently watched his. I guess you and Ivo wouldn't have been too impressed by his workflow since then he used APP for stacking, gradient removal and initial stretching and then went on to PS. But still I liked the look of his images. They had a natural look and didn't look too overprocessed. Especially his stars weren't reduced too much.
Mike in Rancho wrote: Tue Aug 22, 2023 6:22 am If I were to guess, I would say maybe the galaxy and star field is mashed together via the whole star removal thing.
I don't think so. He only recently switched to PI and the XT tools. The image is from 2020. Don't think that applies.

Anyway, it's just one of many examples I see out there and am thinking...how? Am I doing something wrong?

But that said, meanwhile I am much more satisfied with my stars. Not too much to complain here. But after Dietmar mentioned it I could not be not complaining ;)

Regards
Stefan
Stefan B
Posts: 376
Joined: Sat Oct 31, 2020 8:59 pm

Re: The seahorse in Cepheus

Post by Stefan B »

Hi Freddy,

thanks! Don't get me wrong - I like my seahorse. Also with regard to the stars it's one of my better images. So all fine ;)
fmeireso wrote: Tue Aug 22, 2023 6:30 am Thisone i surely have to put on my wanted list. Might be more difficult as my skies are not as good as in 'Feuchtwangen'.
Ha i know where that place is now...As said i passed it on my way to Austria. Lovely region :thumbsup:
You should definitely give it a try! Might be more rewarding than you think. And yes, I of course remember you mentioning that you passed my hometown! Glad you enjoyed the travel!
fmeireso wrote: Tue Aug 22, 2023 6:30 am Taling about skies, Austria has great skies, Must be something between bortle 3-4. The milky way was just flabbergasting...unfortunately there were stupid local lights from houses, but other then that it was great. There was no skyglow...
I bet the skies are great. Unfortunately I haven't been to Austria since I am doing AP. I'd definitely appreciate the dark skies now...

Looking forward to your next images, Freddy! Maybe the seahorse ;)

Regards
Stefan
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