Abell 2256 cluster + use of SharpCap annotations

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Menno555
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Abell 2256 cluster + use of SharpCap annotations

#1

Post by Menno555 »

For my Meade LX200 8" f/10 scope, I have the Optec Lepus Standard 0.62x reducer. But I don't use that a lot, so time to experiment it some more.
For that I choose the Abell 2256 cluster in Ursa Minor. It's a cluster that's captured very, very rarely.

Abell 2256 has around 500 galaxies in it and is at around 800 million lightyears. It was thought to be just another galaxy cluster, yet studies with radio telescopes show a different story.
Like the studies with the LOFAR (Low Frequency Array) shows that Abell 2256 most likely is formed out of collisions and mergers of smaller clusters. This leaves a kind of radio signature like the one that can be seen here: https://aasnova.org/2022/05/02/featured ... bell-2256/
I couldn't capture really deep due to the fact that nights here at the moment are not really dark. Still a nice result.

I also made a negative, b/w version with annotations. For this I used the annotation feature of Sharpcap. This shows galaxies up to MAG18 but I checked in Aladin with the NED catalogue and the faintest one showing is MAG21.3.
I platesolved a single sub and used the annotation feature. I then dialed the Display Histogram totally down, leaving only the annotations and some stars. This I saved as image and used in Photoshop as layer with Screen. Since all but the annotations was black, it acted as a nice transparent layer :)
Altered the overal color from orange to blue for better viewing.

The 3000x2044px color version can be seen here: https://i.ibb.co/ZY0MNDP/Abell2256-RGB.jpg
The negative, b/w annotation 4048x2758px version here: https://i.ibb.co/NNNBQ9R/Abell2256-bw-ann.jpg

Image

Image

Bortle 6/7
Meade LX200 8" f/10 ACF OTA
Ioptron CEM25EC mount (no guiding)
Baader IR/UV Cut filter
Zwo ASI071MC Pro camera

Captured with SharpCap Pro @ -10 Celsius / White balance R50 B50
22 x 180sec / Gain 90 / Offset 4
26 x 300sec / Gain 90 / Offset 4
20 x darks, 50 x flats and 50 x darkflats per set

Stacked with SiriL and Sirilic

Processed with Siril and Photoshop
Siril: Crop, Photometric Color Calibration, Background Extraction, Histogram
Photoshop: Camera Raw Filter (white balance, lights, contrast, color saturation, clarity, vignette), noise reduction with NoiseXterminator plug-in.
timh
Posts: 515
Joined: Mon Aug 26, 2019 5:50 pm

Re: Abell 2256 cluster + use of SharpCap annotations

#2

Post by timh »

Doing the negative and then fading back the histogram is a good way of doing annotation. I generally do it in PI on a positive image but it ends up looking too busy for things like galaxy fields - so that is a good approach

Tim
RMSQueenMary
Posts: 68
Joined: Mon Jan 15, 2018 4:58 am

Re: Abell 2256 cluster + use of SharpCap annotations

#3

Post by RMSQueenMary »

Nice image! 8-)

I like seeing distant galaxy clusters imaged. They are often my favorite objects to look at through EAA. 8-)
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Menno555
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Joined: Mon Apr 20, 2020 2:19 pm
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Re: Abell 2256 cluster + use of SharpCap annotations

#4

Post by Menno555 »

timh wrote: Mon Jun 27, 2022 10:08 am Doing the negative and then fading back the histogram is a good way of doing annotation. I generally do it in PI on a positive image but it ends up looking too busy for things like galaxy fields - so that is a good approach

Tim
That was indeed the reason for going negative, it became too busy. Also the orange added to that, the blue on white gives a more "readable" effect :)
RMSQueenMary wrote: Thu Jun 30, 2022 11:27 pm Nice image! 8-)

I like seeing distant galaxy clusters imaged. They are often my favorite objects to look at through EAA. 8-)
Thanks!
For me it's in a way more impressive to see/capture this than M101 for example. M101 is grand and detailed ... but it's just 1 galaxy. And in clusters like these are hundreds of M101 (in a matter of speaking).

Menno
RMSQueenMary
Posts: 68
Joined: Mon Jan 15, 2018 4:58 am

Re: Abell 2256 cluster + use of SharpCap annotations

#5

Post by RMSQueenMary »

Menno555 wrote: Fri Jul 01, 2022 12:25 pm
timh wrote: Mon Jun 27, 2022 10:08 am Doing the negative and then fading back the histogram is a good way of doing annotation. I generally do it in PI on a positive image but it ends up looking too busy for things like galaxy fields - so that is a good approach

Tim
That was indeed the reason for going negative, it became too busy. Also the orange added to that, the blue on white gives a more "readable" effect :)
RMSQueenMary wrote: Thu Jun 30, 2022 11:27 pm Nice image! 8-)

I like seeing distant galaxy clusters imaged. They are often my favorite objects to look at through EAA. 8-)
Thanks!
For me it's in a way more impressive to see/capture this than M101 for example. M101 is grand and detailed ... but it's just 1 galaxy. And in clusters like these are hundreds of M101 (in a matter of speaking).

Menno
I like seeing distant galaxy clusters. It makes you think about if there is life out there. That is the beauty right there. 8-) :D

Individual galaxies are beautiful and people are more likely to enjoy seeing them. 8-)

I prefer galaxy clusters because the beauty is in how insignificant we are. 8-) :lol:
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