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Old 29-01-2021, 07:30 PM
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gregbradley
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NGC2030 widefield

This first light for a QHY294m camera. The camera is micro 4/3rds size with 4.63 micron pixels in 11mp mode. It can also shoot in 47mp mode and the pixels are 2.3 microns. In the 11mp mode the 4.63 micron pixel has a subset of 4 smaller pixels that are binned. The result is 92% QE and low read noise.

47mp mode would be good for widefield images or using camera lenses like a Samyang 135 F2 which I have.

I've paired with my AP RHA 305mm F3.8 scope intending it to image narrower field objects, galaxies, small nebulas.

This is really the 2nd light. The first light turned out OK but was really just a test.

NGC2030 imaged the same time as Marcus. Its one of my favourite LMC nebulas. For some reason the SkyX refers to this nebula as the Seagull Nebula which really is a different nebula. I don't know why it does.

6:37 hours, Ha O111 rgb image. All 300 seconds, gain 1750 offset 30. No flats (there was no vignetting and everything was clean) and bias just darks. Amp glow was minor and it calibrates out nicely. UNity gain is Gain 1600 and a recommendation of offset 25 which I'll switch to on future images but I don't think it would look any different.

https://pbase.com/gregbradley/image/171353128/large

Taken at my home observatory. I don't get very good seeing looking south like that.

Greg.
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Last edited by gregbradley; 30-01-2021 at 02:47 PM.
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  #2  
Old 29-01-2021, 08:22 PM
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petershah (Peter Shah)
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Stunning Colour and Detail....A great test shot
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Old 29-01-2021, 08:55 PM
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Humm...sorry....if you refer to the epic Marcus "benchmark"...something not quite right here.

The colour is great and signal is booming in...but the focus/resolution is soft and there is no subtle brightness variation.

Like the well-depth has been filled... and then some ...the result looks flat.
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Old 29-01-2021, 10:00 PM
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Quote:
Originally Posted by petershah View Post
Stunning Colour and Detail....A great test shot
Thank Peter.

Quote:
Originally Posted by Peter Ward View Post
Humm...sorry....if you refer to the epic Marcus "benchmark"...something not quite right here.

The colour is great and signal is booming in...but the focus/resolution is soft and there is no subtle brightness variation.

Like the well-depth has been filled... and then some ...the result looks flat.
I reverted to an earlier version. Probably pushed it too hard.
Seeing is soft to the south at my location hence the slightly soft look.

Greg.
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Old 30-01-2021, 08:19 AM
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marc4darkskies (Marcus)
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I didn't see your first version but this one looks very good Greg! The OIII is coming through reasonably well but the Ha areas seem a little pale
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Old 30-01-2021, 08:23 AM
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A few of my thoughts that are worth nothing Greg.

Detail good.

Composition not bad....could be better.

A bad sub in there from what I'm seeing.

I don't think the colour's great but not bad.....a sign of frustrated blending to me.

Doesn't look smooth to me.....more signal needed in the background.

Dynamic range not quite right and I think Peter's brightness across the field comment is correct but I just wouldn't call It quite flat.

Hey like I said Greg my thoughts are worth nothing.

Good effort I just expect great shots from you
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  #7  
Old 30-01-2021, 02:55 PM
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Quote:
Originally Posted by marc4darkskies View Post
I didn't see your first version but this one looks very good Greg! The OIII is coming through reasonably well but the Ha areas seem a little pale
Yeah that's true. I have redone it again this morning. I also used a bit of PixInsight for HDR multiscale transform which helps retain detail in the bright areas.

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Originally Posted by atalas View Post
A few of my thoughts that are worth nothing Greg.

Detail good.

Composition not bad....could be better.

A bad sub in there from what I'm seeing.

I don't think the colour's great but not bad.....a sign of frustrated blending to me.

Doesn't look smooth to me.....more signal needed in the background.

Dynamic range not quite right and I think Peter's brightness across the field comment is correct but I just wouldn't call It quite flat.

Hey like I said Greg my thoughts are worth nothing.

Good effort I just expect great shots from you
Thanks Louie. Quite right. I was a little annoyed with the compensation as it really needed to go up a tad to get that round donut neb fully in the scene. Oh well.

I took the comments on board and spent some time redoing it practically from scratch (same link) with particular attention to retaining detail in the bright O111 area in the birdlike nebula.

The O111 subs had larger stars. My camera adapter is a tad thick and the other night when it was hot I discovered I ran out of rack in room on the focuser. So I have adjusted the adapter on the camera to get a tiny amount of rack in so I suspect it did not rack in using temperature compensation plus blue tends to bloat anyway.

I used a star mask to block out the blue O111 stars as they were damaging the stars anyway.

I am happy with this version and it was a good run on a new camera. The camera overall seems quite good. Its touted as the replacement for the ASI 1600. It also has a 47mp mode which I'll experiment with on a night of good seeing. I already know the RHA will handle it on a night of good seeing as I used an ASI183 with the same sized 2.3 micron pixels before.

Haven't done an image for a while and relearnt the level of care required to get a good image.

https://pbase.com/gregbradley/image/171353128/large

Greg.
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Old 30-01-2021, 04:07 PM
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Like the repro very much. Chalk and cheese. Top shot.
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  #9  
Old 30-01-2021, 04:10 PM
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An order of magnitude improvement Greg!! Well done!
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Old 30-01-2021, 05:09 PM
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Quote:
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Like the repro very much. Chalk and cheese. Top shot.
Cheers Marc. I am a little rusty!

Quote:
Originally Posted by marc4darkskies View Post
An order of magnitude improvement Greg!! Well done!
Cheers Marcus. It was never going to be as good as yours but I did leave a fair bit on the cutting room table. Its also getting to know this new camera although its not that different to the ASI183M I had before. Wider field, a bit more QE but lower noise. It may be more sensitive in narrowband as well.

I wonder if I should crop it more. I really should have moved the camera up a bit more to get that bottom donut in the frame and take some of the space away from above the bubbled neb.

Greg.

Last edited by gregbradley; 30-01-2021 at 05:58 PM.
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  #11  
Old 30-01-2021, 09:29 PM
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It’s a fascinating area to image Greg, the final version here has been well worth the visit.
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  #12  
Old 30-01-2021, 11:01 PM
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Originally Posted by Ryderscope View Post
It’s a fascinating area to image Greg, the final version here has been well worth the visit.
Thanks Rodney, I appreciate your comments.

Greg.
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