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Old 14-06-2017, 12:16 PM
Placidus (Mike and Trish)
Narrowing the band

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Omega Centauri with a few annotated stars

Omega just about overflows our field of view, so here be a 9 panel mosaic.

The full size image (7000 pixels/side) is about 6 MB.

A smaller version is here.

The thumbnail is a tight crop of a representative patch.

We've had two goals here. An easy one is to make the cluster stand out from the background, high contrast and sharp (without overdoing the sharpening), so we've gone easy on stretching. The background is stretched about 200 times compared with a raw sub.

The second goal was to show the colour how we think it should be. We are motivated by NASA's Hubble close-up, where they show the majority of stars in the cluster as yellow-white.

As mentioned elsewhere, we're very aware that this is a fairly old, seniors-card carrying, zimmer-frame pushing member of our galaxy. Consequently most of the stars are older than the sun. When we look at it visually, it is a warm colour, certainly not blue-white.

We've annotated the spectral types of a few of the brighter stars, and, keeping in mind that anything in Centaurus is reddened by dust (see NGC 4945 for example), and we want it to stay that way, we've made the G0 star close in at about 8 o'clock be a yellow-white. The smattering of A0 and A5 stars scattered about the image are by comparison very blue-white.

A close look at the core shows that as well as the overwhelming orange-yellow stars, there is a heavy sprinkling of blue stragglers.

There is an edge-on spiral toward the top left corner, but not much else in the way of galaxies, as befits the somewhat dusty location.

North is up. The field is about 1.08 degrees across, at 0.55 sec arc/pixel.

72 ten minute subs (12 hours total). Aspen CG16M on 20" PlaneWave. Taken mostly under full moon. Processing with GoodLook 64.

Very best,
Mike and Trish
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Last edited by Placidus; 14-06-2017 at 12:50 PM.
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  #2  
Old 14-06-2017, 12:33 PM
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multiweb (Marc)
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Superb resolution Mike. Very cool fov.
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Old 14-06-2017, 12:36 PM
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Atmos (Colin)
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A resounding in every respect Mike & Trish. Definitely need to see this on the big screen; not iPhone!
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Old 14-06-2017, 01:09 PM
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strongmanmike (Michael)
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Well...who would'a thunk it possible to make another image of Omega Centauri so... un-boring

Lovely processing with no obvious artefacts and completely concur with your colour reasoning and also like your signature slightly soft processing, lends a sense of believability to the cluster, nice job indeed guys

9 panel mosaic of Omega Cen huh?..did that introduce any registration difficulties?

Mike
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Old 14-06-2017, 02:02 PM
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SimmoW (SIMON)
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Not much else to say!
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Old 14-06-2017, 02:06 PM
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RickS (Rick)
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Very nice, M&T, tight little stars and colour not a million miles away from the PhotometricColorCalibration results

Cheers,
Rick.
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  #7  
Old 14-06-2017, 02:08 PM
Placidus (Mike and Trish)
Narrowing the band

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Quote:
Originally Posted by multiweb View Post
Superb resolution Mike. Very cool fov.
Thanks muchly, Marc. We seem to remember that you had a lot to do with making the observatory possible!

Quote:
Originally Posted by Atmos View Post
A resounding in every respect Mike & Trish. Definitely need to see this on the big screen; not iPhone!
Cheers, Colin!

Quote:
Originally Posted by strongmanmike View Post
Well...who would'a thunk it possible to make another image of Omega Centauri so... un-boring

Lovely processing with no obvious artefacts and completely concur with your colour reasoning and also like your signature slightly soft processing, lends a sense of believability to the cluster, nice job indeed guys

9 panel mosaic of Omega Cen huh?..did that introduce any registration difficulties?

Mike
Thanks mightily, Mike. After one night only, when we just had the four corner images, registration was tricky because of hideous disparities between the subs taken under moonlight and those before moon-rise. On the second night, we did the corners in the opposite order, and added the four intermediate sides. That made it all go together painlessly with no fiddling about.

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Not much else to say!
Wow. Thanks, Simmo. 160 fingers and 160 toes. That's more than there are stars in the image!
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Old 14-06-2017, 04:15 PM
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Andy01 (Andy)
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That's fabulous guys
Lovely resolution and colour at 50% but does it get a tad softish at 100%?
(maybe I'm not used to seeing such a hi res result)

I just compared to Marc's & Ricks recent wonderful versions and boy oh boy, the resolution you have there is truly remarkable.
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Old 14-06-2017, 04:29 PM
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PRejto (Peter)
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Wow! What an amazing photo. Just wonderful. Love the colour which seems entirely natural and unforced.

Peter
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Old 14-06-2017, 05:44 PM
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Hi Mike & Trish,
that could be the highest resolution image ever posted here of that target.
Top picture.

cheers
Allan

Last edited by alpal; 14-06-2017 at 06:47 PM.
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Old 14-06-2017, 06:06 PM
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Peter Ward
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Rather epic and very sublime imagery.

Like this one very much.
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  #12  
Old 14-06-2017, 07:14 PM
Placidus (Mike and Trish)
Narrowing the band

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Quote:
Originally Posted by Andy01 View Post
That's fabulous guys
Lovely resolution and colour at 50% but does it get a tad softish at 100%?
(maybe I'm not used to seeing such a hi res result)

I just compared to Marc's & Ricks recent wonderful versions and boy oh boy, the resolution you have there is truly remarkable.
Thanks, Andy. The scope is oversampled relative to the seeing. There may be something to be said for reducing the image to perhaps 70%. More than that loses genuine detail.

Quote:
Originally Posted by PRejto View Post
Wow! What an amazing photo. Just wonderful. Love the colour which seems entirely natural and unforced.

Peter
Thanks, Peter!

Quote:
Originally Posted by alpal View Post
High Mike & Trish,
that could be the highest resolution image ever posted here.
Top picture.

cheers
Allan
HI, Allan! We are delighted that you like it.

Quote:
Originally Posted by Peter Ward View Post
Rather epic and very sublime imagery.

Like this one very much.
Thanks so much, Peter. That is extremely encouraging.

Best to all,
M & T
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Old 14-06-2017, 07:19 PM
DJT (David)
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Wow, resolution is seriously good and the colours make sense as per earlier comments and per your interesting write up.

Would never have considered you would need to do a mosaic to do this, what a challenge and what a great result .
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Old 15-06-2017, 08:30 AM
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Very nice. Great image!
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  #15  
Old 15-06-2017, 10:21 AM
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Retrograde (Pete)
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This is simply amazing - such exquisite detail and scale
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Old 15-06-2017, 11:32 AM
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Brilliant, such detail, great colour.... looks as i imagine it should.
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Old 15-06-2017, 12:11 PM
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Nice shot of a perennial target Mike. The resolution is very nice and I think the 10 minute subs have made a huge difference in that regard. Nice saturation too.
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  #18  
Old 15-06-2017, 02:32 PM
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marc4darkskies (Marcus)
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Globs are boring! .... Except THIS ONE!!! Way to go M&T! Beautifully done!
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  #19  
Old 15-06-2017, 04:17 PM
Placidus (Mike and Trish)
Narrowing the band

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Quote:
Originally Posted by DJT View Post
Wow, resolution is seriously good and the colours make sense as per earlier comments and per your interesting write up.

Would never have considered you would need to do a mosaic to do this, what a challenge and what a great result .
Thanks David. Glad the story holds together.

Quote:
Originally Posted by Bart View Post
Very nice. Great image!
Cheers, Bart!

Quote:
Originally Posted by Retrograde View Post
This is simply amazing - such exquisite detail and scale
Thanks muchly, Pete.

Quote:
Originally Posted by vlazg View Post
Brilliant, such detail, great colour.... looks as i imagine it should.
Hi, George. Thanks for the encouragement.

Quote:
Originally Posted by Paul Haese View Post
Nice shot of a perennial target Mike. The resolution is very nice and I think the 10 minute subs have made a huge difference in that regard. Nice saturation too.
Thanks Paul. We might have to think about how on other targets to use short subs for the brightest bits and combine them sensibly with longer subs for the very faintest stuff.

Quote:
Originally Posted by marc4darkskies View Post
Globs are boring! .... Except THIS ONE!!! Way to go M&T! Beautifully done!
Yippee! Thanks Marcus!
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  #20  
Old 15-06-2017, 05:27 PM
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RickS (Rick)
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Very nice, M&T, tight little stars and colour not a million miles away from the PhotometricColorCalibration results

Cheers,
Rick.
Hey, I commented too M&T, but mine got lost due to a race condition
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