Author Topic: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France  (Read 179 times)

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The Thing

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It was a bit of a misty sky but the streetlamps had gone off and it got nice and dark before the moon came up. Still I'm happy with this :) as first light for my new coma corrector. There has been no sharpening or noise reduction and collimation is a bit off bottom left.

50 x 120s @iso1600, unmatched darks (used 300s ones)
Telescope aperture and focal ratio:   Teleskop Service TS1506UNC 6" f4, TS KomakorrF4
Camera and filters used:   Canon1100D defiltered, Astronomik UV/IR Cut Clip Filter
Processing applied:   Pixinsight BatchPreprocessing, PhotometricColorCalibration, DynamicCrop, Arcsinh Stretch, CloneStamp, IrfanView Auto-adjust Colours.

« Last Edit: Oct 17, 2017, 11:43:04 by The Thing »
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Carole

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #1 on: Oct 16, 2017, 18:49:55 »
Wow Duncan, that's the best image you have done.  Lovely star colours, I don't know if you have done anything with your monitor yet, but the image is far too yellow, if the overall colour could be corrected it is definitely your best.

Carole

JohnP

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #2 on: Oct 16, 2017, 18:53:47 »
Yeah that does look 'bootiful' Duncan especially the full size - tons of detail & pin point stars. Agree with Carole though does look like colour is not quite correct. It's got that nice 'misty' look to it that Mark always seems to get on his pics - I guess a sign of good skies.

Really good - John

The Thing

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #3 on: Oct 16, 2017, 19:06:16 »
Well thank you both. It's finally all coming together.

My screen is now fully colour calibrated and looks excellent😀 but it's yellow on my phone😥. Maybe I've used the wrong colour temp target or something.
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MarkS

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #4 on: Oct 16, 2017, 20:50:27 »
Wow!

That is stunning.  You have achieved incredible depth and good detail.  There's even faint wispiness bridging the gap between M31 and M110.  You ought to be really pleased with that.

The colour is definitely seriously off - far too much yellow.

Mark

The Thing

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #5 on: Oct 16, 2017, 20:55:32 »
Wow!

That is stunning.  You have achieved incredible depth and good detail.  There's even faint wispiness bridging the gap between M31 and M110.  You ought to be really pleased with that.

The colour is definitely seriously off - far too much yellow.

Mark

Thanks Mark, I am amazed at what I got considering the milkyness of the sky and short exposures. I was trying to stop the galaxy core getting too blown out, I think shorter still and more subs would have been better.

I used the Photometric Color Calibration tool with the standard Average Spiral Galaxy preset so I would have thought the colour would be right. I have tried SNCR to remove a small amount of green and get a redder result, maybe that's better, who knows.
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MarkS

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #6 on: Oct 16, 2017, 21:40:38 »
Quote from: The Thing

Thanks Mark, I am amazed at what I got considering the milkyness of the sky and short exposures. I was trying to stop the galaxy core getting too blown out, I think shorter still and more subs would have been better.

I used the Photometric Color Calibration tool with the standard Average Spiral Galaxy preset so I would have thought the colour would be right. I have tried SNCR to remove a small amount of green and get a redder result, maybe that's better, who knows.

I've had mixed results from PCC.  I found my images came out noticeably green unless I used Bayer Drizzle during stacking.  Something weird happens to the distribution of colour in my stars during conventional stacking which doesn't happen when Bayer Drizzle is used:
https://pixinsight.com/forum/index.php?topic=11494

I haven't had a chance to look into it further - I've got too many things on the go at the moment!

On your JPG image I quickly applied a PixelMath expression $T,$T*0.85,$T for the R,G,B channels to reduce the green followed by a function degree 1 ABE and the result was pretty good.  So I reckon you are seeing the same PCC issue as me.

Mark
« Last Edit: Oct 16, 2017, 22:16:00 by MarkS »

MarkS

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #7 on: Oct 17, 2017, 06:30:19 »
Quote from: Apophis
and it seemed to be flipped bottom right to top left , is it to do with the scope or processing.?
Roger

It's just rotated 180 degrees. There's no top or bottom out there in space - images can be displayed any way round that the imager prefers!

Mark

Hugh

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Re: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #8 on: Oct 17, 2017, 09:12:20 »
Nice picture Duncan, such a beautiful object ~ and only 2.5 million light years away!

Interesting that, a bit like the Hubble 'Deep Field,' when I clicked on the image and then magnified around the two stars on the right of your picture (mid-way), you see some many more fainter stars in the background.

Thanks

Hugh

The Thing

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Re: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #9 on: Oct 17, 2017, 11:44:15 »
I've done some tweaking, corrected the colour, sharpened, de-pinked the bright stars and so on. Image is at the bottom replacing the original.
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Re: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #10 on: Oct 17, 2017, 16:02:11 »
Can you leave original on as well as I would like to see difference - thks,  John

The Thing

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Re: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #11 on: Oct 17, 2017, 16:58:15 »
Here's a link to the gallery page for the previous version.
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The Thing

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Re: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #12 on: Oct 17, 2017, 17:00:17 »
Nice image, i have got to tackle this.
On a technical point i saw M31 on a board ie
(img)
and it seemed to be flipped bottom right to top left , is it to do with the scope or processing.?
Roger

All depends how you have your camera on the scope, and you can always rotate it.
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The Thing

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Re: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #13 on: Oct 17, 2017, 17:03:12 »
I've found that GIMP 2.9.6 from the gimp.org development downloads section supports 32bit files. Been playing with noise reduction, sharpening and levels and have a really leery version with blue star forming regions and all sorts popping out. No red H-alpha blobs though.
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Mac

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Re: Modified: M31 Andromeda Galaxy 14 October 2017, Manche, France
« Reply #14 on: Oct 17, 2017, 17:28:23 »
Nice Image
Mac.
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