Author Topic: Image prerelease: M51  (Read 7822 times)

Offline vicent_peris

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Image prerelease: M51
« on: 2010 June 05 04:16:19 »
Hi all,

we have been working at Calar Alto during the last month on Messier 51. The image is being presented very soon, but I decided to make a prerelease here at home. :-)

This is a HaRGB composite made with the 1.23 meter scope and with our new Baader Planetarium filters. RGB exposures amount a total of 24 hour integration time; H-alpha has a total of 11 hours.

Here is the image at 600 pixel wide resolution:



You can see further information, as well as full resolution image, at this link:

http://astrofoto.es/Galeria/2010/M51/M51_CAHA_en.html

We have found a large structure going awas from NGC5195 that is not mentioned in any scientific paper. Take a look to the H-alpha image to see clearly the large arc to the right side of the image:



As I was saying in the other M51 thread, the calculated limiting magnitude of this image is about g'=26.

Acquisition was made by Jack Harvey and me; processing by Jack Harvey, Steve Mazlin and me.

Very soon I will write some technical aspects about this image.


Best regards,
Vicent.

Offline Harry page

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Re: Image prerelease: M51
« Reply #1 on: 2010 June 05 06:24:41 »
Hi

That's a amazing image  :D

A question for you I have some M51 Ha I have tried mixing with my rgb , do you process them separately and mix it add the end or do you add your Ha at the linear stage  ???


Harry
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Offline Jack Harvey

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Re: Image prerelease: M51
« Reply #2 on: 2010 June 05 06:58:16 »
As you well know Harry there are multiple ways to skin a cat.  I am not sure how Vicent did the final version but my version of this was done by taking the R and Ha master frames (while linear) and using Pixel Math to make a combine (70% Ha and 30% R).  I then used the resultant HaR frame in the red slot of the LRGB combine.  Vicent came up with a new way to process the Ha and will publish it in the future, is my understanding.  His version did a much better job of emphasizing the Ha contribution to the final image, and is what you see in this post.
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Offline sleshin

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Re: Image prerelease: M51
« Reply #3 on: 2010 June 05 08:28:43 »
Another Wow image from Vicent, Jack, and Steve. Jack, did you also use the HaR combined frame for the L channel?

Steve
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Offline vicent_peris

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Re: Image prerelease: M51
« Reply #4 on: 2010 June 05 08:47:32 »
Hi,

I did the HaR combination in the linear stage. But first it's necessary to process the H-alpha image:

- We must substract the continuum from the H-alpha image. Even in at 7 nm filter there's a lot of continuum contamination. This is a 4 hour H-alfa calibrated image: http://pteam.pixinsight.com/ha1.jpg. And this is the continuum cleaned H-alpha image: http://pteam.pixinsight.com/ha2.jpg. This cleaning is done with a simple PixelMath formula. I will speak about this in the near future.

- We must denoise the H-alpha image because we are going to amplify the H-alpha signal. But, of course, we don't want to contaminate our deep R channel with noise from the H-alpha one.

We first make an RGB composite and do the appropiate color calibration. With the color calibrated color image, we can insert the H-alpha channel information. The H-alpha image wil be multiplied by a factor >1 to make the H-alpha enhancement. So, if we want to we insert the H-alpha image to the R channel of a color image with a x4 emission enhancement, the R formula will be: $T+(ha-Med(ha))*4 . The formula for G and B channels will be simply $T.


Best regards,
Vicent.

Offline Harry page

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Re: Image prerelease: M51
« Reply #5 on: 2010 June 05 09:15:26 »
Hi Vincent

This is very interesting as my Ha from my M51 looks like your first image ( Ok a poor copy  ;D) and when I use this it washes out my image


So tell me more  :D

Harry
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Offline Harry page

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Re: Image prerelease: M51
« Reply #6 on: 2010 June 05 11:05:36 »
Hi Again

Sorry just read your pixel maths ;)  what does $T stand for


Harry
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Offline vicent_peris

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Re: Image prerelease: M51
« Reply #7 on: 2010 June 05 11:19:23 »
Hi Again

Sorry just read your pixel maths ;)  what does $T stand for


Harry

The target image of PixelMath: the image you are applying the PixelMath on.



v.

Offline mmirot

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Re: Image prerelease: M51
« Reply #8 on: 2010 June 05 17:21:05 »
Nice work V.

Are you going to Chicago?

Max

Offline Harry page

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Re: Image prerelease: M51
« Reply #9 on: 2010 June 10 10:16:55 »
Hi

Any more info on this image as I am really interested in how you did it  :D

Harry
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Offline Yuriy Toropin

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Re: Image prerelease: M51
« Reply #10 on: 2010 June 11 02:37:13 »
Congratulation to all co-authors of this M51 project published by APOD! :)

http://antwrp.gsfc.nasa.gov/apod/ap100611.html

Offline xatamec

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Re: Image prerelease: M51
« Reply #11 on: 2010 June 12 14:49:39 »
Congrats to all the team por this fantastic image and the APOD reward!  ;)

Sergi

Offline twade

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Re: Image prerelease: M51
« Reply #12 on: 2010 June 13 22:54:46 »
All I can say is WOW!!!

Wade

Offline Jack Harvey

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Re: Image prerelease: M51
« Reply #13 on: 2010 July 22 18:22:14 »
The image of M51 was selected by CERN's International Journal of High Energy Physics as Picture of the Month
http://cerncourier.com/cws/article/cern/43191
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Offline georg.viehoever

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Re: Image prerelease: M51
« Reply #14 on: 2010 July 27 10:47:00 »
Your M51 is the pin-up poster of the August 2010 "Sterne und Weltraum" magazine (one of the two major astronomy magazines in Germany), see http://www.astronomie-heute.de/artikel/1039179 .

Congratulations!

Georg
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