Re: M1 Crab nebula from Chile

Benoit Schillings

cool. thank you for the info Roland. as usual, would also be so cool to have the fits/raw to play with.

-- benoit

On Fri, Dec 2, 2016 at 8:16 PM, chris1011@... [ap-gto] <ap-gto@...> wrote:

There is no coma in this image since it's a crop of a much wider field which also has no coma. The complete wide field image has round stars to the corners.
I did not process this image, that was done by Dave Jurasevich. Keep in mind you are looking at a compressed Jpeg image. The image was also not taken straight up, rather the object was close to the horizon, so the seeing was less than optimum.


-----Original Message-----
From: Benoit Schillings benoit.schillings@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Fri, Dec 2, 2016 9:20 pm
Subject: Re: [ap-gto] M1 Crab nebula from Chile

nice image. is there a hint of coma in the corners (bottom right) ? or will the system cover a wider field? Would be great to see a raw version showing the fainter extensions. Did you deconvolve the image ?

-- benoit

On Fri, Dec 2, 2016 at 5:36 PM, chris1011@... [ap-gto] <ap-gto@...> wrote:
Hi Philip,

Very well done.
I placed your image over Dave's with the stars registered. It is interesting to switch back and forth (blinking the images) because it shows a definite expansion of the nebular portions over the 7 years between your images.


-----Original Message-----
From: Philip Perkins ppml5@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Fri, Dec 2, 2016 4:31 pm
Subject: Re: [ap-gto] M1 Crab nebula from Chile

Very well done, and interesting to see details
revealed by the colour assignments. For
comparison here is a natural light RGB version
taken in 2009 using the RCOS 12.5" mounted on an AP900 GTO:

No meridian flip needed with this one either,
thanks to the AP mount! (Star processing is
cr*p - focus was entirely on the nebula)

At 17:59 02/12/2016, you wrote:

>Here's another fine image from Chile processed by Dave Jurasevich:
>This image of the crab nebula was taken from
>below the equator down in Chile at our remote
>site at Las Campanas with the AP 12" F8
>Astrograph. It’s a Ha/OIII composition
>assigning Ha to the red channel, OIII to the
>blue channel, and synthesizing the green channel
>with a combination of the two. Exposure time Ha
>23 x 1200 sec, OIII 25 x 1200 sec for a total exposure time of 16 hours.
>M1 is a far north object that does not rise very
>high in the sky in Chile, and this image shows
>just how pristine the skies are in the Chilean
>Andes mountains even for objects that are near
>the horizon. Image capture by Howard Hedlund of
>AP, image processing by Dave Jurasevich.

Philip Perkins
Wiltshire UK & Luberon France

Posted by: Philip Perkins <ppml5@...>

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