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A big Apple for Christmas - M27 with T300 - Short exposures

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#1 XS_Man

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Posted 24 December 2017 - 08:37 AM

Hi all,smile.gif

 

A well-known deepsky target, M27, for Christmas day !

 

The captures are in fact earlier, last August 2017. 3 nights (...part of nights,
I remember that the clouds have shortened 2 of the 3).

 

Here I use my Orion Optics 300 mm F/D 5.3 with QHY5III 290 M for luminance
layer and a QHY5III 178 C for color layer. And as for my previous images, I use
short exposures technique (0.4 to 5 seconds) and manual sort out to have the
better possible result.

 

2 nights for luminance (26/08/2017 and 28_29/08/2017) plus half a night for color
27_27/08/2017). First night was good at the beginning but the 2 other nights were
only medium and reduced the resolution of the global image. It's a pity !

 

My final image :

http://www.webastro....-1514133635.jpg

 

As a comparison, here is the reference image from Adam Block with a much bigger
telescope, 500 mm :

http://www.caelumobs...om/obs/m27.html
http://www.caelumobs.../m27metcalf.jpg

 

From the detectivity point of view (faintest stars) Adam's image is better.
From the resolution point of view, the 2 image are very close, Adam's image
is only a little bit better.  

 

SETUP :
---------
Newton Orion Optics 300 mm F/D 5.3, on EQ-6 Mount

 

Luminance layer:
------------------
QHYCCD QHY 174 M (cooled) no filter.
13915 x 0.4 second. Gain = 48.
(10159+10989) x 0.4 second. Gain = 45.
5601 x 1 second. Gain = 45.
Darks.

 

Color layer :
-----------------
QHYCCD QHY5III 178 C (uncooled) + Ir/UV cut.
934 x 5 seconds. Gain = 40.
Darks.

 

Manual sort out of RAW image.
Registration with DeepSkyStacker.
Post-processing with Iris + Photoshop.

 

Albéric


Edited by XS_Man, 24 December 2017 - 11:43 AM.

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#2 XS_Man

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Posted 26 December 2017 - 01:14 PM

I've added a new version, more saturated and with a harder processing  for center of nebula :

 

http://www.webastro....-1514311373.jpg

 

Albéric


Edited by XS_Man, 26 December 2017 - 01:15 PM.

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#3 astromomo

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Posted 30 December 2017 - 06:00 PM

Hi albéric,

 

Stunning result. You are one of the masters in short exposure DSO.

 

I just restarted DSO imaging this year using this technique, i already made it better than with my atik 383 ccd camera...

 

Moïse


Edited by astromomo, 30 December 2017 - 06:01 PM.


#4 bratislav

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Posted 30 December 2017 - 10:00 PM

Fantastic result, considering the site and telescope size. Lucky deep sky imaging really has a bright future!

For a comparison with yet another (much larger) telescope at a professional site where subarcsecond seeing is often possible, here's my shot of M27.

Scope was 1.4m f/8, and because filters professionals use (UBVRI) are somewhat different from "our" RGB palette, colors are different yet again.

But resolution is there if you want to compare!

(that particular night my red images FWHM were around 0.7 arcsec)

 

 

Attached Thumbnails

  • M27-BVR.jpg

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#5 XS_Man

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Posted 18 January 2018 - 05:07 PM

Hi Bratislav ! smile.gif

 

Many thanks for your comment !

 

Fantastic result, considering the site and telescope size. Lucky deep sky imaging really has a bright future!

For a comparison with yet another (much larger) telescope at a professional site where subarcsecond seeing is often possible, here's my shot of M27.

Scope was 1.4m f/8, and because filters professionals use (UBVRI) are somewhat different from "our" RGB palette, colors are different yet again.

But resolution is there if you want to compare!

(that particular night my red images FWHM were around 0.7 arcsec)

That's a very nice image from a big professionnal telescope even if the color palette is strange for my "RVB eyes".

I've compared : resolution is the same as Adam's reference picture (with a 500 mm telescope).

Without adaptative optics system, it's a great result !

 

My picture is a little less sharp. "My observatory" is an average plain spot in France. Average seeing conditions are

far away from a spot like french Pic du Midi observatory !  And only short exposure technique could counterweight

these very medium seeing conditions !

 

Here is my picture with a "weight" reduce to less to 500 ko :

 

1359-1516311967.jpg


Edited by XS_Man, 18 January 2018 - 05:09 PM.

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#6 XS_Man

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Posted 19 January 2018 - 07:50 AM

Hi albéric,

 

Stunning result. You are one of the masters in short exposure DSO.

 

I just restarted DSO imaging this year using this technique, i already made it better than with my atik 383 ccd camera...

 

Moïse

Thanks very much Moïse !

 

Hope that you will post your own images on the forum  !

 

Albéric



#7 exaxe

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Posted 19 January 2018 - 10:31 AM

She is beautiful this apple!
Bravo Alberic




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