Orpington Astronomical Society

Astronomy => Astrophotography => Topic started by: MarkS on Aug 13, 2018, 06:25:07

Title: The Eagle Nebula M16
Post by: MarkS on Aug 13, 2018, 06:25:07
Here's another collimation experiment for my Celestron C11 with Starizona LF Corrector at f/7.2 but the result is good enough to post, at least the central portion of it is!

It's only 20 minutes of data with the modified Sony A7S.  40x30sec subs at ISO 10000.

(http://www.markshelley.co.uk/Astronomy/2018/eagle_20180804_small.jpg)

Larger version here:  http://www.markshelley.co.uk/Astronomy/2018/eagle_20180804.jpg

Mark
Title: Re: The Eagle Nebula M16
Post by: Carole on Aug 13, 2018, 10:02:52
Is the collimation problem the reason for the mis-alignment of the star colours which I have not seen in a DSLR before let alone one of your images?   

Nice FOV I remember your very first M16 done with this scope and your Canon 350D.

Carole
Title: Re: The Eagle Nebula M16
Post by: NoelC on Aug 13, 2018, 10:33:27
The scale and accuracy of the image is really good.
Well done - I hope you go back to it at some point.

Noel
Title: Re: The Eagle Nebula M16
Post by: MarkS on Aug 13, 2018, 19:25:28
Quote from: Carole
Is the collimation problem the reason for the mis-alignment of the star colours which I have not seen in a DSLR before let alone one of your images?   

Nice FOV I remember your very first M16 done with this scope and your Canon 350D.


No it's not collimation but atmospheric dispersion due to the Eagle being so low in the sky - top of the star is blue and the bottom is red.  I need to re-process to align the RGB  ;)

Here's that original image, taken 10 years ago:
http://www.markshelley.co.uk/Astronomy/2008/eagle2008.html

Mark