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Just for fun


Howard Dutton
 

Can't believe I had clear skies last night, it was supposed to be "mostly cloudy".  After messing around with culmination for way too many HOURS I took two images with the 10"F4 OnStep'ized G11.

M1 below is LRGB of 5x 1 minute exposures on each channel, unguided:




The left side still isn't right... is that focuser tilt?


Khalid Baheyeldin
 

Wow. What an image ... great shot ...

I am not the one to judge the focus. I feel something is a tad off, but can't pin point it.
Perhaps there is more orange on the upper edge of the stars than on the bottom edge?

What I also noticed is that when I zoom in, there are these faint wiggly things all over the image, like gummy worms or something. Would that be an artifact of post-processing?


Charles
 

Hi Howard,
I would say it s a collimation issue and you have to perform an auto focus when you change the filter. 
Charles
 
Gesendet: Sonntag, 06. Januar 2019 um 16:29 Uhr
Von: "Howard Dutton" <hjd1964@...>
An: onstep@groups.io
Betreff: [onstep] Just for fun
Can't believe I had clear skies last night, it was supposed to be "mostly cloudy".  After messing around with culmination for way too many HOURS I took two images with the 10"F4 OnStep'ized G11.

M1 below is LRGB of 5x 1 minute exposures on each channel, unguided:




The left side still isn't right... is that focuser tilt?


tnut55
 

10 f/4...coma corrector?  To me it looks like scope collimation my be a tad off center or perhaps focuser tilt.


On Sun, Jan 6, 2019 at 9:38 AM, Khalid Baheyeldin
<kbahey@...> wrote:
Wow. What an image ... great shot ...

I am not the one to judge the focus. I feel something is a tad off, but can't pin point it.
Perhaps there is more orange on the upper edge of the stars than on the bottom edge?

What I also noticed is that when I zoom in, there are these faint wiggly things all over the image, like gummy worms or something. Would that be an artifact of post-processing?


ckampf
 

Looks like there is still some coma on the left side.
Maybe a tilted corrector. 



Von meinem Samsung Galaxy Smartphone gesendet.

-------- Ursprüngliche Nachricht --------
Von: Howard Dutton <hjd1964@...>
Datum: 06.01.19 19:29 (GMT+04:00)
An: onstep@groups.io
Betreff: [onstep] Just for fun

Can't believe I had clear skies last night, it was supposed to be "mostly cloudy".  After messing around with culmination for way too many HOURS I took two images with the 10"F4 OnStep'ized G11.

M1 below is LRGB of 5x 1 minute exposures on each channel, unguided:




The left side still isn't right... is that focuser tilt?


ckampf
 

Guess these "worms" are dead or hot pixels. 



Von meinem Samsung Galaxy Smartphone gesendet.

-------- Ursprüngliche Nachricht --------
Von: Khalid Baheyeldin <kbahey@...>
Datum: 06.01.19 19:38 (GMT+04:00)
An: onstep@groups.io
Betreff: Re: [onstep] Just for fun

Wow. What an image ... great shot ...

I am not the one to judge the focus. I feel something is a tad off, but can't pin point it.
Perhaps there is more orange on the upper edge of the stars than on the bottom edge?

What I also noticed is that when I zoom in, there are these faint wiggly things all over the image, like gummy worms or something. Would that be an artifact of post-processing?


Howard Dutton
 
Edited

On Sun, Jan 6, 2019 at 09:06 AM, ckampf wrote:
Looks like there is still some coma on the left side.
Maybe a tilted corrector. 
Perhaps the camera/MPCC tilted in the focuser.  I have an aluminum shim inside to "gently" wedge the CC unit in the focuser.  It seems very sturdy but the tolerances at F4 are unforgiving.

My image of the Horsehead Nebula taken immediately after M1 (on the other side of the meridian) seems to have tighter stars across the field.  This one was autoguided 5x 120s RGB, no L since clouds rolled in right after I finished the last RGB frame (I was going to do 5x 240s of L.)  I used the ancient AutostarIP application for stacking these.  It has an option to filter out hot pixels.  I also worked in Photoshop with curves to bring forward more detail.  By the way, the camera is a ZWO ASI178MM-Cool. This one is probably worth keeping...