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Eye of God

Astrophotography
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#1 ClownFish

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Posted 25 September 2021 - 08:44 PM

Here's my first real attempt at the Helix Nebula.

Celestron C11 EdgeHD f/7
ZWO ASI 1600MM Pro cooled to -10C
iOptron CEM120 EC2
KStars
Pixinsight

- Baader Ha (3.5NM) 120 3-minute exposures
- Baader OIII (4nm) 59 3-minute exposures

Unguided

 

Helix RGB-CN.jpg


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#2 pretyro

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Posted 25 September 2021 - 10:38 PM

   That is really nice. 

     I have not done any deep sky imaging.   So, what do you mean by "unguided"?  Does it mean that you found the nebula by hand via star hopping rather than letting the scope find it for you?



#3 ClownFish

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Posted 25 September 2021 - 11:31 PM

   So, what do you mean by "unguided"?  

In long exposure imaging, the mount tracks the sky, but most mounts need some help making sure the scope stays on target.  This is called guiding.  On the old days, users would monitor the tracking and put the scope back on track by hand.  Then auto guiders use a camera to do that chore.  The two biggest reasons a mount needs to be guided is that the polar alignment is off, or that the gears are not 100% perfect and wobble.  This leads to small errors in tracking called periodic error.  

 

The iOptron CEM120 EC2 mount has hi-resolution encoders that enable the mount to track extremely well.  The mount can detect minute errors in the gears such as the periodic error I mentioned above, and even gear skip (backlash) and correct for it.  This means that if the polar alignment is perfect, and there's no outside forces acting against the scope, mount, or pier, then auto-guiding is not needed.   My scope is inside an observatory, on a concrete pier that runs five feet underground.  It's solid.  And I use a program called EKOS to ensure my polar alignment stays perfect (well, within a few arc seconds).  So my tracking is dead on - all by itself.


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#4 Grimstod

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Posted 26 September 2021 - 06:48 AM

Great results especially unguided. Did you crop at all?



#5 ClownFish

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Posted 26 September 2021 - 07:01 AM

Great results especially unguided. Did you crop at all?

Thanks.  I trimmed off the edges a bit, about 5% maybe, from some misalignment between the various subs. 



#6 Mert

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Posted 26 September 2021 - 07:15 AM

Great image, and unguided!


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