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#1 Timberwolf99

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Posted 14 October 2021 - 11:14 AM

I have been playing with planetary photography for about a year now.  I feel I am making progress up this steep learning curve but hit some walls occasionally.   The biggest problem I am concerned with now is focusing.  I have a Celestron Nexstar 8SE and the Celestron focuser motor.  I am using a Svbony SV305.  I capture using Sharpcap and then process with PIPP, AS3, Registax 6 and GIMP. I have not had any success using the focus tools in Sharpcap and usually end up focusing visually from my laptop.  I am looking for some feedback and tips to improve my results.  Please see the photos here and help if you can.  Thanks.

 

Bill

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#2 Borodog

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Posted 14 October 2021 - 11:23 AM

I have been having very good success lately with autofocusing using the Celestron Focus Motor and SharpCap. Can you describe exactly how you are proceeding and exactly what the trouble is that you've been having?


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#3 Timberwolf99

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Posted 15 October 2021 - 10:04 AM

Borodog, thanks for the reply.I have not tried "autofocusing".  I believe that might only be available in the pro version of Sharpcap.

 

My capture process has been to open my camera in sharpcap. Goto my target and center it.  Then I adjust the capture area, exposure and gain to get an acceptable image.  Next I manually do a rough focus and attempt to use the focus tool available in Sharpcap, specifically the Contrast Edge Detection. I follow the graph data and peak the green bars but at this point I can see I need to tweak it manually again to get a better focus.  The tool alone does not get it done.  One factor here I have not investigated is humidity. On any given observing night the humidity can be 75% to 95%.  My dew shield is very effective at keeping it off my corrector plate but it is still in the atmosphere.  Does all that water vapor cause a focus issue?

 

Bill



#4 dcaponeii

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Posted 15 October 2021 - 11:54 AM

I found that the 12v output of my LX600 focus port was slewing the focuser too fast and I’d overshoot the focus point. I’m not autofocusinv either but switching back to the focuser’s 9v hand controller made a huge difference. I’m watching Borodog’s experience with autofocus and might get one if his results continue to be positive.

#5 Borodog

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Posted 15 October 2021 - 01:01 PM

Try using the Fourier Detail method instead of the Contrast Edge Detection method.



#6 Timberwolf99

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Posted 15 October 2021 - 04:53 PM

Good input guys.  I will look into both of these.   Headed out of town for a week so it will be when I return

 

Bill



#7 Timberwolf99

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Posted Yesterday, 02:02 PM

I had time over the weekend to get back on this.

 

Focuser is definitely not overshooting.  The Celestron focuser gets its power from the AUX port.

I can step it very slowly and get a good visual focus.  

 

I tried the Fournier Detail method and did have slightly better results.  Not sure if it was the difference in the method or I was just being super patient (as I should be) and got the better results.

 

I am going to upgrade to Sharpcap Pro and see if the autofocus will make a difference. 

 

Are there any post processing tips that would improve my results?

 

 

Thanks for the help.  Any other suggestions, please post them smile.gif

 

Bill



#8 Kiwi Paul

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Posted Yesterday, 07:28 PM

I don’t think the level of water vapour in the air would have any effect on focusing (apart from due formation!)
Paul


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