Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

SCT focusing with an EAF

  • Please log in to reply
3 replies to this topic

#1 mikeinlehigh

mikeinlehigh

    Mariner 2

  • *****
  • topic starter
  • Posts: 230
  • Joined: 03 Jul 2020
  • Loc: Southwest Florida

Posted 11 December 2023 - 02:37 PM

I've been manually focusing my C8 SCT for astrophotography using a bahtinov mask. I've now installed a ZWO EAF and will use the NINA auto focus feature that I've been using all along on my refractor. I've always finished my manual focusing on the SCT with a final small turn counterclockwise as advised by many. If using autofocus, what do I do about that counterclockwise finish? What do you do?

 

Mike



#2 idclimber

idclimber

    Fly Me to the Moon

  • *****
  • Posts: 5,908
  • Joined: 08 Apr 2016
  • Loc: McCall Idaho

Posted 11 December 2023 - 03:03 PM

With the focusing programs that I have used it always approaches a focus point from a single direction to accommodate any backlash. I can also change the direction of that movement in the setting panel. You should be able to see which direction the focuser is moving, if you want it moving counterclockwise just reverse the setting if it is wrong. 


  • Bean614 and aabusara like this

#3 tosjduenfs

tosjduenfs

    Messenger

  • *****
  • Posts: 468
  • Joined: 03 Jan 2017

Posted 12 December 2023 - 03:59 AM

In the NINA autofocus settings set the backlash compensation method to 'Overshoot'  then set the backlash IN/OUT steps to some fairly large number.  I use 2500 steps with an EAF on my edge (2500 steps might be overkill but I want to be sure to take up all the flop of the mirror).  If you set the backlash IN steps to 2500 and run an AF and see it went the wrong way on the final move then simply set IN to 0 and set OUT to 2000 and it should rotate the correct direction on the last move.

 

Screenshot 2023-12-12 025753.jpg

 

This is what my AF settings look like for an EdgeHD 8.  My EAF is reversed compared to most so you'll probably want to try IN steps first rather than OUT.


Edited by tosjduenfs, 12 December 2023 - 04:01 AM.


#4 mikeinlehigh

mikeinlehigh

    Mariner 2

  • *****
  • topic starter
  • Posts: 230
  • Joined: 03 Jul 2020
  • Loc: Southwest Florida

Posted 12 December 2023 - 08:13 AM

Thanks Tosjduenfs. Really appreciate the info. Will give me a starting point waytogo.gif


Edited by mikeinlehigh, 12 December 2023 - 08:28 AM.

  • tosjduenfs likes this


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics