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

Automatic, not electric, focusing assistance for Disabled

beginner cassegrain Celestron equipment SCT
  • Please log in to reply
6 replies to this topic

#1 Notdarkenough

Notdarkenough

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 17 Jan 2021

Posted 24 January 2021 - 08:11 AM

Hello all. Another stinkin’ newbie here. I have the 60th Anniversary NexStar Evolution EdgeHD 8 SCT, and added the Focus Motor from Celestron. I still need something to help me achieve focus. For background, I am a Disabled Veteran. The first problem we found was my lack of fine-motor control, and the electric focus motor is wonderful for mitigating that difficulty. However, the injury to my brain also impacted my eyes' ability to track movement; watching the image adjust while trying to focus is problematic. Is there some piece of equipment that can actually achieve rough focus automatically? I am a visual observer, no photography. Does anyone know of anything that might fit the requirement? Thank you for sharing your hard-won expertise on this site. Mike



#2 imtl

imtl

    Mercury-Atlas

  • *****
  • Moderators
  • Posts: 2,883
  • Joined: 07 Jun 2016
  • Loc: Down in a hole

Posted 24 January 2021 - 08:18 AM

Hi Mike,

 

Welcome to CN and thank you for sharing your story.

 

Going with a motorized focuser is a good way to go. Are you using a bahtinov mask to focus? It might be easier for your eyes to track the changes in focus with the bahtinov spikes.


  • Dynan likes this

#3 Notdarkenough

Notdarkenough

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 17 Jan 2021

Posted 24 January 2021 - 08:55 AM

No, no use of the masks. I looked the Bahtinov up, but don't understand how it would interact with the motor. I have my input (tablet or HC) and my eyeball at the eyepiece. Thanks for getting this post in the right place. Mike



#4 Phil Sherman

Phil Sherman

    Gemini

  • *****
  • Posts: 3,301
  • Joined: 07 Dec 2010
  • Loc: Cleveland, Ohio

Posted 24 January 2021 - 11:21 AM

Bahtinov masks do not interface with a motor focuser. They change the image you see so a bright star appears with two lines through it making an "X". Third line moves up and down through the "X" with focus achieved when the third line is centered where the center of the "X" is. They make visual focusing very easy.

 

The Bahtinov mask is placed over the corrector plate or dew shield if you have one. After focusing, you remove the mask and observe.



#5 Notdarkenough

Notdarkenough

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 17 Jan 2021

Posted 24 January 2021 - 11:48 AM

Yes, that is my understanding. What I don't understand is how that is to help. I will certainly try it; I am certainly grateful for the idea. What I don't understand is why something so simple has been missed by tech advisors from the local D1 Research University, Celestron, High Point Scientific, etc...

 

Regardless of what I don't understand, which is stunning, I am grateful for the time given and advice provided. Thanks again, Mike



#6 Dagobert

Dagobert

    Ranger 4

  • *****
  • Posts: 350
  • Joined: 22 Oct 2004
  • Loc: Cincinnati, OH

Posted 24 January 2021 - 02:13 PM

Mike,

Autofocus requires an image sensor.  In a typical DSLR set-up the image sensor is parfocal with its viewfinder.  You don’t find that same configuration in astronomical telescopes.  Not saying it can’t be done but it would be a fairly elaborate customized setup involving a prism (might be able to employ an off-axis guider), imager, computer (nuc), autofocus software, and parfocal visual lightpath to your eye and of course a focus motor compatible with the the software.  I’m going to guess that the trickiest part is managing that lightpath to be parfocal.  
 

The bahtinov mask is very simple and inexpensive to try.  It is going to present your eye with a variable light pattern that gives a singular visual cue to focus compared to an entire field of stars for example.  One just needs to point the scope at a bright star.  It might give you the assist you need, might not but probably worth a try.


If not, you might reach out to your nearest astronomy club.  There you will find folks nearby who would likely fall over each other to help you solve it.  As I say, nothing off the shelf does exactly what you want.  But this hobby is full of people who are drawn to it for that very reason waytogo.gif

 

good luck!



#7 Notdarkenough

Notdarkenough

    Lift Off

  • -----
  • topic starter
  • Posts: 12
  • Joined: 17 Jan 2021

Posted 24 January 2021 - 04:44 PM

Thank you for the information and answers. It is very helpful. A FarPoint Tri-Bahtinov mask for EdgeHD HyperStar compatible is enroute. Hopefully, local clubs will be back soon!

 

For forum bosses: I really enjoyed reading about the articulating eyepiece solution for wheelchair users. Luckily, I can still move my upper-half enough to not need that type of solution. Am I the only one seeking disability-assistance advice? I figured there had to be enough for a dedicated space for broke-people (not broke-wallet) assistance. I know lots of, umm, seasoned? astronomers linger eternally here at CN, and we all get broken eventually! Hopefully accessible astronomy gear is a growth industry. Certainly there is no need to stop staring into the night just because one isn't 30 anymore! 


Edited by Notdarkenough, 24 January 2021 - 04:48 PM.



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





Also tagged with one or more of these keywords: beginner, cassegrain, Celestron, equipment, SCT



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics