Jump to content


Photo

Using SBIG St-237 on a Losmandy G-11 Gemini

  • Please log in to reply
7 replies to this topic

#1 powerstroke01

powerstroke01

    Viking 1

  • -----
  • Posts: 531
  • Joined: 19 Jun 2007
  • Loc: Western Sierra Nevada Foothills

Posted 14 March 2010 - 02:43 PM

Im reallllyyyy confused now. Ive been doing lots of reading and have read that i need to use an Optocoupler with this camera/mount... First off... WHY?
Ive also read that i dont need one. But i was unsure why.. Could someone explain this to me? lol
I just want a definate answer.. :help:

And has anyone used this camera with this mount as an autoguider?

Sorry for all the questions. :foreheadslap:

#2 powerstroke01

powerstroke01

    Viking 1

  • -----
  • Posts: 531
  • Joined: 19 Jun 2007
  • Loc: Western Sierra Nevada Foothills

Posted 14 March 2010 - 02:46 PM

And yes i have the round din connectors... if that helps.

#3 jrcrilly

jrcrilly

    Refractor wienie no more

  • *****
  • Administrators
  • Posts: 33795
  • Joined: 30 Apr 2003
  • Loc: NE Ohio

Posted 14 March 2010 - 02:48 PM

The standard 492 controller requires isolation; the Gemini controller does not.

#4 bseltzer

bseltzer

    Apollo

  • -----
  • Posts: 1028
  • Joined: 28 Oct 2007
  • Loc: East S.F.Bay, CA

Posted 14 March 2010 - 02:56 PM

The definite answer is "It depends..." :grin:

Seriously, which incarnation of the Gemini do you have? If it has the rectangular RJ-something-or-other connections to the motors, then an opto-coupler would be a good idea. Helps to prevent ground loops. OTOH, if your Gemini is the more recent type with round, DIN type motor connectors and the lighted rocker type on/off switch, then you'll probably be fine without an isolating autoguider cable.

I have the later version Gemini and have done auto-guiding with both an ST-4K and ST-2K without an opto-coupler cable with no problem whatsoever. That said, I went ahead and bought one of Tom H.'s opto-coupler isolated cables on the theory that it was cheap insurance since mine is a mobile set up, and the array of things I have connected to my power source changes from time to time.

Regards,
Bert

#5 powerstroke01

powerstroke01

    Viking 1

  • -----
  • Posts: 531
  • Joined: 19 Jun 2007
  • Loc: Western Sierra Nevada Foothills

Posted 14 March 2010 - 03:09 PM

The definite answer is "It depends..." :grin:

Seriously, which incarnation of the Gemini do you have? If it has the rectangular RJ-something-or-other connections to the motors, then an opto-coupler would be a good idea. Helps to prevent ground loops. OTOH, if your Gemini is the more recent type with round, DIN type motor connectors and the lighted rocker type on/off switch, then you'll probably be fine without an isolating autoguider cable.

I have the later version Gemini and have done auto-guiding with both an ST-4K and ST-2K without an opto-coupler cable with no problem whatsoever. That said, I went ahead and bought one of Tom H.'s opto-coupler isolated cables on the theory that it was cheap insurance since mine is a mobile set up, and the array of things I have connected to my power source changes from time to time.

Regards,
Bert


Thanks! I have the version with the round plugs and the lighted rocker switch..

#6 bseltzer

bseltzer

    Apollo

  • -----
  • Posts: 1028
  • Joined: 28 Oct 2007
  • Loc: East S.F.Bay, CA

Posted 15 March 2010 - 01:05 PM

Thanks! I have the version with the round plugs and the lighted rocker switch..


Then you should be good to go. Be aware that if you connect the guider cable to the Gemini before you have the camera under software control, you likely will get a guider port error message from the Gemini. This is normal because the camera may send what the Gemini interprets as contradictory signals to the guider port until whatever camera software you're using gets control of it. This is annoying, but harmless. It's another reason to get the Tom H. isolater guider cable. It does away with these spurious error messages.

Regards,
Bert

#7 powerstroke01

powerstroke01

    Viking 1

  • -----
  • Posts: 531
  • Joined: 19 Jun 2007
  • Loc: Western Sierra Nevada Foothills

Posted 15 March 2010 - 02:59 PM

Thanks!
I just dont want to fry something.. heh
Do you have a link to that isolator guide cable?

#8 bseltzer

bseltzer

    Apollo

  • -----
  • Posts: 1028
  • Joined: 28 Oct 2007
  • Loc: East S.F.Bay, CA

Posted 15 March 2010 - 03:55 PM

Don't have a link, but you can reach Ton Hilton at tom@arizonaskys.com. He's not making these commercially any more, but he does turn them out on an "as needed" basis when he gets enough requests.

Regards,
Bert






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics