Jump to content


Photo

Mirror lock on 10" Classic LX200

  • Please log in to reply
6 replies to this topic

#1 rimcrazy

rimcrazy

    Mariner 2

  • -----
  • Posts: 286
  • Joined: 03 Mar 2012
  • Loc: Overgaard, AZ

Posted 09 January 2013 - 11:21 PM

I picked up a MoonLite focuser for my LX200 and have a question on locking the mirror. I assume the correct proceedure is you want the mirror advanced forward in the tube as far as possible (clockwise) on the focus knob thus pushing the back focus as far as possible out the back and then I need to lock it with a bolt. What is the size and length required so I don't damage the mirror. Do I use the spring/bolt device I've seen written about?

I want to be sure I do this right and not damage anything in the process.

#2 LoveChina61

LoveChina61

    Viking 1

  • *****
  • Posts: 932
  • Joined: 19 Jun 2009

Posted 10 January 2013 - 07:17 AM

I have a TCF focuser and what I did was first use the LX200's own stock focuser to focus my LX200 Classic with a 9mm eyepiece which is about equivalent to my Meade DSI camera's focus distance. That is the camera that I will be using on the Classic. I then locked the mirror down in that focus position.
Then I put on my TCF focuser which only has about 1.5" or so of total focusing distance available. That left me with 3/4" that I could focus inward from the position where my 9mm lens was in focus, and 3/4" that I could focus outward. That will allow me to focus in/out slightly to compensate for any small focusing adjustments that might be needed from one night to another due to "seeing" and the like.

#3 niteman1946

niteman1946

    Ranger 4

  • -----
  • Posts: 314
  • Joined: 16 Feb 2008
  • Loc: Fort Worth, TX

Posted 10 January 2013 - 09:01 AM

My setup is with a feather touch focuser. I set it to roughly halfway on its travel, and then rough focus with the Meade focuser. This is where I set the spring/bolt device.
FWIW, I'm not sure how effective the spring/bolt thing is. But since moving to an OAG, this point is moot.
I would be surprised if you could move the mirror to its full travel and still be able to focus with an external focuser. But let us know if this works.

Good luck,

Mark

#4 rimcrazy

rimcrazy

    Mariner 2

  • -----
  • Posts: 286
  • Joined: 03 Mar 2012
  • Loc: Overgaard, AZ

Posted 10 January 2013 - 09:49 AM

Ah, that makes sense. Had not thought of that but yes, now that you mention it I should use and eyepiece first and use the native focus to put the focus point in the optimal place and then lock it down. I assume you've all used something similar to this:

Chris Vedeler lock method

On this page he mentions that for CCD imaging he uses 3x1" spacers and then just compresses the spring to be locked. Given that how I plan to use this telescope is exclusively CCD imaging, I'm not sure I see the need for putting in a spring that I'm simply going to compress to closed. It appears to me is that if I use something shorter, like a 3" to 4" bolt with just a plastic spacer and a wingnut, I just keep it all loose till I find the ideal position and then just lock the sucker down. I'm not interested in touching the focus knob after that. Am I missing something here or is this correct?

#5 LoveChina61

LoveChina61

    Viking 1

  • *****
  • Posts: 932
  • Joined: 19 Jun 2009

Posted 10 January 2013 - 09:45 PM

That is the same mirror lock that I went with. I think the spring just keeps things from rattling around a bit.

HERE is some more talk on mirror locks for the LX200 Classic.

#6 starrysolace

starrysolace

    Lift Off

  • -----
  • Posts: 10
  • Joined: 11 Aug 2009
  • Loc: Ashburn, VA

Posted 28 January 2013 - 01:02 PM

Sorry can't help with the mirror lockdown but I figured I would say the Moonlite has a getting started doc that mentions you should position the drawtube mid way in, then focus with the primary. Then you can finely focus with the Moonlite.

#7 rimcrazy

rimcrazy

    Mariner 2

  • -----
  • Posts: 286
  • Joined: 03 Mar 2012
  • Loc: Overgaard, AZ

Posted 28 January 2013 - 04:02 PM

Sorry can't help with the mirror lockdown but I figured I would say the Moonlite has a getting started doc that mentions you should position the drawtube mid way in, then focus with the primary. Then you can finely focus with the Moonlite.


Did not read that but I was planning on doing exactly that. I have 3 cameras so I need to set their placement so they are ideally centered at the midpoint of the Moonlite so I have the best flexibility +/-.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics