8 replies to this topic

[bshay]

Hey folks! 

 

So I picked up a beautiful old Celestron SPC-6 Newtonian with the wooden ED mount on Facebook Marketplace for $130.  It has a "sled" style focuser that moves the secondary mirror further and closer away from the primary, which I've never seen before.  Does it matter what position on the sled the eyepiece is in when I collimate it?  At first I thought I mattered but now upon reflection (ha!) it seems to me that since the sled is simply focusing the eyepiece, it doesn't matter.  At any rate, if anyone has knowledge or experience on this I'd appreciate it! 

 

Thanks!

[mazdak]

Hey folks! 

 

So I picked up a beautiful old Celestron SPC-6 Newtonian with the wooden ED mount on Facebook Marketplace for $130.  It has a "sled" style focuser that moves the secondary mirror further and closer away from the primary, which I've never seen before.  Does it matter what position on the sled the eyepiece is in when I collimate it?  At first I thought I mattered but now upon reflection (ha!) it seems to me that since the sled is simply focusing the eyepiece, it doesn't matter.  At any rate, if anyone has knowledge or experience on this I'd appreciate it! 

 

Thanks!

This telescope was made by Vixen and sold by Celestron. very good quality and smooth mirror .

[Mcloud]

Great buy! The 6 and 4.5 were well respected both use the sled focuser I'm not sure about your question but somebody will chime in I'm sure.

[CHASLX200]

I never had a sled fred on my 4.5's.

[sky_dave]

I've had one since 1991.  So lots of experience with it.  It's best to collimate the telescope with the sled at the position where your eyepiece focus is at.  Having a parfocal eyepiece set helps too.  If you have a laser collimator you can see where the beam hits the primary moves when moving the sled.  You want it to hit the center spot.  But it moves off with motion of the focuser.  This movement can be minimized with some adjustments. You can adjust the focuser ways with an Allen key to take out slop.  The lock screw can be kept just loose enough so you can move the focuser.   After doing this if is still won't stay on center then you have to adjust and or shim the focuser mounting at the mounting screws.

 

Dave

 

[apfever]

Great buy! The 6 and 4.5 were well respected both use the sled focuser I'm not sure about your question but somebody will chime in I'm sure.

The C4.5 never came with a sled focuser, only the C6 which always came with one. 

 

Be careful with the focuser locking screw. Remove it and look at the tip that makes contact. It is like a needle tip that goes into a narrow groove. Don't use it to try to control slop or tension because it will gouge into the sled. I've seen this a lot. 

 

Go to This LINK on CN and the rest of the thread.

Edited by apfever, 26 November 2024 - 09:31 AM.

[stomias]

The comet catcher came with the 'sled focuser'................I never liked it. Sorry, no tips for collimation.

[bshay]

Thanks, friends, for the helpful advice!

[Ducky62]

The Vixen R100S has a sled focuser. I'd say it is more well constructed than the Comet Catcher focuser