Moonlite Focusser Query

[wackyscot]

Hi all, 

I'm sure this has been asked a thousand times, but I'm having trouble achieving focus with my dslr on my Skywatcher Dob. I bought the scope with an upgraded focusser. It has  a Moonlite CR1. I've not stripped it down yet as I was worried I may make it worse. 

The picture shows 2 spacers, (highlighted them with yellow) can these be removed, or do they need to be there. My thinking is, if they are removed will I be able to achieve focus, any help would be great.

 

Thanks

David

[tooth_dr]

Hi

Yes you can easily remove either one or both of the spacers.  I did this with mine to try to get focus with binoviewers - this was unsuccessful.  You could try removing just one first then see if you can get focus.  The other issue will be screw length.  You could either cut yours or buy shorter ones.  I was fortunate to get some screws off a member on here, someone else might have some.  Just keep the tube horizontal so nothing falls off and into the mirrors.  If you make the focuser lower then EPs may need an extension, but the middle of the focuser slides out so that should compensate for it.

I actually just noticed there that your scope is the same as mine I think (300PDS?) and the focuser is the same, and just last night i was thinking of using it for some deep sky imaging.  I'm might actually take a look at this this evening, so if you can hang on I can try out what spacers are needed.

 

 

 

 

 

 

 

[wackyscot]

7 minutes ago, tooth_dr said:

Hi

Yes you can easily remove either one or both of the spacers.  I did this with mine to try to get focus with binoviewers - this was unsuccessful.  You could try removing just one first then see if you can get focus.  The other issue will be screw length.  You could either cut yours or buy shorter ones.  I was fortunate to get some screws off a member on here, someone else might have some.  Just keep the tube horizontal so nothing falls off and into the mirrors.  If you make the focuser lower then EPs may need an extension, but the middle of the focuser slides out so that should compensate for it.

I actually just noticed there that your scope is the same as mine I think (300PDS?) and the focuser is the same, and just last night i was thinking of using it for some deep sky imaging.  I'm might actually take a look at this this evening, so if you can hang on I can try out what spacers are needed.

 

 

 

 

 

 

 

My scope is 12" Dobsonian, flextube. Thanks for the info, looking forward to seeing how you do

[Piero]

If you need more inward travel to reach focus, you should remove those spacers. If you need more outward travel you need an extension tube.

Removing those spacers is easy. You need a hex key to detach the four screws holding the focuser. 

Don't touch the two screws at the bottom near the Moonlight text. Those are for collimation of the focuser.

[tooth_dr]

On 02/11/2017 at 11:16, wackyscot said:

My scope is 12" Dobsonian, flextube. Thanks for the info, looking forward to seeing how you do

Hi David. It hasn’t been clear but I did try it last night on distant street lights I could see (20 miles away approx) and I was able to focus without removing spacers. I’m not sure if this will be infinity, and I only had a couple of mm spare. Will try next clear night. I’ve attached a photo of my camera attached  

 

[wackyscot]

I mucked around yesterday afternoon, seems I need outward focussing. Handheld the camera and got focus - I also tried removing the spacers with no success. I got focus with an extension.

[wackyscot]

8 hours ago, wackyscot said:

I mucked around yesterday afternoon, seems I need outward focussing. Handheld the camera and got focus - I also tried removing the spacers with no success. I got focus with an extension.

Scrub the above, tried the moon, inwards focus, removed the spacers and bingo. I have an extension tube which i tried for visual, too flippin long lol. So I need a shorter extension tube for visual. Aaaaargh

[tooth_dr]

15 minutes ago, wackyscot said:

Scrub the above, tried the moon, inwards focus, removed the spacers and bingo. I have an extension tube which i tried for visual, too flippin long lol. So I need a shorter extension tube for visual. Aaaaargh

I tried the moon there and I can actually just get focus with both spacers as per photo so looks like my focuser must be positioned different in relation to the primary.