Focus

[Jiggy 67]

I have recently fitted the moonlight CR2 Dual Speed Focuser to my SW 200PDS. The one I fitted has the standard 50mm travel.

I love the focuser but I have noticed that it does not have enough travel to accommodate my 40mm TV Plossl ep......very annoying, it runs out of travel (outwards) just before it can achieve focus. I used the installation kit and fitted both spacers. I have looked at some extenders but they all appear to be for specific telescopes and for astro photography (don't know if that makes any difference). Can anyone recommend an extender or suggest any other solution?

 

[johninderby]

You can get one of these extenstion tubes although there are cheaper equivelents.

https://www.firstlightoptics.com/adapters/moonlite-15-focus-extension-tube.html

Cheap but will do the job.

https://www.amazon.co.uk/Gosky-Astronomical-Telescope-Eyepiece-Extension/dp/B07CSPN8R1/ref=sr_1_6?keywords=2”+eyepiece+extension+adapter&qid=1581095064&sr=8-6

Edited February 7, 2020 by johninderby

[Jiggy 67]

 

 

 

2 hours ago, johninderby said:

You can get one of these extenstion tubes although there are cheaper equivelents.

https://www.firstlightoptics.com/adapters/moonlite-15-focus-extension-tube.html

Cheap but will do the job.

https://www.amazon.co.uk/Gosky-Astronomical-Telescope-Eyepiece-Extension/dp/B07CSPN8R1/ref=sr_1_6?keywords=2”+eyepiece+extension+adapter&qid=1581095064&sr=8-6

Thanks John....but how would that work with 1.25" ep's. I assume you would move the 1.25' adapter from the focuser, insert the extension tube and then replace the adapter into the extension tube??.....is that correct??

[johninderby]

Yes that’s right. Fit the 2” extender in the focuser and then put the 1.25” adapter into the 2” extender.

👍🏻

[John]

At least it will only be the TV 40mm plossl that will give this issue - they are not par-focal with other TV plossls or most other TV eyepieces, as you have found their focus point is somewhat further outwards.

Better that than not enough inwards travel ! - at least an extension tube on the focusser can solve your issue for this eyepiece. Depending on how far it is out, a par-focalisation ring on the eyepiece barrel can do the same.

 

 

[Oldfort]

The Televue high hat 2" to 1.25" adapter might give the extra distance you need.  Of course, being Televue, it won't be cheap.

[markse68]

On 07/02/2020 at 17:51, Jiggy 67 said:

I have recently fitted the moonlight CR2 Dual Speed Focuser to my SW 200PDS. The one I fitted has the standard 50mm travel.

...Can anyone recommend an extender or suggest any other solution?

 

There’s a German ebayer - “classic-telescopes” listing 2.37” moonlite tubes for about £30 delivered. A LOT cheaper than direct from moonlite! Or maybe you could adjust your primary mirror back a bit with the collimation screws if it’s just too short?

Edited February 9, 2020 by markse68

[Jiggy 67]

On 07/02/2020 at 22:08, John said:

At least it will only be the TV 40mm plossl that will give this issue - they are not par-focal with other TV plossls or most other TV eyepieces, as you have found their focus point is somewhat further outwards.

Better that than not enough inwards travel ! - at least an extension tube on the focusser can solve your issue for this eyepiece. Depending on how far it is out, a par-focalisation ring on the eyepiece barrel can do the same.

 

 

I’m not sure that I am a big enough fan of the eyepiece to bother doing anything!! Considering putting it up for sale