Pentax 125SDP vs Taks & others for AP?

[AnakChan]

On 4/16/2016 at 00:14, NickK said:

 

Very nice.. just be concerned about the rear elements for the perzval design. Sorry I've been absent - been rather busy!

Next for me is to work out a robot focuser..

 

Sadly, I've yet to take my scope out for a test and I bought it 5 months ago!

About the robofocus, this isn't the 125SDP but the Vixen VSD100 instead. However since the design is similar, just that the 125SDP is larger, I wonder if the maker (K-Astec) would be keen to entertain the 125SDP too :-

 

[NickK]

4 hours ago, AnakChan said:

Sadly, I've yet to take my scope out for a test and I bought it 5 months ago!

About the robofocus, this isn't the 125SDP but the Vixen VSD100 instead. However since the design is similar, just that the 125SDP is larger, I wonder if the maker (K-Astec) would be keen to entertain the 125SDP too :-

 

 

Beautiful engineering there, however the issue the 105SDP has is that it doesn't have a helical on the main focuser.

 

I have two options - use the rack and pinion focuser that is 1:1 or use a frame around the back end and then have it support the focuser on the borg. The weight on the back of the scope from the camera setup means the borg isn't as free to turn compared to just an eye piece. I will make up something with a pair of hose clamps and a sore thread attached to a servo. See if the small amount of movement required is achievable using a small RC servo. However I'm starting to think that the 1:1 focuser option with a timing band gear box may be a better idea attached to a stepper motor.