fitting a celestron focus motor to a RASA8

[h0ughy]

well if i can do it anyone can, how hard can it be!:question:

to be honest i didnt have any dramas, used a bit of tape to hold a bracket in place and remembered not to over tighten and strip the plastics....;)

have to wait for some camera extension adapters before i can test the focusing - :lol: no visual eyepiece:rofl::help::screwy:

[Dennis]

Very nice David, but does it sound like a purring Maserati Quattroporte when it operates...;):lol:

Cheers

Dennis

[h0ughy]

When I fire it up I could dream, but I fear that it will be a datsun 120y:lol:

[The_bluester]

One thing to periodically check on on these, the lock ring you can see over the thread on the main shaft came loose on mine which allowed the main gear to move around on the bearing, it started fouling on the housing and jammed the motor. It was doing it occasionally for a while and makes the motor behave strangely, it will move then you suddenly hear it move much faster than normal for a moment and stop suddenly. Eventually it just refused to move and that is when I worked out what was going on.


I reckon an occasional maintenance tweak of that lock ring/nut would be wise and if it starts moving unpredictably, the first thing to check.

[astrod]

Looks good. I have the same focuser on a RASA 8 in operation (literally right now as I type). I've had near zero issues with the focuser; it is not noisy and works exactly like another motorised focuser I have on a small refractor. A new youtube video link (https://www.youtube.com/watch?v=8GSK99RPono) tends to trash the focuser but it is far from my experience. Roughly you should get 30000+ counts ranging from fully in to fully out (and this is about 30 revolutions of the focuser knob). I run it through USB and connect through SGPro. Did I say zero issues? Actually if you connect it via the AUX connect to a Celestron mount then it seems to port share with the mount and SGPro won't let you use both at the same time. That's why I used USB.

[The_bluester]

With the lock ring sorted my only real criticism of the focuser is the lack of a temperature sensor built in. It is noisy compared to the ZWO one on my refractor, the difference really being the Celestron makes an audible noise, and the ZWO is as good as silent, but it does not bother me.

The lack of a temperature sensor is my only real gripe, given how sensitive the SCT is to temp changes.

[h0ughy]

I have a temperhum that I bought ages ago and haven't used yet. I will have to get it working after I find it

[The_bluester]

I have one too but I have had no success getting it working in SGP as it does not recognise them. I had a play with the ASCOM driver that is elsewhere on these forums but it is not a device that works with that (Given how many different versions of a "Temperhum" there are) and then I bought the refractor and ZWO focuser so I never went any further with it.

When I use the SCT I just have SGP set up to focus in the best tradition of elections, vote early and vote often, figuring it is better to lose the equivalent of a couple of subs time wise over the night to focus runs compared to getting a lot of throwaway, out of focus subs. It will be interesting to see how touchy the RASA is to temperature changes, the lack of a magnifying secondary mirror might actually make them better than an SCT.