Motorised focuser for WO Megez/generic refractor - any suggestions?

rogerg (Roger) · #1 25-09-2006, 01:41 PM

I'm looking for a focuser motor to put on my William Optics Megrez 80 (SD, the original version). I'm just after something very simple and low-tech. I have RoboFocus on my LX200 but it's too expensive and more than I need for the Megrez (portable setup). The focus knob of the megrez can be taken off to just leave a shaft able to be connected to.

I'm really just after a motor with fixed or variable speed that can somehow turn the focuser knob, and be controlled by 2 buttons (in and out), or through a computer.

One option I have found is the Orion Acufocus. This looks ideal except I am unsure if I can somehow mount it on my Megrez.

Another option I considered is putting something like a meade micro focuser between camera and 2" draw tube. This is not preferred because it takes up extra back focus and is more expensive, assuming I can mount it on a 2" draw tube.

I have even considered buying a stepper motor kit from Jaycar for $49 which plugs into the computer's LPT port, disadvantage here is it isn't made to fit the scope focuser and would need some sort of gear (minimum $90 from Farnell, if it fits the motor).

So, could anyone offer help:

1) anyone have one of the Orion Acufocusers to take a close up photo and measurements of it's connector?

2) anyone have other suggestions?

Thanks,
Roger.

Merlin66 (Ken) · #2 25-09-2006, 01:56 PM

I'm using the Orion on my Genesis. As the TV shaft is actually tapered I had to use a small 8mm spacer to fit the Orion and add a small adaptor plate to the mounting on the bottom of the focusser... no big deal. Works a treat.

rogerg (Roger) · #3 25-09-2006, 03:12 PM

Quote:

Originally Posted by Merlin66

I'm using the Orion on my Genesis. As the TV shaft is actually tapered I had to use a small 8mm spacer to fit the Orion and add a small adaptor plate to the mounting on the bottom of the focusser... no big deal. Works a treat.

Thanks... sounds encouraging. Any chance you could send through a pic or 2 showing a closeup of the arangement? If it's too much hassle don't worry.

Thanks,
Roger.

Merlin66 (Ken) · #4 25-09-2006, 03:35 PM

Won't get home until the weekend, if you can wait that long!!

rogerg (Roger) · #5 25-09-2006, 04:28 PM

Ahh, thanks - don't worry about it.

I have since done a tone more internet searching and got some info from Don @ BINTEL about it, and have just gone ahead and ordered the Accufocus. It seems like the ideal solution.

I don't think I'll have any troubles attaching it to my Megrez but if I need to I'll have a little coupler machined up to make it fit.

Roger.

Astroman (Andrew Wall) · #6 25-09-2006, 05:06 PM

I have the accufocus on my NGF-DX3, works great, I did have to make a small coupler to go inside the flexable coupler on the accufocus. If you can make a small bracket to hold the accufocus it will work great. The other option is to use the accufocus with a belt drive on the focus knob.

rogerg (Roger) · #7 29-09-2006, 09:38 AM

I was surprised to receive my Accufocus yesterday after only ordering it early in the week. I was even more surprised to get it attached in the one night & morning to a scope it wasn't designed for!

Conveniently, the bolt that is meant to hold the tripod plate to the Megrez is perfect for attaching a bracket to for holding the focuser motor, amazing.

I haven't tried it out on the stars yet, but works great in daylight this morning. Seems like great value for money. A little backlash in it which my RoboFocus doesn't have but that's the difference of $400 I guess.

Attached a few pic's for interest sake.

Roger.

Yogie-One (Paul) · #8 26-02-2007, 10:00 PM

have a setup for my scope, which uses only a battery, a 12 position switch, 8 diodes, a 5 or 6 wire stepper motor, a mounting plate and a few gears.

The conection causes the stepper motor to follow the switch, forward or backwards, enabling it to be used as a driver for a focuser.

Total cost $3 (with stepper motor from old printer)

http://www.iceinspace.com.au/forum/i...c/progress.gif

[1ponders] (Paul) · #9 26-02-2007, 10:16 PM

JFYI, Bintel used to sell the Orion Accufocuser for about $89. They now sell the identical Skywatcher for $59.

jase (Jason) · #10 27-02-2007, 03:33 AM

Roger,
Actually RoboFocus isn't that expensive... The expense is with the controller, not the stepper motor and mounting. If you use FocusMax, then load different profiles based on what scope you are controlling. That way you can use the same controller.

rogerg (Roger) · #11 27-02-2007, 10:10 AM

The RoboFocus stays permanently mounted on my LX200. I'm not going to go taking it or even its controller off and putting it on my portable mount whenever I go out in the field, that'd be a royal pain in the... And then there are the times I use both at the same time, at home.

The Orion does a great job, have been using it many months now with great success. I wouldn't use it on the LX, it doesn't suit the situation, but on small refractors it's great.

Roger.