electric focuser for c14

[icytailmark (Mark)]

i am looking at buying a electric focuser for my c14. I have been trying to image mars but everytime i turn my focus knob i lose mars off the center of my camera.

http://www.myastroshop.com.au/produc...sp?id=MAS-051C

Would this be a good focuser?

[pmrid (Peter)]

Originally Posted by icytailmark

i am looking at buying a electric focuser for my c14. I have been trying to image mars but everytime i turn my focus knob i lose mars off the center of my camera.

http://www.myastroshop.com.au/produc...sp?id=MAS-051C

Would this be a good focuser?

The JMI line of electric focusers is good. I have 2 of them and can report that they work well and are easily controlled from the PC.
The thing about these focusers is that you don't need a great deal of travel in the drawtube since the coarse focus is done with the standard SCT focuser. Set the drawtube to a mid-point and get your rough focus set for there, then don't touch it again.
The problems can occur where you use a reducer - the standard Celestron .63 reducer is designd to screw onto the rear cell of the scope. That means you can't put a focuser like this onto the scope.
What you need is a focuser that can accept a reducer in the end of the drawtube so it moves with the drawtube - i.e. you maintain a precise and constant back-focus and stilla are able to screw the body of the focuser onto the rear cell. Moonlite make a line of focuser with the ability to accept a reducer like that.
Peter

[icytailmark (Mark)]

peter can you take the reducer out when you wanna image planets?

[Poita (Peter)]

I use one of these, and have been very happy with it.
http://www.optecinc.com/astronomy/catalog/tcf/tcf-s.htm

[pmrid (Peter)]

Originally Posted by icytailmark

peter can you take the reducer out when you wanna image planets?

Yes. It does mean taking the whole focuser assembly off and unscrewing the reducer. In reality it is only a 2 minute job, but just a pita.

Peter

[asimov (John)]

I've been using the EV-3c for 4 years now & love it. It's that good that I took the motor off it though & use it manually.

[Merlin66 (Ken)]

Mark,
On my C11, I use a SW focus motor, belt drive to the existing knob.
This allows me to accurately focus the target star onto a 20 micron spectroscope slit.
Cheap and works well. Using the Shoestring FCusb connection I can control the focus from the PC.
( I left the Vegemite manual fine focus knob in place...)