Focuser Replacements and Motorised Focuser

[leinad]

Hi all,

I'm looking at replacing the focusers on both my Orion ST80 and Saxon ED80, and getting a motorized focuser unit for the new ED80 focuser.

From what I've read; for the ED80 I should be able to use the GSO 2" 96mm 10:1 Focuser or the WO F-SYN2S-N NEW GENERATION 2" Crayford focuser with 10:1 2-speed microfocuser.

The latter is more expensive; but is there any real difference that is noticeable?

Also do these support motorized focusing. Is there a better unit that supports motorised focusing.

For the ST80 Im looking at the Bintel Crayford Focuser 10:1 Refractor (88mm OD). I think this is the right one I need.

For those that have done similar before, can you recommend best focuser that can use a motorized focuser; and what focuser will work with it. Also, does the replacement focuser need regreasing?

Thanks heaps. :D

[dugnsuz]

I have the 88mm GSO focuser for my AOE 80mm f7.5 guidescope.
It replaced the very crappy stock R+P that came with the scope. It is way better but not excellent. Having only used a GSO newt crayford for comparison (which I thought was very good for the money) - the refractor focusser drawtube can slip under the influence of gravity unless tightly locked.And careful when locking as this will move the assembly moving your guidestar - not perfect!! Didn't need regreasing, but mechanically a tight fit to get it onto the scope!!
I would certainly go for the WO or similar(not GSO) on your imaging scope.
All the best
Doug

[monoxide]

i used the JMI Motofocus/PC focus with a GSO 10:1 and i was suprised how well it worked for a cheap setup.

its not going to give you instant repeatable focus to the same spot for each filter like the expensive ones but if you focus by numbers it takes no time anyway. i actually miss it since i started using the Tak instead of my 6" newt

the GSO 10:1 can be a bit smoother if you re-grease it but its not really needed if using the motofocus, that doesnt really care how smooth or not the focusser is aslong as its not really bad.

[leinad]

The R&P focuser on the Orion ST80 is really drivinf me nutz with the guidestars. It moves the guidestar left/right when turning the knobs which is annoying!
Yes, definitely not wanting a cheap GSO on the imaging scope. Leaning towards WO focuser and some motor focuser to go with it?



Thank monox; I'll check that out also. May be useful for my 203mm Newt.
This one?: http://www.myastroshop.com.au/products/details.asp?id=MAS-287

[monoxide]

thats the one, thats only the PC focus part though.

this is the actual motofocus that it plugs into:
https://www.bintelshop.com.au/Product.aspx?ID=7677

the motofocus works fine by itself, you dont really need the pc focus part.
the hand controller only has a short cable though but can easily be replaced with whatever length you like with about $5 of stuff from DSE.

i just got the PC focus part since im trying to make sure i can operate everything remotely.

[leinad]

Whoa! didnt think it would cost that much. almost the same cost as the focuser itself; unless I'm missing something.

[monoxide]

depends what your going for though really, the full GSO setup with pc control probably works out to cost a little less than a JMI motorised focuser.

the way i see it, once motorised it wouldnt matter if the focuser was a gso or a feathertouch, its going to work the same way since the motor wont care how smooth the motion is (aslong as there is no slop in the drawtube).

it took a bit of fiddling to get it set the way i wanted it but once it was going, it was worth every cent :)

[leinad]

Correct me if I missed it monoxide, but was the focuser change you did for your newt or ED80 ?

Im curious what focusers others/yourself have used for the standard ED80 R&P focuser.


Does the ST80 and ED80 have the same internal outside tube diameter.
If Im to get a new focuser, I just wanna be sure I get the right one.

[dugnsuz]

ED80 requires 96mm focuser, ST80 would be the 88mm version I think.
Others hopefully will confirm.
Doug

[Merlin66]

I've just replaced the focusers on both the ED80 and the ST80; they have the "standard" 86mm inside diameter tube.
I used the TS 2" Crayford on both; works very well.
The one on the ED80 is motorised using the standard Skywatcher/ Orion DC motor; needed a small mod to the mounting bracket, no big deal and I can post photos if needed to help.
This motor works with the Shoestring adaptor and allows PC control.
A couple of great little set ups that just do what they're supposed to do.

[leinad]

Hey Merlin,

Can you provide me with some photos, more information on the focusers and Skywatcher PC Focus you got. This looks like a good option to me.

I can always upgrade later on down the path.

Where did you buy them from?
Is this the one? http://www.telescope-service.com/ATM/focusers.html#REFok

Im leaning towards the Bintel Crayfor 10:1 for the ST80; not sure what option to go for the ED80 as yet.

[monoxide]

i used it on my newt but it fits refractor focusers too.
the orion focus motor works with gso focusers but you need to make your own adapter to fit it on the shaft i think?

this crayford fits ED80's https://www.bintelshop.com.au/Product.aspx?ID=7467

[leinad]

Monoxide..

Could you send me some pics or info on how you modded this adaptor ?

Thanks. :D

[monoxide]

http://www.iceinspace.com.au/forum/showthread.php?t=10782&highlight=orion+accufocus

that should help you out a bit

[Merlin66]

The TS focuser, I think is just a re-badged GSO. Widely available over here in the UK. I bought mine s/hand on the forum.
The attached images show the small bracket cut and bent from a bit of 1mm aluminium.

[leinad]

Thanks.

[leinad]

Bintel(GSO) focuser for the ST80 arrived today. Unfortunately no instrcutions were included.
Can someone advise that these screw adjustments are as below:

- The screw closest to the eyepiece end is for focuser tension; if I loosen this the barrel moves freely.

- The screw behind the above(towards lens end) is a locking screw ?

Thanks.

[Merlin66]

That's 100% correct!!!
Don't know why we never seem to get any instructions; same over here!

[leinad]

:thumbsup: Thanks for confirming. It has a few screws loose. One was at the bottom of the box. :scared: Glad it was there though. Small countersunk screw. I gather these were assembled in store, and when placed in the box or in transit the screw loosened itself. :sadeyes: screwed back in now though, cant wait to get home and install on the ST80. :D

[Robster]

Hi Guys,

Haven't posted for a while because my scope has been packed away till I can get it to do what I want. It is a Celestron Nexstar 130SLT which came with a very poor focuser which does the shimmy shake whenever I am trying to focus on an object. I've scoured the various Australian Astronomy shops online but I haven't found any that have a replacement motorised focuser to fit my 130mm diameter OTA. The closest I've seen is a Crayford focuser from Bintel which is for a 200mm OTA.
Does anybody know of a supplier who would have a focuser to fit my scope? I want to get back into observing - I even bought a NextImage camera to fit to the scope but it's a waste of time with the original focuser.:( Have any of you made a successful replacement of the OEM focuser on your Newtonian Reflector scopes? (Most mails I see are by owners of SCT scopes and are of little benefit to me!)