Connecting auto focuser.

[Robindonne]

Hello.  
What focusknob do i have to remove for installing an autofocusser?

is it best to connect it to the fine-focus axel or doesn’t it make any difference?

Have to decide whether i’m going to use my single-speed sct focusser or forget about this antique item and look for a dual speed.

And if connection must be made on the fine focus knob, does it mean manual fine focus will never be possible? 
 

questioning this because some examples show them on the fine focus side and other on the normal focus side. 

Or is twisting the whole axel-unit possible?
 

thx

Edited May 8, 2020 by Robindonne

[MarkAR]

I've always thought it should be on the standard side, my Lakeside is on my refractor and it works fine.

I would have thought that if it's on the fine focus knob then it'll take forever to go anywhere. The one pictured may be on the fine knob side but could be connected to the main shaft and not the reducer gear.

[Astrosharkey]

NOT THE FINE FOCUSER

[Robindonne]

32 minutes ago, Astrosharkey said:

NOT THE FINE FOCUSER

Sorry cant hear you.  Can you repeat pls?

but serious, thats because you can manually adjust while having the motor attached?

Edited May 8, 2020 by Robindonne

[Astrosharkey]

No if you put it on the fine focuser you wont move anywhere, the steps (if you have a similar one to me) are so small (once you suss it out) that you only need to use the course focus knob.  You cannot use the other focus knob with it fitted.  I know where my rough focus position is and at the start of a session focus out by about @00 steps then focus back in again to get where I need, I also use an auto focus routine on sharpcap which does it all for you.  I also refocus with each filter.

[Robindonne]

Oke very helpful.  So the electric focuser will be attached to the main, single speed, pin, and focusing by hand is not possible anymore?  And then using my single speed focuser will work properly?

Edited May 8, 2020 by Robindonne

[Astrosharkey]

Yep all correct

[Robindonne]

15 hours ago, Astrosharkey said:

Yep all correct

Thx for the help.  
ps. While searching for one i saw a sesto senso 2?  And im not aware of the advantage but while the motor being attached, handcontrol was still possible.  

[DaveS]

Disagree with all the above.

If you are using a Sesto Senso, as it would appear from the photo, then it connects to the Fine Focus knob, as is indicated in the manual. Other motor focusers probably do connect to the coarse focus, but I use the Sesto Senso and connect to the Fine Focus.

SESTO-SENSO-2-EN-user-manual.pdf

[Ken82]

Yes Dave is correct, it is connected to the fine focusing knob. 
 

[david_taurus83]

Agree with Dave and Ken. I use a DSD focuser and the belt drives the fine focus knob.

[bottletopburly]

I use my 200pds on fine knob they work fine whatever suits , my focuser(deepskydad) is belt drive so belt can be slipped off if needed if you wanted to do visual, though I also have a hand controller or use my phone to operate if needed .

Edited May 9, 2020 by bottletopburly

[Robindonne]

Kind of stupid that the design that allows manual-use, deletes the finefocusser, and the ones that dont allow manual-use, spare the finefocuser.  The perfect solution is probably on its way. 
But is it possible to turn the focusknobs around?  So the sesto senso still works but finefocus will be available? Or just mount that senso on the otherside, or mount the whole focusunit upsidedown?

maybe the motor is so weak that it needs the finefocus

Edited May 9, 2020 by Robindonne

[Starflyer]

Fine focus shafts inherently have a load of backlash, with the resolution of the steppers used you don't need to use the fine focus shaft.

Using the fine focus shaft just slows down your autofocus runs with no benefit that I can see.

[bottletopburly]

You can turn spindle around if required.

[DaveS]

2 hours ago, Robindonne said:

Kind of stupid that the design that allows manual-use, deletes the finefocusser, and the ones that dont allow manual-use, spare the finefocuser.  The perfect solution is probably on its way. 
But is it possible to turn the focusknobs around?  So the sesto senso still works but finefocus will be available? Or just mount that senso on the otherside, or mount the whole focusunit upsidedown?

maybe the motor is so weak that it needs the finefocus

You can get focusers that allow complete manual control and autofocus, but be prepared to pay for them

Optec Focuser

At bottom of page.

[Robindonne]

40 minutes ago, DaveS said:

You can get focusers that allow complete manual control and autofocus, but be prepared to pay for them

Ai thats not cheap.  But the €300,- senso does it also.  And i think the picture shows why the finefocus side is used.  They engineered it with the need of a part of the focusunit to attach their motorunit to, and the longer axel used by the fine knob that slides into their motorconnector

Edited May 9, 2020 by Robindonne

[DaveS]

The problem with the Sesto Senso is that if you move the focus by hand you then have to recalibrate, which is a pain. I think the Optec doesn't care.

[Robindonne]

Mm ok.  Then id better stop looking for this option.  When needing  the focuser i will probably always have power around the (powered) mount.  Although i cant understand why this small issue is so hard to solve, ill let it rest and focus on affordable focusers

[CraigT82]

Once you have used a motor focus you will never want to focus manually again!

[Robindonne]

20 minutes ago, CraigT82 said:

Once you have used a motor focus you will never want to focus manually again!

No i guess so.  I just thought of the moments i have now, when starting with eyepieces to do a staralignment etc and maybe some other visual use.  Dont know if its bothering for these short moments but ill have to find out. 

[CraigT82]

There are motor focusers that are battery powered, with batteries in the focuser handset. Hence not needing a laptop or anything. I have two, a skywatcher and a moonlight. They just stay permanently attached to the scopes and I dont do any manual focusing at all, for visual or imaging. 

[Robindonne]

1 hour ago, CraigT82 said:

There are motor focusers that are battery powered, with batteries in the focuser handset. Hence not needing a laptop or anything. I have two, a skywatcher and a moonlight. They just stay permanently attached to the scopes and I dont do any manual focusing at all, for visual or imaging. 

You’re right.  I checked the ones you described.  I believe It definitely works, but i have to buy all of these items for the first time and have to consider if also the battery powered ones are going to help me out when all these tools also have to be controlled by, in my case, an asiair v1, with probably some flaws but helping me get on the road fast and easy i hope.  

[Robindonne]

On 08/05/2020 at 19:15, Astrosharkey said:

Yep all correct

I bougth one recently for my sc (possible also newtonian with the right adapter) On the second hand market.   When inspecting it at home it was a big surprise to find out it does both electronic and manual focusing.  Havent used it yet but of course tried the both options.  It feels all okay, some sort of friction gear thing that lets you manual control the focuser while It has a permanent Belt connection with the focusmotor.   
 

Pics are from the advertisement but if you look good the shell V-power focuser can be identified.   Im sure the seller didn’t know about the manual focuser because he told me it was stuck😅

[Merlin66]

I use a similar SW motor/ belt drive on all my scopes - all six of them!!!

In my case I run the belt on the 10:1 knob for fine focus control (I only do solar observing and spectroscopy).