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Pegasus Dual Motor Focus Controller


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I have just set up the above Motor focus controller on the Altair Astro 72 ED . I have seen that the motor flexes on the bracket as it moves the focuser in and out . Is this to be expected  , or have I fitted the barrel to the focus knob wrong . I have no experience  of fitting these , just watched an instructional on youtube . Would be grateful for any advice. Many thanks....Alan.

 

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I have one of theses too, and they are superb,  make sure you tighten it to the focus shaft first, before you tighten the focus motor and bracket tight to the scope, that way it will centre itself, also have you use a flexible coupler if so then that will take any movement out of the equation, a picture may help, have you got one you could post.... :)

 

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46 minutes ago, SkyBound said:

I have one of theses too, and they are superb,  make sure you tighten it to the focus shaft first, before you tighten the focus motor and bracket tight to the scope, that way it will centre itself, also have you use a flexible coupler if so then that will take any movement out of the equation, a picture may help, have you got one you could post.... :)

 

Many thanks for such a quick reply. Because of the model of the scope I have had to attach focuser to the fine focus knob . Not able to fix the bracket on the coarse focus. Whether this is a problem...i dont know. Great advice earlier ....will redo it again Flexible coupler ? I have attached the one that came with the kit. Hope these photos help. Again big thanks.....any more tip most welcome.....Alan.

IMG_0363[1].JPG

IMG_0364[1].JPG

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Hmmmm, well these are powerful motors and should not really be fitted to the fine focus shaft.

now the reason for the flexing, because the hole in the flexible coupler that you are using is bigger than the fine focus shaft, when you tighten the grub screw it will push the shaft off centre very slightly, then when turning this will throw the motor assembly slightly off, the flexible coupler should take up this movement so should not be a problem.

you have used the correct coupler.. :)

so try and centre the shaft as best you can in the coupler hole, tighten the grub screws in turn a little at a time as this will help centre it.

but I think you will be ok, as long as it's not moving large amounts, but personally I would not be using on the fine focus shaft, it will also mean you have to move a lot of steps to see movement on it, as these motors have around 6000 steps per revolution of the coarse focus knob, so in the fine focus 10:1 this would be 60,000 steps to turn the coarse focus knob round once.

:)

Edited by SkyBound
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I have also just noticed the hole you are securing the motor bracket to is an access hole and should not be used for mounting.....and as you only have the one bolt, that is where some of the flex is coming from also, the whole thing is sticking out too far.

i think you need to re think this to be honest...!

why won't it fit on the other side, as I can't see the underside of the focuser to see your mounting options...

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1 hour ago, SkyBound said:

I have also just noticed the hole you are securing the motor bracket to is an access hole and should not be used for mounting.....and as you only have the one bolt, that is where some of the flex is coming from also, the whole thing is sticking out too far.

i think you need to re think this to be honest...!

why won't it fit on the other side, as I can't see the underside of the focuser to see your mounting options...

Many thanks for your  suggestions . I have re-centered the coupler and that works . as you have pointed out the gear side is far to slow . I will have to come up with a solution as you have suggested . On the other side  of the focuser there doesnt seem to be any options as there are no threaded holes........will ponder the problem .  will let you know of the outcome. Many thanks.....Alan.

 

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Looks like a pretty generic focuser the other knob should come off easily, you may need some stand off pillars to mount the bracket.

There's a post with a pic' somewhere, will have a look for it.

Dave :icon_santa:

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18 minutes ago, Astrith said:

Many thanks for your  suggestions . I have re-centered the coupler and that works . as you have pointed out the gear side is far to slow . I will have to come up with a solution as you have suggested . On the other side  of the focuser there doesnt seem to be any options as there are no threaded holes........will ponder the problem .  will let you know of the outcome. Many thanks.....Alan.

 

If you post a pic of the underside of the focuser you may find that some of the screws you can see are blanks and are just there to fill a hole that does not do anything, this is common on lots of focusers, then these screws can be removed and the holes used.... :)

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3 minutes ago, Davey-T said:

I would cut the bracket around the locking screw.

If you're into DIY I'd fabricate a custom bracket out of something thicker

Dave

Not a DIY er but yes I see what you mean . Still pondering and many thanks .....Alan

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3 minutes ago, Nova2000 said:

Which scope is that Dave? And which focuser? 

Not mine, it's in the scopes bit of the forum about a week ago in a post by Steppenwolf if you do a search.

Dave

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29 minutes ago, Davey-T said:

I've  got some odds and ends of ally, if you PM me some measurements I'll knock you up a bracket.

Dave

Thats very kind of you Dave . I will attempt to do some measurements . Many thanks.

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  • 2 weeks later...
On 12/21/2016 at 14:13, Astrith said:

Thats very kind of you Dave . I will attempt to do some measurements . Many thanks.

Dave .

Hello Dave . Ive just sorted out the focuser . I have modified the backing plate and its working well . Again many thanks for the offer. Cheers....Alan.

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  • 1 month later...

Just to follow up on this, I have just got one of these and fitted it on my TS80 and yes, the bracket flexes quite a bit, to the point that I am replacing it today with a better one.

It appears that to make the system as "generic" as possible, and to fit as may focusers as possible, they have made the bracket slots full length which has taken the meat out of it and allows it to twist laterally.  Mine is mounted under the focuser, quite close in and with 2 fixing screws, but even so I am still seeing a "backlash" (which is actually the mount bracket twisting and not actual backlash) of around 100 steps, which is waaaay too much.  It is a brand new OTA though, so the focuser is probably a little tighter than one been used for a while, so in this instance that may not be helping.

The focus controller and motor etc. are excellent though, and work perfectly with SGPro, so it's definitely a keeper.

Maybe the manufacturer should look at this as a standard kit, but also offer custom brackets for the best known focusers, which would solve a lot of issues on an otherwise really good piece of kit for the money.

I've gone for the Lakeside from Ian King on my Esprit 100, which has a custom made bracket supplied by them.

Edited by RayD
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Tinkering and DIY is mandatory in this hobby ? My custom made bracket for my lakeside had to have an additional hole drilled for the focus lock and I had to countersink the two attachment holes so the provided screws could reach. But got it attached to my TEC 140 nicely. Will power it up tomorrow hopefully.

Edited by kirkster501
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57 minutes ago, kirkster501 said:

Tinkering and DIY is mandatory in this hobby ? My custom made bracket for my lakeside had to have an additional hole drilled for the focus lock and I had to countersink the two attachment holes so the provided screws could reach. But got it attached to my TEC 140 nicely. Will power it up tomorrow hopefully.

Oh I've definitely learnt that already ?

My Lakeside has a custom bracket already from Ian King, which is excellent, and the one I'm making for the pegasus is actually pretty similar.

Lakeside is good, got mine all up and running today and pretty impressed with it.

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