SW 130PDS + GPU direct connection

[RolandKol]

Hi guys,

Does anyone knows which connectors/adaptors are needed to attach GPU Coma Corrector directly to PDS focuser (EFW + ASI1600 will sit on it)?

That default wobbly eyepiece holder is simply making me mad.

I do look for a bit larger and a bit better scope, but if direct connection is not too expensive, - why not...

P.S.

Connection most likely should not add any additional length as GPU focus point is almost at the very end of Drawtube even if the primary mirror is pushed as far away from focuser as possible.

Edited October 16, 2022 by RolandKol

[Stefan73]

22 hours ago, RolandKol said:

Does anyone knows which connectors/adaptors are needed to attach GPU Coma Corrector directly to PDS focuser (EFW + ASI1600 will sit on it)?

That default wobbly eyepiece holder is simply making me mad.

I'm not sure you could directly attach a GPU coma corrector (at least mine wouldn't) as they seem to be designed to be used as a nose piece. 

Maybe something like https://www.firstlightoptics.com/adapters/astro-essentials-2-inch-compression-ring-adapter-for-sky-watcher-newtonians-and-72ed-refractor-m54.html or https://www.firstlightoptics.com/adapters/baader-2-clicklock-m54-clamp.html would make it less wobbly though?

23 hours ago, RolandKol said:

Connection most likely should not add any additional length as GPU focus point is almost at the very end of Drawtube even if the primary mirror is pushed as far away from focuser as possible

Do you mean the draw tube needs nearly maximum extension to reach focus?  My existing PDS adapter measures about 12mm. The first claims an optical distance of 10mm and the second 30mm so I guess using the second would enable the draw tube to be in further to reach focus.  Or you could presumably use the first with some spacers.

[RolandKol]

Baader Clickclock does not match for 130PDS as is too long, - at least I was advised so.

as per compression ring, - I do have it... sadly... And I do not like it at all, - still lots of place for tilt and etc... Better than default, but not what I want.

FLO advised to get this one https://www.teleskop-express.de/shop/product_info.php/language/en/info/p4041_TS-Optics-Adapter-von-M48---2--Filtergewinde-auf-M54x0-75-Gewinde.html

But goodness... price with delivery will be almost £40... 

Thinking if this alternative will match https://www.rothervalleyoptics.co.uk/rvo-m54-male-to-m48-female-adaptor.html ~£20 , I guess I will give a try.

 

1 hour ago, Stefan73 said:

Do you mean the draw tube needs nearly maximum extension to reach focus?  

Yes, and even a bit more... If primary mirror is pushed IN during collimation, there is a chance focus will not be reached, - depends on filters or imaging devise.... I moved my primary mirror Back as Much as possible and collimated at that point... 
while been typing all of that... It seems, the longer the drawtube, or the further it will get extended... the better in my case...

P.S.

just found this one. for £9.. It looks like it also may match GPU https://www.ebay.co.uk/itm/224687317170?hash=item34506860b2:g:efYAAOSwnLVhjO-t&amdata=enc%3AAQAHAAAA4C1%2BsYgnvooS8mYYHIsWRKjf1uOOUvbLW44smnwmzZTxqV8yz7DJyMyDHMwdIKMe8ddwf%2FigChRc9fonOV3bvWuGuBYtVz9sttyPADSSmG5RScW%2Bs5FJQ1%2Faxv4RK9yTWiJLZRBRlMsffeFXhLdENtuw1AYVz3mSjN4YZlUz9gJE27yDyp%2FmDWRBg7XPEvNvaIrgNTvZVWfgdD0OWSxvu%2F31VOqMuVfCLn1DLVtwwCOLzBmlVw1q8GFON2xNSp%2BVqgSvZTYpWOH6B72csJSSSCSj1TyJL1mx7HOV%2BZuapmTO|tkp%3ABFBMwMGY7_xg

[Stefan73]

1 hour ago, RolandKol said:

Baader Clickclock does not match for 130PDS as is too long, - at least I was advised so.

as per compression ring, - I do have it... sadly... And I do not like it at all, - still lots of place for tilt and etc... Better than default, but not what I want.

FLO advised to get this one https://www.teleskop-express.de/shop/product_info.php/language/en/info/p4041_TS-Optics-Adapter-von-M48---2--Filtergewinde-auf-M54x0-75-Gewinde.html

You must have a very different CC to me.  I use this one from FLO https://www.firstlightoptics.com/coma-correctors/ts-10x-gpu-superflat-4-element-2-coma-corrector.html and I can't see any M48 thread on the telescope side, just on the camera side.  The telescope side looks just like a smooth nose piece.

The Bader one might work on 130PDS if you're CC moves the focus position outwards like the one I linked, otherwise you're right there wouldn't be enough inward travel.  Easy enough to measure if you've got 30mm and there's always FLO's returns policy...

 

[RolandKol]

4 minutes ago, Stefan73 said:

You must have a very different CC to me.  I use this one from FLO https://www.firstlightoptics.com/coma-correctors/ts-10x-gpu-superflat-4-element-2-coma-corrector.html and I can't see any M48 thread on the telescope side, just on the camera side.  The telescope side looks just like a smooth nose piece.

The Bader one might work on 130PDS if you're CC moves the focus position outwards like the one I linked, otherwise you're right there wouldn't be enough inward travel.  Easy enough to measure if you've got 30mm and there's always FLO's returns policy...

 

Actually, the same, just read the description once again, btw, TS has a bit better one.

"With optional adapters you can screw the corrector to the drawer. For this purpose the corrector has an extended M48x0.75 thread on the camera side. Simply turn down the lock ring and you have 3 mm more M48 thread for screw adaptations available."

Teleskop-Express: TS-Optics NEWTON Coma Corrector 1.0x TSGPU Superflat - 4-element - 2" connection

[Stefan73]

25 minutes ago, RolandKol said:

"With optional adapters you can screw the corrector to the drawer. For this purpose the corrector has an extended M48x0.75 thread on the camera side. Simply turn down the lock ring and you have 3 mm more M48 thread for screw adaptations available."

Ahh the penny drops! I'd never realised it could do that.