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Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 4:54 am
by DeanD
Hi Folks,

I am considering getting a replacement GSO 10:1 crayford focuser for my Celestron XLT 150mm f5 achromat, but one issue is that the stock focuser has a built-in attachment point for the shoe of the finder scope. The GSO replacement doesn't, and there is no other easy spot to attach the finder on the scope. I could make an attachment to sit it on the mount brackets, but this is a pain if I want to rotate the tube (eg: when I attach the scope by the side to my M2 or iOptron alt-az mounts).

So, I am just wondering if anyone out there has done something like this with a focuser replacement, and what you did for the finder? I am thinking of getting a red-dot finder of some sort instead of the 8x50 straight-through one that came with the scope.

All thoughts gratefully accepted!

Thanks,

Dean

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 8:04 am
by John Baars
Hi Dean,
My f/5 came with an extra dovetail-bar. I put in some extra nuts so I could use it as a handle -bar. Furthermore I drilled and tapped two extra holes to install a Telrad base on it. The Telrad works fine, but any other RDF will do of course. Problem stays that it won't rotate.
IMG_1263 (640x480).jpg
For rotation one must attach a finder-base to the telescope itself or to the focusser. I am not in need of this, but lately I found out, while working on the further blackening of the inside-focusser, there is more than enough room for drilling and tapping two extra M5 or M6 holes. Or even a M5 nut on the inside, in case you have no M5 taps.
IMG_1265 (640x480).jpg

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 8:15 am
by Lady Fraktor
As well as John two examples there is also bolting it directly to the tube in front of the focuser flange.

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 2:17 pm
by mariosi
20190707_095830.jpg
IMG-d1f93ead051936a78fe0eff768b09895-V.jpg

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 2:53 pm
by Don Alvarez
DeanD wrote: Wed Nov 06, 2019 4:54 amSo, I am just wondering if anyone out there has done something like this with a focuser replacement, and what you did for the finder? I am thinking of getting a red-dot finder of some sort instead of the 8x50 straight-through one that came with the scope.
I have replaced two focusers with GSO units. There is a finder shoe made for them:

https://agenaastro.com/agena-finder-mou ... users.html

No modifications required. Single screw to install and the "rails" on the bottom of the shoe make sure it is lined up in the right direction. I use RACI's on these, so a red dot should be no issue.

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 3:37 pm
by Don Quixote
mariosi wrote: Wed Nov 06, 2019 2:17 pm 20190707_095830.jpg

IMG-d1f93ead051936a78fe0eff768b09895-V.jpg
Very nice Mariosi !
Thank you for imaging this here.

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 8:45 pm
by Bigzmey
I had regular and linear bearing GSO Crayford focusers on my 150ST. You can attached finder base via single screw to both. I will snap some pics.

Here is the base I use.

https://www.ebay.com/itm/Multi-Function ... SwXaRaBrRh

Re: Finder attachment for 150mm f5?

Posted: Wed Nov 06, 2019 10:15 pm
by DeanD
Thanks to all for responding. It is always great to get other peoples' ideas: sometimes you just miss the obvious! :)

I was procrastinating about getting the focuser, but you have encouraged me (don't tell the finance department though! ;) )

Thanks again, and all the best,

Dean

Re: Finder attachment for 150mm f5?

Posted: Thu Nov 07, 2019 12:57 am
by Doug James
Keep use updated with what you end up doing with the upgrade to your 150mm. Good post, thanks

Re: Finder attachment for 150mm f5?

Posted: Thu Nov 07, 2019 3:35 pm
by Don Alvarez
DeanD wrote: Wed Nov 06, 2019 10:15 pm Thanks to all for responding. It is always great to get other peoples' ideas: sometimes you just miss the obvious! :)

I was procrastinating about getting the focuser, but you have encouraged me (don't tell the finance department though! ;) )

Thanks again, and all the best,

Dean
It is a good upgrade to do. The GSO focuser is muuuuuuch nicer than factory rack and pinion ones.

I might actually prefer the shoe that Bigz linked. The slots will let you center the screw better than the GSO shoe.

Re: Finder attachment for 150mm f5?

Posted: Thu Nov 07, 2019 7:36 pm
by Bigzmey
Don Alvarez wrote: Thu Nov 07, 2019 3:35 pm
DeanD wrote: Wed Nov 06, 2019 10:15 pm Thanks to all for responding. It is always great to get other peoples' ideas: sometimes you just miss the obvious! :)

I was procrastinating about getting the focuser, but you have encouraged me (don't tell the finance department though! ;) )

Thanks again, and all the best,

Dean
It is a good upgrade to do. The GSO focuser is muuuuuuch nicer than factory rack and pinion ones.

I might actually prefer the shoe that Bigz linked. The slots will let you center the screw better than the GSO shoe.
I prefer this cross slot shoe design over the others. It fits all my scopes from 8" SCT and 150ST to 127mm Mak and 80mm ED perfectly.

Re: Finder attachment for 150mm f5?

Posted: Fri Nov 08, 2019 12:24 am
by DeanD
Bigzmey wrote: Thu Nov 07, 2019 7:36 pm
Don Alvarez wrote: Thu Nov 07, 2019 3:35 pm
DeanD wrote: Wed Nov 06, 2019 10:15 pm Thanks to all for responding. It is always great to get other peoples' ideas: sometimes you just miss the obvious! :)

I was procrastinating about getting the focuser, but you have encouraged me (don't tell the finance department though! ;) )

Thanks again, and all the best,

Dean
It is a good upgrade to do. The GSO focuser is muuuuuuch nicer than factory rack and pinion ones.

I might actually prefer the shoe that Bigz linked. The slots will let you center the screw better than the GSO shoe.
I prefer this cross slot shoe design over the others. It fits all my scopes from 8" SCT and 150ST to 127mm Mak and 80mm ED perfectly.
I have ordered one, thanks! Hopefully it will arrive quicker than my last order from China. I am still waiting on that one from February!

I am undecided about the finder itself. I will wait until I have attached the new focuser: which should arrive on Monday.

Thanks again folks.

Re: Finder attachment for 150mm f5?

Posted: Sun Nov 10, 2019 6:13 am
by OzEclipse
DeanD wrote: Fri Nov 08, 2019 12:24 am
I have ordered one, thanks! Hopefully it will arrive quicker than my last order from China. I am still waiting on that one from February!
I ordered some large format film from Teds Camera store in October. Still waiting. Have since sold the large format camera. Converted to digital cameras. So hoping they don't call up to say my order has arrived. I'm not worried.

..........it wasn't October 2019, it was October 1997 :lol: :lol: :lol: :lol:

Joe