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Fitting a Baader Quick Lock to my Orion ST120 Focus barrel.

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#1 Andrew Simpson

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Posted 08 February 2018 - 02:59 PM

Can anybody here be kind enough to tell me what kind of threads are exposed when the thumb screw collar is removed from the 2" focus barrel. of my Orian ST120. They are male threads OD 55.68mm, threaded end, and inner is the smooth 2" bore. I need to know if this is considered M54 thread so I will know which 2" Baader quick lock clamp to use that will replace the original screw on collar. 



#2 photoracer18

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Posted 08 February 2018 - 03:56 PM

When they say things like M54 they mean 54mm plus or minus a very tiny amount if any at all. The only M-metric sizes I have dealt with are exactly on the number, like M42 (Pentax screw-mount and Tamron T-ring although each has different thread pitch), M37 Leica camera lens thread). There is no variation except when its based on an English measurement like 2" which is 50.8mm. M54 would not be 55.68mm if that is an accurate measurement (55.68mm = 2.192"). You need to find the Baader adapter for your particular focuser. Since its an Orion its likely a Synta brand focuser.


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#3 junomike

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Posted 08 February 2018 - 04:25 PM

I believe It's this one.


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#4 Agatha

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Posted 08 February 2018 - 04:38 PM

Yes, agree with Mike above.  


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#5 nicoledoula

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Posted 09 February 2018 - 06:30 PM

Anyone know if this one https://agenaastro.c...56-2956256.html fits the ES AR 102mm? 



#6 Andrew Simpson

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Posted 10 February 2018 - 12:32 AM

 There is no variation except when its based on an English measurement like 2" which is 50.8mm. M54 would not be 55.68mm if that is an accurate measurement (55.68mm = 2.192"). 

 

 

One thing I forgot to mention is the focuser is the 2 speed upgrade that Orion carries but the barrel measures the same as the original. 

 

Focuser being this. 

 

https://www.telescop...2 speed focuser

 

The 55.68 was the measurement I got with digital vernier calipers placed on the outer diameter of the threaded portion of the focuser barrel. With the inner diameter being 2" or 50.8mm , so splitting difference "sort of" was my best guess of M54 based on the choices at Highpoint Scientific.

 

https://www.highpoin...hread-clskywn-2

 

However as junomike suggest, the Baader M56 model that HS didn't have listed seems to be the best bet. 

 

I contacted HS and they didn't have compatibility information unless I  knew the thread size. So I contacted Orion and their response was..

 

"The Orion 2" dual speed crayford focuser. is built to leave the 2" ring on the focuser. We have never measured that threads. But these threads only match the the .85 focal reducer for the 80mm ED. (5195) as the dual speed was built to replace the single speed in the 80mm."

 

So looks like I must be the first in the history of telescope accessorizing to want to fit a Baader Quicklock to an Orion ST120

 

Anyway, looks like the thing to do is try the M56. 

 

Thanks for the help.


Edited by Andrew Simpson, 10 February 2018 - 12:33 AM.


#7 Andrew Simpson

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Posted 10 February 2018 - 12:39 AM

Anyone know if this one https://agenaastro.c...56-2956256.html fits the ES AR 102mm? 

 I replied back to Highpoint Scientific after not getting anywhere with Orion and they provided me with this. 

 

"You can contact Bob Luffel over at Alpine Astronomical (the Baader distributor in the US) at (208)-939-2141 . I am not sure if he is going to have the information that you are looking for but it is worth a try!"



#8 MGD

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Posted 10 February 2018 - 03:56 AM

Read the description for the m56 click lock on Agena that Mike linked all the way to the bottom. It specifically says it fits the focuser for the orion 80ed focuser. Orion told you the focuser you have is for the 80ed so it's the m56 version. The m54 version only applies if it was the original st120 focuser. Hope this helps.

Mike 


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#9 Andrew Simpson

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Posted 10 February 2018 - 12:01 PM

Read the description for the m56 click lock on Agena that Mike linked all the way to the bottom. It specifically says it fits the focuser for the orion 80ed focuser. Orion told you the focuser you have is for the 80ed so it's the m56 version. The m54 version only applies if it was the original st120 focuser. Hope this helps.

Mike 

Yea, I did happen to notice that little foot note last night. Looks like the M56 is the one to go with. waytogo.gif

I wish  every scope manufacture would list all thread sizes as part of an exploded view like many other products do. tongue2.gif



#10 Andrew Simpson

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Posted 17 February 2018 - 04:45 PM

I believe It's this one.

I ordered this one, for M56 thread and it did indeed fit. 

 

waytogo.gif waytogo.gif waytogo.gif




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