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increase in stability in replacing dovetail alone?

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#1 jmillsbss

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Posted 28 June 2022 - 09:36 AM

Just a thought exercise at first, and not a very strenuous exercise at that, but I've been curious about the purpose of the wider Losmandy based size attachment hardware and why, other than to be different?

 

I doubt very seriously the Losmandy was made wider than the Vixen standard width dovetail/saddle just to be different.  It's far less expensive to use existing hardware standards than to break out with exclusive sizes when the majority of your potential market already has a significant amount of universal equipment already.

 

Some of the earlier mounts I had, CG1/CG2/EQ1 types, had no saddle/dovetail arrangement, but rather a specifically odd device that your tube rings screwed into.  Perhaps the Vixen guys made the dovetail to simplify and universalize the systems so AA could use multiple OTAs/mount combos?

 

I know there are "narrow to wide" and "wide to narrow" adapters, and that's probably just for what it says, as an adapter.  But what about an increase in stability?  Let's say a guy like me really has about maxxed out a particular OTA/mount combination.

 

Would it be of any help to swap out the Vixen rail on the OTA with a Losmandy-width dovetail and simply use a narrow to wide adapter?  Would it stabilize the setup any at all?  My speculation is the best result would be maybe negligible.  I may be wrong but someone somewhere has surely done this.  And I understand the issue here is payload weight, but I'm curious about the mount interface.

 

Further, would it add any stability to replace BOTH the dovetail AND the saddle with the wider Losmandy width hardware?

 

Is it noticeable or negligible?    Thanks for responding!  Jay

 

EDIT:  I know the first response is gonna be "Upsize your mount!" or something to do with weight capacity, and those comments are understood....I'm just thinking about the "why" and would it help? of the different size mount/OTA hardware.

 



#2 weis14

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Posted 28 June 2022 - 10:13 AM

In the "old days" (i.e. 80s and 90s) almost every mount manufacturer introduced their own dovetail systems.  Vixen and Losmandy were the first, but Astro-Physics, Half Hitch and others had competing designs.  It was only after a number of years and remarketing of Vixen and Losmandy mounts by Celestron and others that these two became the standard for small and medium sized scopes.  (I think that a C11 is probably as big as I'd want to go on either system).      

 

In general, the wider Losmandy dovetails should be more stable, especially if the dovetails are long.  I tend to favor the Losmandy system for any scopes over 4-6" in diameter.  However, this depends a lot on the quality and size of the dovetails themselves and you can buy a weak Losmandy dovetail or a robust Vixen one.  

 

 

Would it be of any help to swap out the Vixen rail on the OTA with a Losmandy-width dovetail and simply use a narrow to wide adapter?  Would it stabilize the setup any at all?  My speculation is the best result would be maybe negligible.  I may be wrong but someone somewhere has surely done this.  And I understand the issue here is payload weight, but I'm curious about the mount interface.

 

I don't think this would help and it would probably hurt.  By using an adapter between the mount and the scope, you are introducing another element that could induce vibration or flexure.  That said, I've done it with my Half Hitch mounts and didn't notice any issues visually.  If you want to try it, I think a better approach would be to replace the saddle on your mount with a dual Vixen/Losmandy saddle from ADM or elsewhere and test it that way.  I have used dual saddles on multiple mounts.



#3 jmillsbss

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Posted 28 June 2022 - 11:07 AM

In the "old days" (i.e. 80s and 90s) almost every mount manufacturer introduced their own dovetail systems.  Vixen and Losmandy were the first, but Astro-Physics, Half Hitch and others had competing designs.  It was only after a number of years and remarketing of Vixen and Losmandy mounts by Celestron and others that these two became the standard for small and medium sized scopes.  (I think that a C11 is probably as big as I'd want to go on either system).      

 

In general, the wider Losmandy dovetails should be more stable, especially if the dovetails are long.  I tend to favor the Losmandy system for any scopes over 4-6" in diameter.  However, this depends a lot on the quality and size of the dovetails themselves and you can buy a weak Losmandy dovetail or a robust Vixen one.  

 

 

 

I don't think this would help and it would probably hurt.  By using an adapter between the mount and the scope, you are introducing another element that could induce vibration or flexure.  That said, I've done it with my Half Hitch mounts and didn't notice any issues visually.  If you want to try it, I think a better approach would be to replace the saddle on your mount with a dual Vixen/Losmandy saddle from ADM or elsewhere and test it that way.  I have used dual saddles on multiple mounts.

 

In the "old days" (i.e. 80s and 90s) almost every mount manufacturer introduced their own dovetail systems.  Vixen and Losmandy were the first, but Astro-Physics, Half Hitch and others had competing designs.  It was only after a number of years and remarketing of Vixen and Losmandy mounts by Celestron and others that these two became the standard for small and medium sized scopes.  (I think that a C11 is probably as big as I'd want to go on either system).      

 

In general, the wider Losmandy dovetails should be more stable, especially if the dovetails are long.  I tend to favor the Losmandy system for any scopes over 4-6" in diameter.  However, this depends a lot on the quality and size of the dovetails themselves and you can buy a weak Losmandy dovetail or a robust Vixen one.  

 

 

 

I don't think this would help and it would probably hurt.  By using an adapter between the mount and the scope, you are introducing another element that could induce vibration or flexure.  That said, I've done it with my Half Hitch mounts and didn't notice any issues visually.  If you want to try it, I think a better approach would be to replace the saddle on your mount with a dual Vixen/Losmandy saddle from ADM or elsewhere and test it that way.  I have used dual saddles on multiple mounts.

If anything were to be switched, I would think the adapter would be the weakest link and likely the least effective, if effective at all, in helping to stabilize the scope.  That's just based on speculation, of course.  That's why I asked the forum, as all I can do is sit here and speculate.  I feel like the best chance at an improvement would be to replace both dovetail and saddle to a quality Losmandy-size setup.  Like you, I would also think the longer the better regarding length of saddle and bar.


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#4 Sacred Heart

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Posted 28 June 2022 - 01:31 PM

Without knowing the scope or mount,  it would be best to have your saddle as long or longer than your dovetail plate. Within reason.  If your dovetail plate is 10"  to 14" long I would want atleast a 8 inch saddle.   Definitely not a 3" or 4" saddle for a 10 - 20 pound scope.     Having your saddle match up to your dovetail plate in length better takes flexure out of it a little more but adds weight so now the mounts drive motors have to work harder.  It is truly a total system thing.    Joe



#5 jmillsbss

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Posted 28 June 2022 - 03:26 PM

Without knowing the scope or mount,  it would be best to have your saddle as long or longer than your dovetail plate. Within reason.  If your dovetail plate is 10"  to 14" long I would want atleast a 8 inch saddle.   Definitely not a 3" or 4" saddle for a 10 - 20 pound scope.     Having your saddle match up to your dovetail plate in length better takes flexure out of it a little more but adds weight so now the mounts drive motors have to work harder.  It is truly a total system thing.    Joe

My mounts are light medium at best and all have the 3 or 4 inch OEM saddle.  Just putting a 10" bar on the C8 is great for balancing, but it never seems like that is enough to hold the weight.

 

1.  The mount needs to be redundant in weight capacity.

2.  The OTA has to be balanced in the mount.

3.  The more contact between the mount and OTA, the better.



#6 Sacred Heart

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Posted 28 June 2022 - 04:03 PM

My mounts are light medium at best and all have the 3 or 4 inch OEM saddle.  Just putting a 10" bar on the C8 is great for balancing, but it never seems like that is enough to hold the weight.

 

1.  The mount needs to be redundant in weight capacity.

2.  The OTA has to be balanced in the mount.

3.  The more contact between the mount and OTA, the better.

Is there a larger saddle plate for it??   8" saddle??    Joe



#7 fmendes

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Posted 30 June 2022 - 12:25 PM

This is an interesting topic. I own a Sky Watcher Quattro 200mm that has a Vixen bar, and was considering change the bar to a Losmandy. However, the telescope ring is about the same width as the bar, so it would still be a point of flexion. By curiosity I went to the Sky Watcher page, and saw that even their Quattro 250mm (weight 36.5 lb, 16.5 Kg) uses Vixen. Only the 300mm (57 lb, 26 kg) uses Losmandy, and has matching rings.




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