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Vixen SDX2 visual load limit

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#1 ScottW

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Posted 15 May 2021 - 07:27 AM

Hi,

I would like to know ir a SDX2 with D type mounting can handle a F#* reflector of just under 40lbs for visual use. Would it be too much or shake too much when touched?

 

Thanks,

Scott



#2 dUbeni

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Posted 15 May 2021 - 08:21 AM

Hello Scott, I don't know the exact answer to that. I do load my 28lb 8" f/4 reflector, including rotating rings, coma corrector, heavy eyepiece, etc. and it works fine.

Vixen states in the manual that maximum load for astrophotography is 33lb (375kg*cm torque load at 25cm from fulcrum). At 40lb I wouldn't go that route without trying it first. My experience with mounts is that it's always better to be below weight limit specs. I compare them to cars, I don't drive at full speed it will ware them down very fast.

My bet is that you will see some shake even if you have an excellent tripod.

 

Sincerely

Bernardo



#3 teashea  Happy Birthday!

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Posted 15 May 2021 - 09:35 PM

187187766_10222211059199810_8903683398579780622_n.jpg

Hi,

I would like to know ir a SDX2 with D type mounting can handle a F#* reflector of just under 40lbs for visual use. Would it be too much or shake too much when touched?

 

Thanks,

Scott

I have two SDX2's.  My answer to your question is absolutely not.  Not even close.  This mount was not designed for that kind of weight.  I am also a visual observer and would not put more than 15 pounds on an SDX2.  

 

 



#4 teashea  Happy Birthday!

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Posted 15 May 2021 - 09:39 PM

Undermounting a telescope is, unfortunately, a very common thing.  The mount is as important as the telescope.  For the best results, it must be a rock.



#5 alan.dang

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Posted 15 May 2021 - 10:02 PM

attachicon.gif187187766_10222211059199810_8903683398579780622_n.jpg

I have two SDX2's.  My answer to your question is absolutely not.  Not even close.  This mount was not designed for that kind of weight.  I am also a visual observer and would not put more than 15 pounds on an SDX2.  

Agree that 40 lbs is pushing it, but the SXD2 will punch above its weight.  Here is 20 lbs imaging with an Astro Physics 130mm EDF under windy conditions.

 

The tripod is probably the weakest point in terms of vibrations. 

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#6 kevinmat

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Posted 15 May 2021 - 10:03 PM

I think that most SDX2 owners would not have a problem putting 25-30lbs on the mount for visual as long as its well balanced, 40lbs would really be pushing it.



#7 payner

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Posted 16 May 2021 - 01:05 AM

Vixen Japan (https://global.vixen...roduct/25101_8/) lists the loading weight at 33 lbs with specific torque rating. For visual, I load 40 lbs and it doesn't tax the mount at all. The critical point here is to make sure you properly balance your load. There is no arguing the HAL 130 tripod is adequate, and lightweight for its performance, but is the weak link when putting heavier loads than about 25 lbs on the mount. There are a number of great tripods that really take this mount to another level performance-wise.

 

Randy



#8 dUbeni

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Posted 16 May 2021 - 05:54 AM

Hi payner, just out of curiosity how much counter-weight do you need for a 40lb load?

I agree with you on the tripod, for a 40lb load it certainly needs a sturdy tripod.

 

Bernardo



#9 Blueox4

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Posted 16 May 2021 - 07:43 AM

40# might be pushing it. When I had my SXD2 mounting my APM130 f/9 refractor fully dressed weighing in at 24-25 lbs. it felt pretty stable and worked well. Another 15lbs would have been too much for me. Just my experience. Good luck! 



#10 kevinmat

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Posted 16 May 2021 - 08:36 AM

The HAL tripod is certainly the weak link in the system, hence the reason I have been contemplating a Berlebach Uni 28 to replace it



#11 payner

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Posted 16 May 2021 - 10:30 AM

If at about 40 lbs (and I typically use another mount for this load) I use 16 to 20 lbs CW. As to the comment about a 130/1200, I had one years ago. I too mounted it successfully and stably. The reason why you (or I) would not want to go much heavier with such an instrument is due to the moment arm (torque) required for long OTAs such as the 130/1200.

 

Now the mount I was referring to was the SXD; I sold it. I now have the SXD2, but the general specs such as capacity remains essentially the same between the two. Get a commensurate tripod, e.g. the Berlebach Planet, and you might be surprised at the result. And I'm certainly not talking about taxing the mount beyond recommendation.



#12 teashea  Happy Birthday!

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Posted 16 May 2021 - 08:13 PM

It is interesting how many people are content to undermount their telescopoes.



#13 marcus_z

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Posted 17 May 2021 - 12:25 PM

The manual of the SXD2 shows counterweight configurations up to 32 lbs instrument weight with a distance of 25cm to the axis. So don't even think about the SXD2 for this type of instrument 😉
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#14 Deadlake

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Posted 18 May 2021 - 08:52 AM

The SXP2 can take 20.5 kg (45 lbs) for visual use, you will need to step up to larger mount.

How long is the scope, it's really how much torque the mount needs to generate? 


Edited by Deadlake, 18 May 2021 - 12:01 PM.


#15 JuergenB

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Posted 18 May 2021 - 09:08 AM

It is interesting how many people are content to undermount their telescopoes.

That's true. I never could stand shaky and wobbly mounts. The mount in our school observatory which I liked most in terms of stability was a twin of that one made by Wachter (Germany) for our 9" Coudé refractor with Lichtenknecker (Belgium) optics:

 

Wachter mount.jpg

 

(Source: Wachter advertisement)

 

Juergen




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