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Mount loading


Patbloke

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Here's a thing, I have a beautiful condition AVX and have been looking at the amount of weight she will take.... 30lbs 13.6kg (although there was a view 35lbs from somewhere I read)

I just weighed my 150 Frac and without EP, Diagonal and Telrad it's coming up 9.8kg ... that leaves me 3.8kg for counterweight mmm

I take it the load of the mount is scope plus counterweights?

 

I think I might need a bigger boat????

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I used to use one of those 6" F/8 fracs for visual on a Celestron CG5 and it was OK. I'd have thought that the AVX would be just a bit better than that. It's close if not equal to the capacity of the HEQ5 from what I can see of the specs and plenty of folks run 6" F/8 fracs on those for visual.

 

 

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Here's your weights and dimensions for the AVX mount:

  • Carrying capacity 14kg (30lbs) (not including counterweights)
  • Tripod Weight 8kg (18lbs)
  • Mount Weight 7.7kg (17lbs)
  • Counterweight 5.5kg (12lbs) x 1
  • Total Weight: 20.7kg (46lbs)
  • Mount Height: 40.6cm (16")
  • Tripod Height: 74-127cm (29-50")
  • Tripod Legs Outside Diameter 50mm (2") and 38mm (1.5")

Hth :)

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3 minutes ago, brantuk said:

Here's your weights and dimensions for the AVX mount:

  • Carrying capacity 14kg (30lbs) (not including counterweights)
  • Tripod Weight 8kg (18lbs)
  • Mount Weight 7.7kg (17lbs)
  • Counterweight 5.5kg (12lbs) x 1
  • Total Weight: 20.7kg (46lbs)
  • Mount Height: 40.6cm (16")
  • Tripod Height: 74-127cm (29-50")
  • Tripod Legs Outside Diameter 50mm (2") and 38mm (1.5")

Hth :)

Great work thanks very much for taking the time everyone...

I have not been getting out much lately due to poor weather and the usual problem of not having a garden, but when I do; I default to my lovely 102 on the AVX which seems a perfect mate... 

However, inspired by Nick (the guy with the small boat above) I want to use my refurbished 150 to do some serious binary splitting :-)

 

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As much as I love my AVX with my 100ED, it's just not coping with my 12kg 6" frac. As hard as I tighten the clutches it still slips and I lose goto alignment. A shame as up until now it's been a fantastic mount and I hate to post a negative comment.

Do post and let us know how you get on.

Regards,

Tom.

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The weight business is (to persue the fish theme :D)  largely a load of codswallop. It is really about  things like damping time (imagers can't wait for it but visual observers can) and tracking accuracy (imagers need it and observers don't.)  I think the best thing for anyone in doubt to ask is, 'Anyone out there using this scope on that mount to do this job?'

Olly

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I think it was Olly that mentioned the analogy of trying to write with a short pen then with the pen on the end of a foot long stick, the maximum load tells you little the moment of inertia of a long tube is far more critical than its weight.

Alan 

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On 23 August 2016 at 20:12, ollypenrice said:

The weight business is (to persue the fish theme :D)  largely a load of codswallop. It is really about  things like damping time (imagers can't wait for it but visual observers can) and tracking accuracy (imagers need it and observers don't.)  I think the best thing for anyone in doubt to ask is, 'Anyone out there using this scope on that mount to do this job?'

Olly

Absolutely. Indeed, I've found that the dampening times are acceptable when using the 6" refractor on the AVX. 

I was simply making the point that I've found that the mount won't track reliably with this load - the goto's start off okay but worsen significantly as the evening goes on, no matter how carefully balanced the scope is and how accurately the mount is initially aligned. I don't experience this issue with a lighter load. Unless I'm doing something wrong, which is always a possibility :).

We could argue that accurate goto's are not really essential, but they are one if the reasons why I bought the mount in the first place.

Regards,

Tom

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It's hard to see why the extra weight would induce drift in the system over time, though I take your word for it that it does. It couldn't be something as simple as the tripod sinking into the ground or the legs slipping a little? Or the clutches not gripping perfectly?

I like GoTo systems which can be painlessly 'updated' simply by going to a star near the target and re-synching. This can be more or less straightforward depending on the system. And, yes, GoTo should go to. That's why it's there!

Olly

Edit: Just anther thought. If your heavier rig has a longer focal length then GoTo will need to be better in accordance with the reduced field of view.

 

 

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4 minutes ago, ollypenrice said:

It's hard to see why the extra weight would induce drift in the system over time, though I take your word for it that it does. It couldn't be something as simple as the tripod sinking into the ground or the legs slipping a little? Or the clutches not gripping perfectly?

I like GoTo systems which can be painlessly 'updated' simply by going to a star near the target and re-synching. This can be more or less straightforward depending on the system. And, yes, GoTo should go to. That's why it's there!

Olly

Edit: Just anther thought. If your heavier rig has a longer focal length then GoTo will need to be better in accordance with the reduced field of view.

 

 

Thanks Olly. I think it's that the weight is too much for the clutches. No matter how hard they are tightened there is slippage and I can't see any obvious way to fix this.

Regards,

Tom

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1 hour ago, orley said:

Thanks Olly. I think it's that the weight is too much for the clutches. No matter how hard they are tightened there is slippage and I can't see any obvious way to fix this.

Regards,

Tom

Would it help if you took off the clutch levers and repositioned them?

Ololy

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