APM120mm binos on iOptron AZ Pro

[A40farinagolf]

I'm thinking of chopping and changing my kit yet again so that I can purchase a set of APM 120mm binos. I'd like to mount them onto my iOptron AZ Pro to provide a simple GOTO and tracking facility. The binos weigh 9Kg and the iOpton mount capacity is stated as 15Kg which means it should be well within it's theoretical limits. ( Counterweights and shaft are not shown in the first image.)

As a mechanical engineer I have a niggling feeling that the set up won't be suitable but I'm unsure why - I would appreciate your feedback please.

 

 

 

[Peter Drew]

I can't see any reason why it shouldn't be an ideal setup being as the proposed binocular has 90 degree set eyepieces.   ?

[A40farinagolf]

35 minutes ago, Peter Drew said:

I can't see any reason why it shouldn't be an ideal setup being as the proposed binocular has 90 degree set eyepieces.   ?

Many thanks, it might be me being too conservative.

The centre of gravity of the load will be a little further away from the centre of the tripod than a single refractor so I'd have to keep it as close as possible to reduce the bending moment. 

Also I've had a thought  - I could load my 130mm frac so that it weighs more the binos and then mount it on my AZ Pro in a similar position to where the binos would be and then see what happens.

[michael.h.f.wilkinson]

Sounds like a great set-up. I have a non-goto mini-giro alt-az mount, that shows not issues when loaded more to one side than the other. I do prefer to keep it balanced, but for scopes up to about 5 kg I have had no issues whatsoever (without counterweight). If you use a counterweight on the other side, you should be fine.

[A40farinagolf]

6 hours ago, michael.h.f.wilkinson said:

Sounds like a great set-up. I have a non-goto mini-giro alt-az mount, that shows not issues when loaded more to one side than the other. I do prefer to keep it balanced, but for scopes up to about 5 kg I have had no issues whatsoever (without counterweight). If you use a counterweight on the other side, you should be fine.

My hesitations are reducing and I'm in the process of deciding what items of astro kit I need to sell. I'm lucky to have some great kit and to be honest I don't want to sell anything but needs must.

[MZack]

Hi. It should be a great set up. I’ve mine on an AYO Mount with built in encoders as a push to. I’d check that the L bracket is strong enough not to bend or risk breaking. I had one custom made as I didn’t want to risk damaging an expensive piece of kit! 

[A40farinagolf]

Looks like a great set up and thanks for sharing, don't suppose they're for sale - only joking.

You're right to question the strength of the std L bracket and I've had the same concern.

Would you be willing to share the design of your custom bracket so that I could get one made somewhere?

Thanks,

M

 

[MZack]

Hi. I don’t have the detailed spec as it was designed and made by Alan Marriot of AGM Design in Stevenage. I can share his details. Some pics attached. It’s over engineered and Alan charged me £200 for design and manufacturing. It weighs 2.25kg. It was originally for my 100mm APMs but takes the 120s easily. Although it’s more costly than commercially available ones it’s supporting well over £4K worth of kit not including eyepieces. So I think it’s worth making sure you have a good bracket. The dovetail is not shown here as it’s attached to the bottom of the bins but it slides into a channel which is secured by a moveable clamp operated by two screws on the side which move the clamp up against the dovetail. You can move the dovetail along the channel to get the balance right but I hardly need to adjust it at all. Note that he designed it specifically for the AYO Mount and it’s style of clamp to attach the l bracket. The Ioptron may need a different style.  I agree with an earlier comment that counterweights are best added to keep it smooth  

Hope that helps. 

Best. Malcolm

[Stu]

Excellent bit of kit Malcolm! Well worth over engineering the L bracket, both for safety but also to minimise vibrations which can affect them if not rigid enough.

[MZack]

9 minutes ago, Stu said:

Excellent bit of kit Malcolm! Well worth over engineering the L bracket, both for safety but also to minimise vibrations which can affect them if not rigid enough.

I agree Stu. The mount sits on a Berlebach Ash tripod which is fine and good for transporting to star parties etc. I am thinking of a pillar mount for extra stability and slightly easier to get my observing chair around in the observatory. To A40faringagolf, make sure your tripod is a sturdy one as Stu points out about minimising vibrations the bins will move the centre of gravity out further than most scopes.  I have two 5kg skywatcher/Celestron counter weights on the other side although one will do if positioned at the end of the extension bar.  

Malcolm. 

[A40farinagolf]

On 24/11/2018 at 12:12, MZack said:

Hi. I don’t have the detailed spec as it was designed and made by Alan Marriot of AGM Design in Stevenage. I can share his details. Some pics attached. It’s over engineered and Alan charged me £200 for design and manufacturing. It weighs 2.25kg. It was originally for my 100mm APMs but takes the 120s easily. Although it’s more costly than commercially available ones it’s supporting well over £4K worth of kit not including eyepieces. So I think it’s worth making sure you have a good bracket. The dovetail is not shown here as it’s attached to the bottom of the bins but it slides into a channel which is secured by a moveable clamp operated by two screws on the side which move the clamp up against the dovetail. You can move the dovetail along the channel to get the balance right but I hardly need to adjust it at all. Note that he designed it specifically for the AYO Mount and it’s style of clamp to attach the l bracket. The Ioptron may need a different style.  I agree with an earlier comment that counterweights are best added to keep it smooth  

Hope that helps. 

Best. Malcolm

Hi Malcolm, Looks like a great bit of kit and apologies for my slow response as I've been snowed under recently, will study the photos in detail to help me decide the way forward. Thanks again M