Heavy load

[neilm]

I've posted this question the in beginners help and advice, but, as I guess it's not related to a 20" dob or its got every one thinking...I though I try it here amongst my fellow bino users.

Question is, have a Manfrotto tripod body that has a max load rating of 7kg and the Manfrotto head rated at 5.5 kg. Would it be safe/okay/mad to use this set up with a pair of bins that weigh in at 5.5 k

Cheers

Neil

[BinocularSky]

No clear-cut answer; it's one of those "it depends" ones. Remember that tripod heads are usually designed for photo/video work; that does not usually include pointing at the zenith. In fact, several Manfrotto heads (I use the 501) are limited to an elevation of around 60* -- you need to reverse the head to get any higher (see my page on mounting binoculars for more info).

The next issue is that of turning moment on the pitch (elevation/depression) axis. This is not a problem when you are observing at low altitude, but it increases as altitude increases; it is at a maximum when you are pointing the binocular vertically. Given that most, if not all, manufacturers are optimistic abut the capacity of their tripods/mounts, this is likely to be where you will feel the limitations of your set-up -- the stated capacity might be OK when you are observing horizontally, but it won't be OK for astronomy. It is even worse if you are using an L-bracket (as opposed to mounting the binocular directly to the mounting plate) because this takes the binocular even further from the pitch fulcrum, thus increasing the turning moment. I find that, above about 75*, I have to have the pitch axis so tight that it makes finding and holding targets to be difficult. This is why I got a decent parallelogram mount.

I hope that helps; please do ask if you think I can be of use.

[neilm]

Steve,

Thanks very much for the advice and the link to the mounting binoculars page, all very useful information. Looks like I'll be hitting the bank account, again!

Cheers

Neil

[Nexus 6]

Excellent advice give by Steve, I took it when I asked what to use with a set of Helios 20x90's they weigh 3.6 kgs so well below your choice. I did use the 501 head and Manfrotto 475b tripod. Ultimately I did find them all just too awkward to use, perhaps it have been different with the Parallelogram.

Am now using the Celestron 15x70's and a set of 8x42's from Visionary which are superb.