GSO Dob base - make it collapse??

[erick]

Scott's post elsewhere:-

http://www.iceinspace.com.au/forum/showthread.php?t=27687 See #21

has got me thinking. How can I modify a GSO Dob base to make it collapse flat(ish) for transport?

Here is a US supplier that has given me ideas:-

http://www.astronomy-mall.com/FirstBase/

I would say we leave the ground board and base board together, but find a way to remove the three support boards. Hinge them with two quality piano hinges so the three can fold flat, then find a way to reconnect them to the base board - fit some brackets and insert bolts and wing nuts?

I think the main issue may be the wear and tear on the particle board - perhaps remake the three support boards out of plywood?

Anyone else have a solution?

Eric :)

[PhilW]

A couple of thoughts here:
1) It is always a good idea to get rid of particle board. It is too weak, too heavy, too hygroscopic - too everything
2) The hinge idea should work, assuming removable diagonal bracing
3) In my other post I have a more radical solution: if the upper end is really light (OK, which assumes a truss), then the balance point moves down the tube & the rocker box can shrink accordingly. Then it doesn't need to fold. Bonus: it also gets much stiffer. Using oversize bearings helps the geometry too.

Phil

[Karlsson]

Eric,

Perhaps here is an idea: http://www.orionoptics.co.uk/DOBSONIAN/dobsonian300s.html
The mounts are available separately - not sure if they are collapsible, but they are compact, not so heavy (looks like 13kg for a 12" tube) and much less prone to weather-influences than anything made out of wood.

Admittedly, 300 quid looks a bit pricey, but it should be possible to DIY with some help from a workshop - or something like it...

[Tannehill]

I've seen a few Al or even stainless steel Dob mounts, going the heavy route to reduce the volume problem. All a rocker box it, really, is a way to fairly rigidly support those 4 teflon pads for the tube trunnion. Just needs a way to spin well in Az, and it's solved. (Easily said, of course) I seem to remember someone just having two Y-shaped steel pieces bolt onto a thick rockerbottom with some angle brackets to help secure it to the wood. Heavy, but when unassembled took up very little room, and nearly indestructable. Don't know costs and such....I expect a plywood collapsiing rocker base would be cheaper, but probably more vulnerable to wear and tear...

s