DIY Equatorial Platform

[acropolite (Phil)]

Found this page, on a DIY equatorial platform while browsing a US forum, thought it may be of interest to the dobber hoards.

[erick (Eric)]

It sure is. I'd love to have an equatorial platform, but cannot afford the commercial version.

I've had a quick scan, and, though it looks complicated, I'd love to give this a go. However, I need moral and real support - some of the DIY will be beyond me. Any other dobber in Melbourne wants to work on this together with me and we'll make one for each of us - and work it out together on the "two heads are better......" theory?

(Edit: Or now I look, maybe one of the many different DIY examples I see are on the net?)

[mill (Martin)]

Erick i could help you.
I have an self build mount here in my garage and i made it totally different.
Pm me for info.

[Escortitis]

I have built a mount very similar in design to this, a European bloke has a well read site where he uses roller blade wheels etc..(can't remember link, sorry).

A big hurdle with this style of platform is the radius of those runners. there was a link on the site to a calculation program that work out the numbers if you gave it some info, height to C of G, platform size, thickness of platform, Lat. and related figures.

I have yet been able to get figures that work. I was setting it up for a 12" truss, everything went great, even using a router to make those radius' become quite simple with practice, it ran very smoothly on the runners, it's rotation however, had very little to do with that of the earth, or where i was standing.

I still have the main components of this mount, and if someone knows a different method of getting the right figures for those radii's, i would love to hear.

George.

[DavidH]

Originally Posted by Escortitis

I have yet been able to get figures that work. I was setting it up for a 12" truss, everything went great, even using a router to make those radius' become quite simple with practice, it ran very smoothly on the runners, it's rotation however, had very little to do with that of the earth, or where i was standing.

I still have the main components of this mount, and if someone knows a different method of getting the right figures for those radii's, i would love to hear.

George.

Hi George,

Are you sure that the problem is not simply polar alignment?

Most platforms should be adjustable within say 5 degrees of their intended usage lattitude, so if the platform is rotating smoothly at the right RA rate, the rotational axis should be able to be pointed at the pole by adjusting the position of the platform base. Or, to put it another way, you should be able to correct for all but the most gross building errors by adjustments.

I found that drawing the various axes and radii on a full size piece of cardboard gave me the clearest picture of what I was doing when I built mine.

Regards,
David.

[ving (David)]

nice find!

too bad i dont need it anymore, but if i did i might have given it a go...

[mill (Martin)]

The file for making the calculations is called dimen.xls and is available from the eqplatforms group in the yahoo groups.
You can find it in Files>sacred files>Warren Peter

[Escortitis]

Thanks for that info Mill, I'll compare the results of both using the same inputs and see where i went wrong.

Polar alignment was on the top of the list when i went through what could be wrong David. I had another mount that i knew was very close to correct alignment set up next to the platform, so it wouldn't have been far off. The issue was tracking along a arc that was too 'flat'.

Anyhow, will give this other program Mill pointed to and see what numbers it gives me, and I'll be sure to make a cardboard mock up of these figures first!!

Thanks guy's

Geo