Telescope Reviews: A much improved tripod for a CG5 equatorial mount

Here is a much improved tripod I built for a Celestron CG5 equatorial mount. IMO the main weakness of the CG5 tripod was mainly due to the extruded aluminum U channel legs with an open structure and that the tripod had only three members. A six member tripod is much more rigid. Many
years ago I built a tripod using six 36" long closed structure tubular rod members with tapered ends that had been gotten at an aircraft surplus. The six member tripod was vastly superior in rigidity and strangely enough didn't appear to weigh any more than the wobbly
three legged tripod. Here is a picture of the six member tripod:

At one end of each of the six rods that make up the tripod
is a spherical rod end so each of the three legs, consisting of two rods, can
articulate about the top triangular plate. Shown here is a top view of the tripod:

Notice the aluminum cylinder protruding
below the triangular top plate the purpose of which is for preloading each of
the three legs using stranded wire cables connecting each leg as shown here:

To breakdown the tripod for
transport one unhooks the wires from two of the legs and pivots the legs around
the triangular top plate so the legs fold into a nice compact package. Here is
a picture of the inverted tripod not quite totally collapsed:

and
a flattened view:

I still use the tripod for a counterbalanced parallel arm mount I
made to hold a pair of 11x80 binoculars and didn't want to modify the tripod so that it could not be used for holding binoculars. The solution was to make an
adapter plate that bolts into three tapped 1/4-20UN holes (made using a hand drill)in the tripod that
were the only modification. The adapter plate was made using a lathe and holes machined using a mill with rotary table from a scrap piece of 3/4" thick 6" diameter 6061-T6 aluminum round I had. The only modification to the equatorial head was to tap
three 10-32UN holes using the rotary table on the mill in the base as shown here:

Here are top and bottom views of the finished 6" diameter adapter plate:

Here is a picture of the adapter plate bolted to the equatorial mount head:

Shown here is a picture of the equatorial head with adapter plate on the tripod:

The beauty is that all of the functions of the equatorial head are retained such as fine polar alignment adjustments. The new mount is way more rigid than with the stock tripod. I am now more ready for the upcoming transit and hope to get a few photos and movies of Venus transiting across the sun. Here is a picture of my setup for viewing the upcoming transit that consists of a CG5 mount on new tripod, 5" F10 Max Bray Mak-Cass scope with full aperture Baader filter:

Don

Edited by don clement (06/04/12 12:34 PM)