Test stand/pier:

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Having only four 2m lengths of slotted angle I had to be careful how I dimensioned the test stand. It ended up 1m high with a base of 60x70cm and a top of 30x40cm. This was the largest truncated pyramid I could make out of my smartest stock. A minimum, of 3/4" [18mm] plywood will stiffen up the top end and will probably be doubled to clamp the angle iron frame firmly.

The mounting's base plate and fork with PA bearing housing were manageable without the help of the hoist. I was even able to "walk" the whole thing across the soggy, permafrost damaged grass in the rain for a picture. Though the G-cramps were essential to avoid the mounting sliding off. The overall "whiteness" is just a trick of the flat light of a heavy overcast.

The pier dimensions are just right to be able to use the eyepiece in a 2" star diagonal while seated on a normal chair. This would be with the 7" folded refractor pointing at the zenith. Anything lower would require grovelling on the [usually] wet ground. Anything taller would require a half crouched stance at the eyepiece at the zenith. Though I do have an adjustable chair and plan to image with the refractor.  Imaging would require much less grovelling and/or crouching.

The stand will give me a chance to experiment with OTA clearance and best choice of pier height in practice. When my observing platform is finally built the pier could be bolted down to the floor for total stability. Or, the base frame could be clad to provide a resting place for paving slabs  A much lower pier height would suit my 10" f/8 Newtonian. The sloping sides of  both piers could be clad in plywood for extra stiffness. A shelf or two would further stiffen the structure and provide storage for drive electronics and accessories. Though an under platform storage arrangement would be easier to protect from the weather.

I decided to go ahead and rebuild the mounting outside. To have room to test properly with an OTA on board. Two builder's folding stepladders were straightened out and tied together at one end. Then they were erected over the pier like a very tall stepladder. I clambered up the ladder and fixed a lifting strop over the apex so I could hook on the chain hoist. By moving the bases of the ladders around I could arrange the lift directly over the mounting. Soon the mounting was complete and I could throw a garden waste collection bag over it to keep the continuous light rain off.

Click on any image for an enlargement.

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