New decade. New plans. Dismantling the mounting.

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Jan 1st 2020, 41F,  mostly overcast. I started by removing the three telescopes from the saddle of the big mounting. Not an easy task due to their sheer size and weight and height off the floor. Not to mention the unloaded counterweights wanting to head north in a hurry! The 7" nearly batted me out of the observation slit on one such occasion! I ought to tie off the counterweights to the dome but usually forget.

Having unloaded the Dec. shaft I then had to remove it and the saddle, to reduce the weight of the mounting. The sheer weight of nearly 4' of 50mm diameter, stainless steel shafting has to be felt to be believed! I used my 4x4 pulley system slung from heavily reinforced brackets mounted on the slit, top cross board at the top of the dome.

When I first set up the observatory I found I could not reach the eyepieces of the binoviewer on the 7" refractor. There was no room for my head between the eyepieces and the dome base ring.  So I had moved the mounting several inches to the south on the 14' tall pier.

Since then I have obtained a better focuser and star and solar diagonals with decent clamping systems. I have also shortened the 7" main tube which helped obtain more clearance. Moving the 7" up through the tube rings helped. This was possible thanks to the weight of the new 3.5" FT focuser.

Now I want to centre the mounting on the pier to minimize any bias from the considerable mass being badly off-centred. Everything added to the mounting affects the mass of the whole. Telescopes, finders, additional counterweights etc, all add to the load on the pier.

If that load is off centre on the pier it will tend to push it over in the direction of the offset. With the pier being incredibly tall, by most standards, the risk of tilt increases. This is not remotely a tree falling risk but would tend to spoil the tracking through slow, mounting, misalignment creep.

I noticed the deliberate isolation gaps closing on the south side shortly after the pier's construction. So I adjusted the screw jacks on the concrete, foundation blocks to tilt the pier. This gave a positive 1° slope to the north which hasn't really changed. I bought an inexpensive, digital clinometer to monitor such things. It is handy for checking the PA altitude angle to a claimed 1/10° at a glance. 

With the arrival of lunch I am about to loosen the central 16mm clamping bolt to free the mounting base plate. I have to be in two different places at the same time. Inside the pier to loosen the fixing bolt. And, simultaneously upstairs, taking the weight of the mounting on the pulley system to avoid a major topple. I have left the RA shaft in place, for the moment, but removed the 11" RA, drive wormwheel to avoid possible damage.

More later. If I survive to tell the tale!

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