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My posts keep getting longer and longer as I think of new ideas. So I have had to split up the last post on the new pier. There's humour [pun] in there somewhere.
I am now leaning [another pun!] towards a more compact, more vertical, offset pier up to the Obs. floor level. The 55° bend will be reinforced with multiple layers of vertical 18mm plywood. Both externally and internally.
The leaning section at
55° will have a square cross section of about 40x40cm. With solid, 4x4" timbers
in the corners for stiffness. All clad in 18mm plywood. The leaning
section will be about 250cm along the top. Measured up the incline from floor
level close to the south wall. I leaned a pole against the mounting to find a suitable position for the axes crossing point. Even this simple action was balked by the presence of the original observatory walls.The new building walls are at least 30cm beyond the present north and south walls.
Ideally it should be possible to walk around, or step over, the base of the pier where is rises from the floor. This will avoid having to move about under the bulky, mounted instruments. I shall have to move the RA wormwheel to just under the Dec housing.
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I still haven't a clue where my imaging desk will go. The instruments will pass right through the area under the north pole. Which is where my desk is wrapped around the present pyramidal pier. I may end up facing the SE or SW observatory wall. This would provide better shelter from direct sunshine and wind. Though my own body heat might rise through the telescope's light path.
I hardly dare mention the need for my 27" imaging monitor. Will it need to be moved around too? Two fixed cables. The screen best facing north to avoid direct sunlight and/or a bright southern sky. It presently sits on a universal mounting plate on the north face of the pier. A definite No-Go area with the astrograph mounting.
It isn't a simple matter of fitting wheels or castors to a mobile desk. There are multiple cables to manage. Wireless control of the drives is not a feature of AWR[Tech]UK. Only my mouse and keyboard are wireless.
Still without computer control thanks to continuing problems with the ASCOM[AWR] driver. So I can't manage planetarium Gotos or even return to Park. Not that it ever went directly to anything [at all] in all the time I have been paying £50 a year for it.
The observatory will be over a meter greater in diameter than at present. Which suggests much more room is available. However, I shall be housing longer instruments. Which wouldn't swing inside the present 10' dome. So I have been concentrating on high resolution, [closeup] Solar H-alpha with the 6" f/10 refractor. Albeit with a long filter stack projecting from the focuser.
Both the 7" f/12 and 10" f/8 demand a larger turning circle. Moreover, they will swing in areas presently denied to them by the German Equatorial Mounting's severe, geometrical constraints. One can't mount large instruments on either end of the Declination axis. Not without endless collisions with the pier. If one instrument is looking east or west above the Pole. Then the other must [inevitably] be under the pole and facing exactly the same way. When they are pointing south then they will fill an area above and below the pole. Taking up much of the northern floor area and southern dome space.
A fork mounting might do it. Provided one were willing to limit pointing. To the area of the sky well away from the Pole. A fork, long enough to allow such long instrument to pass safely inside it, would be prodigious! The ridiculously long fork tines would be trying to bend in all directions.
Better to let the pier take the strain. A pier can be built as massively as desired or needed. With the Dec axis a simple bearing box. Rotating on a Polar Axis plate. Which is sitting right on top of the sturdy pier.
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