OTA lift, load and locking system?

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It has just occurred to me that a solar H-a telescope, with an internal D-ERF, can't be simply swapped over to white light for lunar imaging. The sky is still clear, this evening and the half moon rising high. Grr? If I had a full aperture D-ERF I could loosen the thumbscrews and lift off the filter. The H-alpha stack is a simple loosen and remove too. The 6" F/10 could become a white light [H-a monochromatic] lunar imaging telescope in only a couple of minutes.  

Though I had better get busy rebuilding the folded 7". Hopefully it won't be such a burden on the mounting as the long, straight tube. What I really need is several, easily fitted OTAs. Which can be simply hooked onto the saddle when it is aligned on the Pole.

None of your silly dovetails. Which require the heavy OTA be manually supported and placed precisely in all eighteen dimensions. Then held perfectly still under one arm while the fiddly thumbscrews are tightened to hold it all in place. Which means letting go of several kilos and thousands of pounds worth of kit to deal with one hand! Eek!!

I tried a hooked bar system with slotted battens on the folded 7" framework before changing to the straight tube. Though that was still a very heavy manual lift well above my head! The image [right] shows an early view of the folded 7" on the big GEM on a low, test stand. I soon moved the RA drive wormwheel to the bottom of the PA. There is a full length dewshield which slides easily over the stumpy, permanent version.

The large. 16" Ø, galvanised ducts on the ground in the background were meant to become the moulds of a tapered concrete pier but it never happened. I built a huge, timber, pyramidal pier instead.

Aluminium slats and locating grooves would be much better for tactile feedback, stiffness and precision. Not to mention security as the OTA is lowered at 55° using the pulley system. A sort of French Cleat but square rather than wedge shaped locking surfaces.

By arranging the lift point precisely on each OTA they will hang naturally at the polar angle. I can discard the present, fiddly cords and knots. Then have a simple hook and ring system, identical for each OTA. Each OTA would be arranged to be pre-balanced. Without the need for further fiddling or adjustment once loaded securely onto the mounting.

This would even allow me to have the 10" f/8 Newtonian fitted onto the big mounting in the dome. Though only when required for occasional planetary or lunar imaging in good seeing at high object altitudes. Without having the 10" filling the entire dome and loading down the mounting with gargantuan moment arms when not in use. Which would normally be the case if I was solar imaging and the 10" became temporarily redundant.

The OTAs can all sit upright in racks as appropriate. Arranged neatly in the corners of the octagon. With security straps against toppling.

I really like this idea! It solves numerous problems and removes several hurdles to swapping OTAs at a whim. I can have my several cakes and eat them [all] too. Without having to lift anything big and heavy myself. Which was always the problem when working out of doors. Even the hefty Jumbo steps didn't help when I was tottering under the load of a big and heavy OTA! Which usually had to be lifted nearly eight feet off the ground at the saddle!

I haven't forgotten the need for appropriate counterweights for each OTA. The trick is to have a broad batten to support the Dec shaft. While the weights are fitted or removed on the east side of the mounting. The Dec shaft being arranged horizontally for safety against slippage. The weights would be stored on the base ring, nearby, ready for use.

Once the weights are safely clamped to the Dec. shaft the batten can be safely removed and the weights allowed to descend gently to the north. This automatically places the empty saddle upwards on the south side of the mounting. Where it just needs to be rotated to the vertical ready for loading the next OTA[s.]    

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