15.11.2020 PA altitude adjuster continued.

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Sunday 15th and another cloudy day. Though with lots of small, blue "teasers" in between the fluffy stuff.

9.30 51F and it is sunny but windy form the east! Blowing straight into the dome if I open up now.

After yesterday's struggle to remove the turnbuckle's U-bolts I discovered my proposed changes would not help. I would have to dismantle the entire mounting to add extension plates with all that entails.

The upper horizontal arrow shows the present position of the cheap, fencing turnbuckle. As can be seen it represents a smaller radius tangent than a longer turnbuckle fitted below. With a U-bolt fixed on the RA motor plate. 

Even then, I don't think I gain much in radius and the stainless steel turnbuckle is still too long. This needs more thought. I don't have any more 20mm scrap aluminium for new [support fork] side plates. 

Though I could move the pivot southwards to improve the overall balance of the pivoted mass. Though at the expense of moving the bulk of the the entire mass even further southwards. 

That could be fixed by moving the altaz hole in the base plate southwards too. Which would shift the whole mounting mass northwards. Though that means there is no room for the RA drive motor. Not unless I cut a huge chunk out of the pier! Not possible! 

Though I could rotate the RA motor mounting plate to the top or to one side. Being low down it was out of the way when I moved around south of the pier. It didn't catch on my bulky winter clothing. Pointing the motor plate to the east would be best. This would fill the gap where the laptop sits on the desk.

It's Catch 22 whatever I change. Including separating the mounting into units. Each is so heavy that it needs paired and lashed stepladders and the chain hoist! The pulleys could never cope and they might tear down the top of the dome along with the zenith board! Not worth the risk! I should only use the pulleys for changing telescopes. Dragging a pair of builders stepladders up to the dome is very hard work. Lifting the heavy chain hoist up to the top is even worse!

This all needs very serious thought before I do anything. Rotating the RA motor plate is relatively trivial. Drilling the support fork is only possible if it is free of any load to allow dismantling. The tines need to be stacked on the drill press table to ensure coincidence of the 16mm, drilled holes. Placing 10kg of weights on the bottom of the PA is far too little to help improve the balance.

A further idea would be to tilt the fork tines backwards [to the south] some more. This would move the C of G of the entire mounting. It would still need the fork to be free so that I can drill and tap new holes in the base of the tines. This would arguably be the best option. It shifts the perpendicular of C of G. While simultaneously moving the RA motor away from the pier. The contact faces would be much longer as well. 

Some drawings, overlaid on photos of the mounting, soon showed that the entire mass would overhang the base plate if I redrilled the support fork tines for the altitude pivot. Not clever! I would have to move the tines northwards to compensate. 

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