Mounting: Moving the RA wormwheel 5.

*

Wednesday: Windy.  After the struggle to fit the PA shaft through the PA bearings I found the motor clearance and position exactly as expected. After all, I had simply inverted the previous layout.

A U-bolt fitted on the top plate of the PA housing would have helped enormously if it supported the housing at the correct angle with the block and tackle.

The remaining shaft length is just adequate to allow a collar to be clamped there with radial screws. Not ideal but manageable.

There is now plenty of room for altitude adjustments via the turnbuckle hidden inside the supporting fork.

I had feared the motor fixing screws would be inaccessible but again there was no problem reaching them with a spanner.

I have yet to try any driven slews but cannot imagine any real problems. The worm/motor housing could do with fine, screw adjustment for a more accurate depthing of the worm in its wheel. I just can't decide on the best way to do it without it looking like a pig's ear designed by a committee.

I have gained a total of [at least] 110mm movement towards the south with these simple modifications. 40mm from moving the central [azimuth]  pivot to bring the round, load spreading disk to the edge of the pier. Another 70mm was gained from bringing the fork tines to the southern edge of the rectangular base plate.

There will be a smaller contribution from lowering the RA Wheel and spacer to the bottom of the PA shaft. Probably another 25mm at a guess. Or about 5" overall from all the changes.

All of which will help to ensure the mounting's C of G [assumed to be roughly where the axes cross] is brought nearer to the center of the pier.  The mounting is twisted to the north on the pier so it is difficult to capture the center in a single photograph. I may have overdone the offset slightly.

The mounting looks taller and slimmer now despite having lost quite some width and a couple of inches in height up at the top. The southerly movement should ensure I can reach the eyepiece of the straight tubed refractor. Hopefully without my head having to displace any more wood than already exists between my ears.

It was very frustrating to have the eyepiece completely inaccessible. Particularly after all the effort that went into building the dome precisely for the [long] 7" f/12 refractor. Which was why I quickly fitted the folded refractor. Then had no chance to do any real observing.

I shall now have to turn a slim, brass, locking collar to stop the wormwheel from [slowly] slipping off the bottom of the PA shaft. Instead of which I found a stainless steel hose clamp as a temporary measure. It saved my nose dripping on the lath at 34F. The wormwheel rotates with the shaft so there is no worry about wear from mutual rotation against the clamp.

Later I dismantled the stepladders and chain hoist and took them back downstairs out of the way. I just need to fit the long tube OTA back on to check the mounting's balance. Then I can try some driven slews.

Click on any image for an enlargement.

*