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Thursday: I obtained some longer, 50mm Ø, stainless steel shafts from a local engineering company for my big mounting. I have been right on the limit of allowable OTA weights for four x 5kg counterweights. Now the Dec shaft is 8" longer so hopefully no more problems. Downside is that I have to remove the OTAs and dismantle most of the mounting to reach the Tollok, compression joints and clamping screws. Which means ladders and lifting gear to cope with the sheer weight of the separate components.
Finally, I have enough polar axis to put a clinometer on it. The magnets won't work on stainless steel. Hence the rubber bands. I have rotated the image to bring the clinometer to almost horizontal for easy reading.I need to make a smarter stop ring now that I have room. Previously, only the screw clamp would fit on the very end of the stumpy shaft. There is no serious end loading. The clamp just prevents the wormwheel from falling off the shaft.
Many of the stainless steel screws I had used on the Tollok bushes were stuck fast! Two needed a giant plumbing wrench just to break them free. So I was still at it at 7pm. I have greased all of the replacement, socket head screws just in case they need to come out again.
Now I "just" need to replace the big and heavy OTAs and balance the whole lot all over again. The extra length of the Dec shaft will probably be worth at least one 5kg weight. So I have extra reserve already as well as lots more shaft on which to bung lots more counterweights. I must have enough counterweight capacity for another OTA by now. 😉
Friday: A bright and breezy day to spur me onto new labours in resurrecting my mounting after its major shaft refit. I really should paint the counterweights with the white Hammerite I bought last year. That would seriously delay matters and time is pressing. Several days of sunshine are promised and I have nothing to look through! The paint will have to wait. Even if the rusty disks do look awful. All part of the "retro steampunk" look I suppose. Perhaps I should call it "Rat Rod Observatory?"
By 13.00 I had replaced the OTAs, balanced them and had a quick look at the sun before lunch. Nothing visible in WL. One small prom in H-a. The short T-S helical focuser seems to be beyond help. The internal pin lifts out of its lower hole and the helical focuser then literally falls apart. So It's back to push-pull with 2" sockets to obtain sharp focus. This will not do! I shall have to see what can be done with another focuser. The Borg helical gets a good press but is a bit pricey.
Mid afternoon I managed a stack of extensions to achieve H-alpha focus with the binoviewer and the 2x WO nosepiece used "straight through." To discover that I had by far the best and most even spread of fine surface detail to date! A whole disk of 'orange peel' at last! Still with some useful sky margin around the disk in the Meade 32mm 4000s Plossls. No irregularities to speak of except for a few small filaments. The few scattered proms weren't particularly noteworthy either.
I have no idea of the true magnification. It can be up to 3x amplification factor from a 2x Barlow because the distance from the Barlow to the eyepiece is extended by the binoviewer's GPL. A 32mm single eyepiece would be 37.5x3 is somewhere around 100x. The resulting sun is certainly an impressive sight through the binoviewer and still comfortably bright.
Trying to use the 1.25" TS star diagonal with the binoviewers was disappointing. Strangely dim and it shows up all the muck on the diagonal mirror.
Still nothing in WL [white light] at any power. Though I could have cut my finger of the razor sharp limb I couldn't bring out any fine detail despite attempts to defocus slightly. I discovered that I couldn't reach inward focus with the Lacerta prism and binoviewers with 2x WO Barlow.
The whole tail end has to come off the 7" once I have the new focuser's base ring to work with. So I shall shorten the OTA main tube then. To ensure focus with the binoviewers and the big Herschel prism
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