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After wasting a couple of hours carefully making a 1mm thick, plastic disk shim it proved not to be needed. My worm shaft measurements with a straight edge in the semidarkness were false. Today in bright daylight I used a long jawed, Vernier caliper and discovered the original worm height was fine. Trying to slew with the worm now set too high merely resulted in endless noisy stalls. Removing the shim again returned the drive to a peaceful normal.
During my levering operation to make room for fitting the split ring shim I discovered the mounting balance was poor. Loosening the wormwheel clutches was not nearly enough. There was still too much friction to judge the balance properly. I was just fooling myself. Imbalance is very obvious when you learn how to do it properly.
Slacking off the worm assembly freed the shaft completely. The OTA now proved to be too light compared with the counterweights. Adding a half kilo weight [1lb] to the outer OTA frame almost neutralized the imbalance. After that the RA drive would slew 180° using the IH2 Handset without noise or complaint. Unfortunately even Cartes Du Ciel won't connect with AWR-ASCOM now.
I have now wiped grease all around the wormwheel teeth with a rubber glove clad finger. Just adding lubricant to the worm alone hadn't made it spread visibly along the wheel rim.
It was quite breezy today and the shutters kept opening or closing by themselves. I'll have to add sliding bolts to the bottoms of the shutter ribs.
Just as a local experiment I have washed two mold-blackened plywood panels with brown soap. Then rinsed off with a sponge and clean water. Finally drying them off with paper towels. Many of dome panels are going dark but do not look as if they are sourcing rain from the outside joints. The mold often appears as patches in the middle of the panels. Perhaps the covering paint has trapped moisture from rain in the previously exposed plywood? The lightweight tarpaulins were very poor protection.
Some panels are completely untouched. As are sheets of identical but unpainted ply resting in the lower observatory building. There is certainly no shortage of ventilation in the dome. The weather is remaining damp but rather mild for this time of year at around 50F/10C. I don't feel it would be safe, nor sensible to paint directly over mold. The humidity reading is maxing out at 35% on the inside of the panels. With the remaining timber construction much lower.
Wednesday: Under a horrendously overcast sky I aimed the 7" folded refractor at some distant trees to check image quality. It was surprisingly good. I would easily have seen flies on the leaves had they been present. I used the IH2 handset to pan slowly across the tops of the woods.
It is surprising how the appearance of the dome changes constantly with the light and the weather. I must admit to a preference when it looks completely matt and smooth due to frost or heavy dew.
Just as a local experiment I have washed two mold-blackened plywood panels with brown soap. Then rinsed off with a sponge and clean water. Finally drying them off with paper towels. Many of dome panels are going dark but do not look as if they are sourcing rain from the outside joints. The mold often appears as patches in the middle of the panels. Perhaps the covering paint has trapped moisture from rain in the previously exposed plywood? The lightweight tarpaulins were very poor protection.
Some panels are completely untouched. As are sheets of identical but unpainted ply resting in the lower observatory building. There is certainly no shortage of ventilation in the dome. The weather is remaining damp but rather mild for this time of year at around 50F/10C. I don't feel it would be safe, nor sensible to paint directly over mold. The humidity reading is maxing out at 35% on the inside of the panels. With the remaining timber construction much lower.Wednesday: Under a horrendously overcast sky I aimed the 7" folded refractor at some distant trees to check image quality. It was surprisingly good. I would easily have seen flies on the leaves had they been present. I used the IH2 handset to pan slowly across the tops of the woods.
It is surprising how the appearance of the dome changes constantly with the light and the weather. I must admit to a preference when it looks completely matt and smooth due to frost or heavy dew.
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2 comments:
I would try mixing some oxalic acid crystals with some warm water and wipe the ply panels with this. If possible hasten the drying with a hot air gun. The panels should return to their original new look Rinse again with clean soapy water. Oxalic acid is not harmful to your skin unless you have a cut but is highly toxic and so wear gloves.
regards
John Saunderson
Hello John and many thanks for the interesting suggestion.
Oxalic acid is available here but the dire safety warnings have put me off even trying it. Applying such a potentially toxic material to the inside an overhanging dome is rather different to working on a piece of wood on the bench. I would need serious eye and skin protection according to the sales website description. The difficulty of reaching much of the dome only adds to my worries.
Best regards
Chris
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