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Wednesday 5th, A frosty start with a clear, sunny morning promised. I still don't have a useful telescope set up. I don't want to struggle with mounting the 7" just for one morning's white light. It would only have to be removed again as soon as I have the 6" completed. EDIT: Ignore the following figures: I weighed the components of each refractor. The 7" weighs 16kg plus 5kg for the objective. While the 6" weighs 12 kg plus [say] 1kg for the D-ERF and holder but including the PST stack. The image [above right] shows a full scale mock/up using their present weights and moments. 16:12. The 6" can still be moved in enough to compensate for the extra weight of the D-ERF at 16:13kg. There is no need for the C of M of either telescope to fall outside its own diameter on the crossbars.
The weights of the pair of completed OTAs, mounted on crossbars, is close enough. Only their dewshields need some space between them to achieve sufficient offset.
I was able to purchase four 1m lengths of M4 studding. So I can finish the baffle tree tomorrow.
Still waiting for confirmation of dispatch of the D-ERF and holder ring from Teleskop-Express.
It is quite amazing how new ideas crop up when you follow a link online. Not necessarily anything to do with the original subject matter. I found a new idea for hinging and spring loading the worm housings. Not with a single pivot pin but with the whole motor and worm tilting into the wheel.
If the assembly is mounted on a flat bar the rounded edge can pivot in a rounded slot. With excellent constraint against end play [or backlash.] Previously, I was seriously considering using a heavy [probably brass] door hinge. Which would have multiple resisting surfaces against end play. The hinge would need to be very stiff to avoid twisting in use.
My box section, worm supports and motor housings can be seen to flex very slightly when I move the telescopes manually. This would be unlikely to occur during normal Goto slews but might be a hidden issue in tracking. I like the idea of spring loading the worm into its wheel. It avoids potential concentricity issues.
Having had to make bushes, to reduce the supplied wormwheel bores, to match my smaller shafts, it has always stuck in my mind. Though a single pivot pin is not ideal. Longitudinal forces or resistance would tend to wind the worm out of mesh. I think this would be less likely to occur with a linearly hinged system because the pressure is spread across the entire face of the worm.
Still waiting for confirmation of dispatch of the D-ERF and holder ring from Teleskop-Express.
It is quite amazing how new ideas crop up when you follow a link online. Not necessarily anything to do with the original subject matter. I found a new idea for hinging and spring loading the worm housings. Not with a single pivot pin but with the whole motor and worm tilting into the wheel.If the assembly is mounted on a flat bar the rounded edge can pivot in a rounded slot. With excellent constraint against end play [or backlash.] Previously, I was seriously considering using a heavy [probably brass] door hinge. Which would have multiple resisting surfaces against end play. The hinge would need to be very stiff to avoid twisting in use.
My box section, worm supports and motor housings can be seen to flex very slightly when I move the telescopes manually. This would be unlikely to occur during normal Goto slews but might be a hidden issue in tracking. I like the idea of spring loading the worm into its wheel. It avoids potential concentricity issues.Having had to make bushes, to reduce the supplied wormwheel bores, to match my smaller shafts, it has always stuck in my mind. Though a single pivot pin is not ideal. Longitudinal forces or resistance would tend to wind the worm out of mesh. I think this would be less likely to occur with a linearly hinged system because the pressure is spread across the entire face of the worm.
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