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Mon
day 28th 2/60F, overcast. Brief glimpses of the sun after lunch. A lost cause, but here I am all set up anyway. Now I just need 
the disk to show for long enough to Sync and start tracking. The gulls are circling overhead with a ploughing tractor roaring nearby.
Clouds coming from the east? Breaking up! Seeing reasonable. I was able to capture quite a number of videos in a short time. Which is all I had.
At first the seeing was steady with a fair amount of detail. Slightly softer than yesterday. Which is promising. Though it soon became thermally mobile. Then the overcast returned. I was incredibly lucky to be ready at the right time. It didn't look at all promising.
I have order a Lunt 1.25" Herschel Solar Prism for the 90mm f/11 Vixen"finder." The years-old foil filter is diluting the view with stray light. It also means I have to remember to check I have fitted the dewshield filter before every imaging session. I can safely fit the Lunt wedge and forget about it. I was using a 1.25" 90° star diagonal anyway.
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2 comments:
Hello Chris, apologies if this is not the best way to contact you but I need some help with a Fullerscopes Mk3 mount. I have a synchronous RA motor and it seems to have a clutch or maybe a gearbox, but the RA shaft seems to turn against the gear although there is sufficient friction for the drive to work after a fashion. I'd love your thoughts on how this should work. With best wishes, Guy
Hello Guy,
The MkIII uses mains, gearbox synchronous motors to drive the worms. The worms drive the small, bronze wormwheels. These have large thumbscrews or hex socket grub screws to apply pressure to the axis/shaft. At least this was the original set-up on mine.
There are also simple clutches on the motor drives to the worms. These use a grub screw in bell shaped bronze couplers to drive the worm shafts.
It is quite possible that your mounting has different arrangements fitted by owners over the years. Corrosion may have locked the thumbscrews or motor drive clutches.
All mountings need balancing to avoid the drives working "uphill." Corrosion of the original steel shafts will increase friction in the main bearings. This could cause slipping in the drives.
Note that original screws will have different threads to the modern universal Metric.
If you search for "Fullerscopes MkIII" or "MkIII drives" way back around 2010 I had various illustrated blog posts on my MkIII mounting. Also later posts when things cropped up.
If I haven't answered your specific query do get in touch again.
Regards
Chris
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