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East Heavy Improvement


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Last night, as an experiment,  I thought I'd adjust the RA balance on my mount to be slightly east heavy. 

Pleasantly surprised to get pretty consistent results beneath 0.75RMS - which for my mount is a 20% to 30% improvement . Obviously it's just one session and there are many other factors but if you haven't tried it yet it may be worth a go.

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This is why friction drive is so good. The mighty Mesu has no backlash.  :grin:

Newcomers reading this might not know that the Dec equivalent of east-heavy loading is running slightly out of polar alignment and guiding only in the direction needed to correct for this. Again, the disabled direction has to become the active one after a flip.

Olly

Edited by ollypenrice
Clarification
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13 minutes ago, Clarkey said:

I'll have two please.😄

Not sure SWMBO would approve.🙁

The trick is to be impossible to live with on account of  mount backlash problems. Done properly, this will see you given a Mesu next Christmas. It worked for me - twice.

:grin:lly

  • Haha 1
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A way round having to change the weight after the flip is to spring load the axes.  The idea is attach a brake around the shaft whose tension you can adjust.  The brake encounters a sprung obstruction as the axle rotates, compressing the spring.  The brake pressure is adjusted so the axle slips when the spring pressure reaches a certain level (before the spring bottoms out).  So the spring acts as a restoring force just like the slightly heavy weight.  And the spring pushes in the same direction whatever the flip.  

Same technique on the DEC axis removes backlash in the gears over a short range (until the spring relaxes), but is enough to give bidirectional DEC guiding over a session - but obviously you have to approach the target from the compressing direction to have the spring loaded up.

Simon

P1450706.JPG

P1450775.JPG

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