NavList:

Dave,

You are correct that a reference ring change will offset the averager reading from zero. If you intend to use the averager often then the ring adjustment won't work for you. You will need to adjust the index prism screws (harder than it looks). Do small adjustments (loosen one screw 1/16 turn then tighten the other) with the top and bottom prism screws (don't mess with the smaller side error screw). The horizon can be used to get you close to the desired reading for your height of eye. The horizon prism is adjusted last with zero degrees and minutes on the octant then use small adjustments so that the two superimposed horizon images are in co-incidence.

Or just apply the current index error readings to bubble and natural horizon observations.

Greg Rudzinski

[NavList] Re: AN-5851-1 Repair
From: harwoodd---com
Date: 27 Nov 2011 00:49

Greg,

I agree, I think I'll just live with the shutter issue if I can otherwise avoid a tear down.

I found the adjustment you described. My concern is that if I make this adjustment it may result in the averaging counter reading off. My logic is that the counter currently outputs precisely what is on the micrometer drum readout after the two minute run. If I change the "reference ring" without a corresponding adjustment to the gear train my counter will no longer agree with my micrometer drum.

If my concern is unfounded, I shall make the adjustment. If it is valid, I think I'll leave well enough alone.

Is there any problem with simply applying the correction as index error? Would such a large value of -17 cause discrepancies in sight reduction?

Thank you for your time and photo's.

Dave Harwood

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