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Following Alex's request, I have reduced the
line-breaks in my messages to occur at 50
characters, to see if that makes things better.
Comments will be appreciated. Please note that it
seems to have made some of the symbols that
indicate quoted lines go a bit funny.

The original problem was commented on by Paul
Hirose. Indeed, I did receive that message, but
overlooked his comment at the bottom, sad to say.
Thanks to both for helping me to keep my postings
orderly.

Now back to the sextant mirror question-

After commenting on the available adjustment for
his index mirror, I had written-

| > Other adjustments, for side error and
| > index error, will be made to the horizon
mirror.

and Alex replies-
| I thought this is a standard arrangement, have
you seen sextants
| where the side error is adjusted on the index
glass??

No; you couldn't do that. But I have seen
arrangements where the index error could be
adjusted out by tweaking the index glass.

To my suggestion-

| > The mirror should be held at an
| > angle in the view of the telescope, close in
front of the objective,
| > with some arrangement of cardboard and
sticky-tape.
|
Alex responded

| Of course, I can experiment with my spare mirror
this way.
| But if the mirror is bent as a result of the way
it is attached
| to the sextant, the only way to find this out is
to fix the
| whole sextant, without detaching the mirror.

True. If you are prepared to remove the index
mirror, that would allow you to see stars
reflected in the horizon mirror only, to locate
where the problem of poor star images lies. Or
perhaps you could find some way of cobbling the
telescope to the frame at an odd angle, so you can
reflect stars into the telescope from the horizon
mirror, without the index mirror being involved.|

Alex added-

| I am not a handy man to make ingenious
experiments,
| so I thought it is better to choose math.

That's a skill that I envy.

George.

================

contact George Huxtable at
george@huxtable.u-net.com
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13
5HX, UK.

   

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