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ATM what did I do wrong????
Hello to all,
I am working my first mirror, a 6" f8, sounds simple enough, got through
the 80, measured and I was right on, .0468 for a depth in the center. I did
all my grinding TOT. I then went to 120, did a focal check, used the sun,
bingo, + - 48 ". On to 220, 30 Micron, 15 micron. all with TOT.
everything looks awsome, did a sharpie on the 15 micron, and the grid came
out in 2 wets, and it came out evenly, checked under a magnifying glass,
not a pit in site that isnt of the same size as the others. that tells me
good things.
But............ I wet the mirror, put up a peice of paper, flashlight, and
took another focal reading. and SOB, it is wayyyyyy off. in the other
direction to boot!!!!!!!!!!!!!!!!!!! instead of a 48" +- focal, I have a
freeking 98" focal!!!!!!, I went from .04687 to .03125!!!!!!!! this was
done with the TOT, using a "W" stroke, 1" over hang during the stroke. Now
with all the reading I have been doing, it says that if you keep the TOT,
then you will dig a deeper hole so it is suggested to swap them. well, I
decieded to not do this, and keep the TOT to maybe bring it closer to a F/7.
can anybody tell me what I did wrong?? because at this time, it looks like
I am heading back to 120 maybe 220 to get this back to the correct focal.
but it would be nice to know what I did so I dont repeat this again.
thanks to all for helping out the newbie
Charles in wilmington ma
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