ATM RE: Focal length adjustment.

[BOB PRABOWO <BOB@bahana.co.id>]

Hi Eli ,
>Will I be able to make an adjustment that large in a reasonable amount
>of
>time working TOT with #180, or should I go back to 120 and work it off
>there? 

Yes you can lengthen it by working TOT with #180, don't have to go back
to #120. Just remember to check the focal length after each wet. I
didn't do it while rough grinding my mirror and the result was I
exceeded the f.l a few times (I did 3 wets TOT, checked the f.l., oops I
excedeed the desired f.l., and then I did 2 wets MOT, again exceeded the
desired f.l). I assumed that if after 3 TOT I exceeded the f.l, than I
can fix it with 3 TOT. I was wrong!

The lesson I learnt was that I can not just assume that the focal length
reached after 3 wets MOT can be fixed with 3 wets TOT, I think the
amount of water, the pressure you apply, and the abbrasives amount  make
the difference. So, check it from time to time.

Good luck,
Bob P. Sumitro
Jakarta, Indonesia
the new land of the free

"To be able to express your opinion freely, free of fear -- ain't that
great!" 

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>Eli VV
>Coburg, OR
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