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Sagitta

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Posted by Steve Campbell on February 24, 2002 12:29:05 UTC

Your calculations are correct,you should have a 0.055 depth for an 8"/f9, however 1/16" is 0.0625
so FL=radius squared/4(d)....=64" divided by 8 = 8, F/8 is your focal ratio,you overshot,16/4x0.0625=64",use reflected sunlight to confirm this,wet the mirror with soapy h20,
you may be happy with f/8, if not, grind with tool on top to increase FL,check FL FREQUENTLY,but use reflected sunlight to check this, feeler gauges and drill bits are not a very accurate means of measuring FL, dont use too much "over-hang" if you must increase the FL!,the natural tendency is to do so, you'll roll down the edge if you do!
Good luck.

Follow Ups:

Sagitta....and flexing. - ldcrenshaw - February 24, 2002 - 13:13 UTC
- Sagattia - bobmay - February 24, 2002 - 22:49 UTC
  - Thanks...and one dumb question. - ldcrenshaw - February 24, 2002 - 23:32 UTC
    - ROC - bobmay - February 25, 2002 - 19:11 UTC
      - Yes I did, Bob ! - ldcrenshaw - February 26, 2002 - 21:51 UTC
        
        Yes I did Bob: was figuring sagitta - jkoptic - February 27, 2002 - 05:28 UTC

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