[ATM] overshot sagitta correction stroke

["mahesh" <mahesh_p_n@hotmail.com>]

Hi, 

I am currently grinding a 10in mirror to make an f/5 telescope. 

Unfortunately, I have overshot the sagitta and landed with F=46in at the 320 grit stage. 

To correct this, I first tried around 10 wets of TOT 1/3COC stroke with 320 grit. Then another 10 wets of the same stroke with 220 grit, both without any success. 

After reading the suggestions posted in the archives, I shifted to the long W stroke. Even after 20 wets of this stroke with 220 grit there is no appreciable change!

So I request your help with the following:

1) What stoke will be efficient in reducing the sagitta?

2) Since I would like to end up with an f/5 mirror, what should the focal length be at the 220/320 grit stage?

Thanks.

 

with regards,

mahesh

 

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