[ATM] RE: difference 1/8 1/16 1/20 wave?

["Jerry" <wa4guu@verizon.net>]

Since the question among ATMs of "can you see the difference?" seems to me
mostly to do with how good is good enough for the mirror maker to settle for
when making a mirror, it naturally follows that the answer is not the same
for everyone. 

Let me take a different tack here.

Since frequently the reason one asks the question is to determine whether to
consider a mirror being made to be finished or not, there may be factors to
take into account that I have been missed by the purist.

Lets play a little imagination game. We will imagine a few thing and think
how life would be different if.....

Imagine if everything that you did in life had to be perfect.

Imagine that it had to be perfect the first time.

Imagine anything short of that is total failure.


Now answer this. Would you be a success or a failure? Would life be better
or worse? Would there be anything (or nothing) useful about your life?


Now back to the imagination.....

Imagine that in spite of optical theory concerning what precision one must
reach to be unable to tell the difference with further improvement,
precision of 1 wave was the limit of precision that was possible to actually
achieve on any optical element. In other words we are imagining that a
practical definition of perfection is by a fair margin not attainable.

Now answer this. Would it be worthwhile to bother to make such a flawed
instrument? Should anyone bother to make a telescope?

If you were making your first telescope mirror and you were trying for 1/20
wave but found you couldn't get better than 1 wave what would be the best
course? The effort already being expended, wouldn't it be more reasonable to
accept less than desired rather than declare failure and discard the mirror?
Would find your work to have been more worthwhile by discarding the mirror
or by using it as is?

And then the last question. Would it be worth starting the work even knowing
that you would have less than perfect?

Simple isn't it.

Jerry

  


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