Bob
):-{])) <---- madden@netcom.com madden@svpal.org Remember amateur astronomers: "keep looking for the next Universe"
On Wed, 5 Jul 1995, Tony Cecce, Corning, NY wrote:
> Bob Madden writes:
> >Now my friend is suggesting that I put a little figure in to it, but I
> >have a sense to be heavy handed and will probably over do it again. This
> >project started out to be a solar telescope - f/10 (it is actually
> >9.795). My question is why do I have to do any more figuring on it? How
> >much more do I gain? Contrast probably isn't important as planetary work.
> >I'm tired of working on it and want to built the rest. I guess if I
> >unhappy with it's performance I can always go back and finish the figuring.
>
> Pep talk time! (I'm going to type what I've told myself so many times in
> the last three months since above sounds like the other side of the
> conversation I've had with myself at those times)
>
> Bob, don't give up yet! I've just managed to get my 5.5" f5.6 to better
> than 1/10 wave. Even though this is my first mirror, I've put enough time
> into figuring that I feel like I'm an expert. The biggest lesson I have
> learned is to go slow. Try a session or two with only 5-10 minutes of
> figuring strokes with only the weight of the mirror on top. Keep your
> fingers on the sides, no pushing on top. I am still amazed at how fast
> this changes the figure. Only plan on one session a night, take your
> time and I'm sure you can get there.
>
> You really want some correction in there to be able to see fine details
> for planetary work. And be honest with yourself, do you really think
> you will ever go back and work on this mirror if you stop now? After all,
> it won't be any easier later than it will be now. It sounds like you have
> a well working lap right now. If need be take a little break and work on
> the rest of the scope and throw a figuring session in every now and then.
> But just go slow and sneak up on the perfect figure. Don't let your past
> overshooting worry you. You are much more experienced and talented now
> then you were way back then. You're almost there, I know you can do it.
>
> Tony the Energizer
>