[ATM] first figuring of my first mirror, what did I do wrong?

[bobmay at nethere.com (Bob May)]

Remember that stroke and be able to accurately describe it to us all as that
is the stroke that removes TDE very nicely.  Some people can do it while
most of us do something else that either makes a bad TDE or, at best, get a
decent spherical shape.
The stroke described in Berry's book should make a surface that will tend to
go parabolic.
I had one person a long time ago in the class that was able to do that same
thing - he actually figured a mirror that looked like an excellent parabola
as we actually measured it and saw a 1/20th wave figure with it but
unfortunately, the direction of the KE was just like yours, going in rather
than out.
Problably the best first thing I can tell you is to try and not push down on
the part of the mirror that is overhanging the lap and see if that gets the
mirror going the right way.
I'll also note that I think that it is the Houghton (sp?) design that wants
a oblate spheroid if you want to make one of those.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net