Re: ATM: 4-Point Flotation Mirror Cell... Please explain.

[Andrew.Martyn@dao.defence.gov.au]

>In private email with Richard Schwartz, he commented that I might benefit
>from a 4-point flotation cell design.  I have a foggy (very) idea of how
>this works but...

Keith, as you would be aware, the mirror plane needs to be defined by 3
fixed points. For a four point cell imagine the normal fixed points for a
three point cell. We keep 2 of those points as locating points for the
mirror to the cell, but the third we replace with a beam. The ends of the
beam become the contact points for the mirror, while the middle of the beam
is the contact point with mirror cell. As to the actual 4 location points
on the mirror, I would guess they would be at 90 degree intervals at a 0.6
to 0.7 radius. Shouldn't be too critical with your mirror.

Andy Martyn
Canberra
Australia