ATM Astigmatic Starlap.

["James W. Burrows" <burrjaw@halcyon.com>]

In an earlier post, I said that Texereau's mirror on p. 102 was slightly 
astigmatic:  5.4 nm RMS w/astigmatism vs. 4.0 ignoring astigmatism.  I've 
been fiddling with starlaps whose shapes are related to mirror surface 
deviations, so the late-night thought was to go through it twice and 
generate a starlap half of whose leaves would be related to the D1 
deviations, the other half to the D2 deviations from a common 
parabola.  Take a peek:

         http://www.halcyon.com/burrjaw/atm/D12.jpg

Of course, this is just an example to provoke thought - I wouldn't TOUCH a 
mirror with 5.4 nm RMS, astigmatism or not, (.985 Strehl) except to wrap it 
up and send it to the coater <g>.

These starlaps are designed for a 2/5 CoC stroke and I suppose for this 
astigmatic thought experiment, the stroke direction would be random +- 45 
deg from the measurement diameters.

         -- Jim Burrows  phone 206.244.2933, fax .0294
         --              mailto:burrjaw@halcyon.com
         --              http://www.halcyon.com/burrjaw
         -- Seattle      N47.47233, W122.36620 (WGS84)