Phil Rousselle of France has rebuilt his shgraph. See
a detailed description of the SHGraph
here and the optical layout
here
The specifications are
telescope : D=90mm F=1300mm
spectro : arcetri (modified) with 2 achromats D=60mm F=900 mm
grating 1800 gr/mm
image synth. linear array sensor
Fred
Veio donated his former 90/1300mm Celestron achromat of excellent quality,
1/15 wave for spherical aber, and excellent color correction as well as two
60/900mm achromats from Apogee about 1/8 wave on the wave front at infinity
focus for spherical aberration. Color correction is good. David Grosby donated a
flat 80mm mirror, 1/10 wave.
See Phil's marvelous array of solar maps in various bandwidths
here and
here
(this is a must see!!)
