Structural simulation of a 16" cellular primary mirror for an astronomical instrument
16 F3.5 Supremax 33 primary
16 F3.5 Supremax 33
primaryP201407i-011shibumiProblemsBorosilicate glass
(Pyrex/Supremax) is getting expensive. The open market price of
telescope mirror blanks in the profitable size range (16 up) is
nearly USD1000.Need to reduce glass use or use something else.
Epoxy/CFRP still too bleeding edge. Conical hub-mount is good but
polishers dont like working with them. So cellular is the way to go
for now.Requirements/customer expectations changing. The demand is
for short F-ratio force-cooled precision optics for CCD
photographic use, in a transportable package. Demand for cheap
light buckets now being met from China with machine-polished BK7
and plate glass optics unprofitableNeed to focus on eliminating
forced cooling (vibration, cost and simplicity) through better
passive cooling dynamicsReliable precision optical figure
requiredControlled mirror mounting (no interference by
amateurs)Only sell blanks to most reputable polishersProfessionally
tested interferometry or (preferably) Shack-Hartmann wavefront
analysis.Mirror cell designs are crap. Very few meet the reasonable
tip/tilt requirements of short F/R optics. Almost none eliminate
all mirror movement with different instrument pointing position.
None offer electric collimation. None offer primary mirror focusing
to reduce equipment clutter around the focal
plane/focuser.Integrate the primary and the mirror cell and use RTV
bonded mirrorsProvide edge & face protection (front baffle)
which also masks turned-edgeEngineer tip/tilt/focus mount with
wireless control appSell as a premium package
2shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 4429609Structural
design
3Support surfaces for optician are in red16 F3.5 borosilicate
optic optimised for minimal print-thru and very low gravitational
shape change.Located by central pin and RTV ring bond.Designed for
fast thermal equilibration and minimum mass and cost.shibumi | www.
shibumi-consulting.net | [email protected] | ++353 (0)1 -
44296090.25Psi Polishing pressure; back supported on flat areas
only
4It appears that the thin faceplate will lead to minimal print
thru effects provided that polishing pressure is
well-controlled.shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 44296090.25 Psi
Polishing pressure: support side of optic
5shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 442960945 deg Altitude
pointing6
shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 442960945 deg Altitude
pointing (rear)
7shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 4429609Zenith Altitude
pointing
8shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 4429609Mounting surfaces
for Optic
9shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 4429609
10shibumi | www. shibumi-consulting.net |
[email protected] | ++353 (0)1 - 4429609
