18
point mirror cell
Dobsonian telescopes tilt in only 1 axis, so most mirror cells have
a "sling" which cradles the mirror so it won't slip. The sling
provides even support to prevent stressing the mirror out of shape.
An Equatorial telescope tilts in 2 axis, so the mirror needs to be supported
evenly on all sides of the cell. This cell has an aluminum wall 1/8"
thick that was pre-rounded before attachment to the base. The wall
radius tolerance is +/- .020". Then a piece of "cove" is placed
between the mirror and wall to allow a gap of about .010".
Note the 3 safety keepers toward the top of the wall, also a safety
bolt attaches the cell to the mirror box through the bottom.
Mirror Cell design program by David Chandler
MIRRORCELL.ZIP
The program needs to be unzipped, then run under a MS-DOS Prompt.
It will give you the radii of the points for just about any configuration.