AstroGoods: Steady State Premium Primary Mirror Cells

Front: adjustable flat black acrylic retaining ring.

Rear: collimation knobs and lock screws.

Fan insert cutouts also available.

Cells are manufactured individually, designed to mirror diameter, thickness, focal length, and secondary size dimensions. This allows calculating precise support points for optimal performance.

This cell design requires a tube inside diameter at minimum 1" larger than the primary mirror.

Retaining ring eliminates intrusive mirror clips without gluing which can stress the mirror. A 1/8" thick black acrylic ring extends 1/8" over the mirror front, retaining the mirror. The ring is supported by three bolts with inner side 1/16th inch from the mirror edges 120 degree apart. Add a layer of adhesive cause around the bolt to softly prevent lateral movement. Result is a perfect circular aperture for sharper imaging by (reducing star flaring) and/or curing turned down edge that results in image softness. The tiny magnitude loss at the mirror's edge is imperceptible.

We are also now asking for testers of our new spider masks for eliminating bright star diffraction spikes to get glare free star images.

Type	Description	Price
6" Cells
SMC6K	Standard Mirror Cell Kit.	$87
SMC6F	Standard Mirror Cell Finished	$105
8" to 13.1" Cells
PMCK	Premium Mirror Cell Kit	$155
PMCKF	Premium Mirror Cell Kit with fan inset	$155
PMCF	Premium Mirror Cell Finished	$188
PMCFF	Premium Mirror Cell Finished with fan inset	$188

Kits arrive assembled. Simple disassembly for fine sand and paint or finish, then reassemble. The mirror cell at left is shown assembled for fit, prior to sanding.

Request A Quote/Order Form by e-mail.

Click for cell specifications.

Materials and manufacture:

CNC design and cutting assures precision results.
Constructed of rigid, thermally stable light weight 3/4" birch plywood.
New front ring (described below) replaces wood ring shown in image.
Cell design allows maximum openness for quick cool down.
Six-point support positions calculated for optimal performance.

Dimensions and weight:

Fully compressed front plate face to tube mounting holes: 1.25".
Fully compressed between front and back plate: 0.125".
Fully compressed collimation bolts extend 1" from rear of cell.
Back plate O.D. Designed 0.125" (0.25" total) less than tube I.D.
13.1" cell shown weighs approximately 3.6 lbs.

Retaining ring NEW!:

Now made from laser cut 1/8" black acrylic. (Replaces wood ring shown).
Eliminates mirror clips for a perfectly round mirror face, no intrusions.
Overhangs mirror edge by 0.125". Magnitude reduction is trivial.
Mirror cannot fall out through opening.
3 black 1/4-20 nylon post pass though acrylic seated into cell.
Nylon screws are safe, designed to touch outside edge of primary.
Mirror prevented from lateral movement during vertical to horizontal.
Eliminates any visible mirror clip flare.

Front plate:

Completely open design. No obstructions behind mirror (8"-13.1").
Support arms hold mirror 0.125" above front plate.

Rear plate:

Collimating knobs backed with metal washers; smooth easy turning.
Cell position can be locked with three nylon screws (8"-13.1").
Options: unobstructed or with drilled inset/screw holes for fan (8"-13.1").

What you receive and need:

Kits arrive assembled, unpainted, sanded with 80 grit.
All parts included except 0.25" tube mounting bolts and nuts.
Requires: finishing or painting and reassembly for kits.