Ordering Paused
Resuming January 2, 2024

Customer comments and photos.


GSO / Apertura / TPO
6" f/4 imaging Newtonian mirror cell upgrade with focal length back end extender.

 Dobsonian Mounts

Read: About Our Mounts

Standard solid
Custom solid.
Custom collapsible.

Manual setting circles: Az and Dec.
Digital setting circle installation.
Mounts for two telescopes.
Height adjustment stands

ATM Altitude and Azimuth
Bearing Parts

The Bearing Works: get everything.
Or buy individual items:
Laminate rings and strips
Teflon pads
Azimuth bolt assembly kits


Image Sharpening

Primary:Fix Turned Down Edge. 
Imaging: Remove mirror clip flare.
Aperture: Eliminate spider spikes.

Clamshell & Rotating Rings

For Dobsonian mounts
For Equatorial mounts

AstroGoods Mirror Cells

For 6 " to 13.1" primary mirrors.
Designed dimensionally to your mirror specifications for optimal performance.

6", 8" and 10" mirror cells with calaculated optimal support points. No clip intrusion in light path.

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 the optimal support points for top performance.

Our new retaining system eliminates intrusive mirror clips, or stressful gluing. We place a 1/8" thick black acrylic ring 1/8" over the mirror front, so the mirror can't tip out. The ring is supported on black 1/4" nylon posts abutting the mirror edges at 120 degree spacing, preventing unwanted/unnecessary lateral movement in the cell. Eliminating intrusive mirror clips provides a perfectly clear circular aperture for sharper images by (reducing star flaring). The tiny magnitude loss is imperceptible to the naked eye, and can also cure any turned down "image softening" edge. And our upcoming spider masks take aim at elimination of diffraction spikes in your star images for glare free views!

Type Description
SMC6K Standard Mirror Cell 6" Kit: (7.6" ID min tube).
SMC6F Standard Mirror Cell 6" Finished (7.6" ID min tube).
PMCK Premium Mirror Cell Kit (8" to 13.1")
PMCF Premium Mirror Cell Finished
PMCKF Premium Mirror Cell Kit with fan inset
PMCFF Premium Mirror Cell Finished with fan inset

The Premium Mirror Cell shown at left is our first article (prior to new acrylic ring), assembled to "dry fit" before sanding. Kits arrive assembled, just disassemble, fine sand and paint or finish.


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including shipping cost and estimated ship date.
Your name.
Phone number (for ship documents).
Email address.
Repeat email.
Zip/postal code.
Cell choice.
Mirror Dimensions
Mirror diameter.
Mirror thickness.
Focal length or ratio.
Secondary mirror diameter.
Tube inside diameter.

  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.