Customer comments/photos.
updated 3/26/24


6" imaging Newtonian
extended back end.
GSO - Apertura - TPO

Includes imrpoved mirror cell,
eliminates mirror clip flares

ATM Altitude and Azimuth
Bearing Parts

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

Sharpening Masks

Primary:Fix Turned Down Edge.
Aperture: Eliminate spider spikes.

Primary: Remove mirror clip flare.
Spider: Remove diffraction spikes.

Clamshell & Rotating Rings

For Dobsonian mounts
For Equatorial mounts

Altitude Bearings 

Friction control capture with Incised bearing channel.

Undersized bearings cause balance problems.

Altitude bearings on a telescope are the equivalent to a balance pole for tightrope walkers. Poles spread the walker's balance out over a greater width. Too short a width (a short or no extending pole) - there is no balancing on the "tightrope". Imagine getting pushed with your feet next to each other, you are very unstable. Larger altitude bearings spread the footing "stance" and weight, widening your telescope tube's balance. Larger altitude bearings also provide finer incremental movement, each degree being wider.


12" Big Bearings.

Under-balanced factory bearings.

Big Bearings
Upgrade from undersized to 12".

Many mass manufactured Dobsonian telescopes use 5" to 5-1/2" altitude bearings, with inherent balance problems. 12" Big Bearings improve balance, motion, and add a friction/lock mechanism.

Big Bearings are designed to attach directly onto your tube's small bearings. We customize Big Bearings bolt holes to match your existing bolt pattern. Big Bearing fit flat onto existing bearings

Small Bearing Internally Mounted

Carry handles are built in.

Small 12" Bearing

Standard 18" bearings

Standard Bearings
Small (12") and Large (18").

Standard small 12" and large 18" altitude bearings have incised channels for fine tuning guides. Bearing designs have cutouts for easy lifting and carrying of your telescope. Custom cut Inside braces precisely match your telescope tube outside diameter. Choose among these options:

  • 3/8" center bolt hole for attaching to tube.
  • Holes to mount to your existing tube ring set.
  • No mounting holes (drill your own).
  • Can attach inside mount side-walls.
  • Can attach outside mount side-walls.
  • Curved bearing braces with matching bearing holes.
  • Fine tuning friction guides and incised bearing channels.
  • Other custom sizes upon request.

What you get (depending on what item you order): all parts included. Bearings, supports, support screws, teflon, laminate strips, fine tuning assembly.

What you need: Glue for laminate (contact cement), Philips screwdrivers (#12 and #4) and longer attachment bolts if necessary.


Big Bearings upgrades - 12"
BBK Big Bearings Kit  $60
BBF Big Bearings Finished $110
Small Standard Bearings - 12"
SBK Small Bearings Kit  $58
SBSK Small Bearings with Supports Kit $87
SBF Small Bearings Finished  $87
SBSF Small Bearings with Supports Finished  $107
Large Standard Bearings - 18"
LBK Large Bearings Kit   $67
LBF Large Bearings Finished $103
LBSK Large Bearings with Supports Kit $121
LBSF Large Bearings with Supports Finished $152


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including shipping cost and estimated ship date.

Your name.
Email address.
Repeat email.
Zip/postal code.
Bearing choice.