Precision CNC
Clearance Specials In Stock
Skywatcher 10 Collapsible Mount.
Azimuth Bearing Laminate Rings
Dobsonian Mounts
Current lead time: 6-8 weeks.
Overview Of Mount Choices

Standard Solid Mounts.
Custom Solid Mounts
Custom Collapsible Mounts
Collapable mount videos 1 and 2
Dobsonian Mount Accessories.
Height Adjustment Stands.
Digital Setting Circles
Nexus II
Sky Commander
Amateur Telescope Making
Mirror Cells, Mirror Masks
Mirror Masks.
Aperture Masks
Sharpening Double Stars!
Altitude Bearings
Standard 12" And 18" Bearings.
Fix For 5" Small Bearings.
Altitude Bearing Guides.
Altitude Bearing Supports.
Clamshell Rings For Tubes
Upcoming Items
Contact us to inquire.
Mirror Box Integrated Cells.
Rotating Tube Rings.

Upper Tube Assembly Rings.
Anonymous Survey
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Sharpening Those Double Stars.

12" and 6" masks shown.

Aperture Masks

Custom Paired Sharpening Masks

A great aspect of double star, and lunar and planetary observing is the availability from suburban skies. Enjoy fun targets any good night without seeking darker skies.

Optimizing your Newtonian/Dobsonian's performance to produce sharp refractor-like views is completely within reach! Our custom masks achieve a clear aperture, eliminating diffraction spikes from your telescope's spider, curing for possible image softening turned down edge (TDE), and preventing distortion from intruding mirror retaining clips.

We will custom cut a mask that hides the the mirror retaining clips, and create a custom sized aperture mask, providing a clear, perfectly round uninterrupted aperture. This will give crisp clean views and fine details on the Moon and planets, and round spike free image for splitting tight double stars.

Mirror masks are laser cut 1/8" thick black acrylic, stiff, light weight with a non-reflective matte side. Long slots to the diameter of your mirror allow precise centering to the mirror edge. Attach to mirror clip tops with Velcro dots or similar using small notches for positioning.

Aperture masks are laser cut ultra-light weight sturdy 0.035" thick Formica 909-42 Crystal laminate. Dimensioned to fit to your outer tube diameter, center hole cut if you have a protruding spider stalk. Maximum mask aperture opening computed based on your secondary size and spider vanes.

Doubles Sharpening Order:

We will e-mail for necessary dimensions including: mirror size, mirror clip width, mirror intrusion, diameter of secondary mirror holder, spider stalk if applicable,three or four vane spider. Write with any question.

10" f/5.7 optimized for doubles.
Turned Down Edge

Authoritative optical tester Dick Suiter discusses masking mirrors (see #2) to improve image quality.

"Turned down edge (TDE) Outside of proper parabolization, edge problems are the most common maladies afflicting mirrors. A turned down edge, or TDE, is a narrow zone, no more than 1/8 inch [3mm], at the extreme edge that turns downward, focusing long. If the zone is wider then it is called a rolled edge. Rarely the extreme edge will turn upward, focusing short. This is called a turned up edge." - Mel Bartels