Customer comments and photos

 Dobsonian Mounts

Read: About Our Mounts
Standard solid
Custom solid.
Custom collapsible.

Manual setting circles.
Digital setting circle installation.
Mounts for two telescopes.
Height adjustment stands

Setting Circles

Custom manual setting circles.

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

CNC Laser Precision Aperture Masks
Sharpen views for lunar, planetary and double star observing.
Remove diffraction spikes caused by spider vanes.

Example aperture mask on 10" telescope.
Openings: 100% 3.7", 75% 2.77", 50% 1.85"
Two 4.33" interchangeable covers.

Sample Aperture Mask Diagram.pdf 

Custom Sized Three Aperture Masks

When observing close objects such as tight double stars with a Newtonian telescope, the secondary mirror holder's "spider vanes" can distort the image. Aperture masks eliminate spider distortions. Varying size openings provide brightness choices for cleaning up and toning down the image. Aperture masks increase the effective focal ratio yielding higher contrast views: a masked 10" f/6 becomes an unobstructed 3" f/20 telescope; wonderful for brighter detail targets such as Jupiter and its moons, Saturn, Mars, our Moon, and of course tight double stars or pairs with wide magnitude deltas.

"My first views of clean crisp star images were outstanding. Using my 10" Newtonian on double stars, the secondary spider created distortions. Using the mask, I can see why refractor's unobstructed views are so desirable. Alberio showed small perfectly circular clean airy disks with pure colors. Swapping the aperture cover, I found stopping down to 50% was best. Epsilon Lyrae's individual magnitude differences became obvious showing exquisitely clean separations with perfect individual airy disks." - Jerome G.

1/8 " thick flat black acrylic; rigid, lightweight and durable.
Aperture masks have three openings: 100%, 75%, 50%.
100% mask size calculated: edge of primary to edge of secondary.
See a sample mask diagram at left.

Adheres securely to tube using Velcro dots.
Two opening covers are included.

Shipping up to 19.5" diameter: US/Canada $15/$20.
Shipping up to 23.5" diameter: US/Canada $18/$25.
Larger sizes or shipping to other destinations quoted upon request.

Order Mask:
For tube outside diameter up to:

We will send you an e-mail with a link to a dimension form. It will ask for tube ID and OD, primary and secondary mirror sizes, spider vane type (straight or curved) and number, and if the secondary holder stalk protrudes beyond the tube.