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Aperture
: Refactor sharp Newts.
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  with rotating rings.
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CNC Laser Precision Aperture Masks
Sharpen image 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 


Reflective outside, flat black inside.
100% opening is sized to fit from secondary holder outer edge to the primary mirror edge.


Custom Sized Three Aperture Masks

"Testing this new aperture mask on my 10" f/5.7 Dobsonian, I was literally stunned at the clean crisp star images. Having observed (several hundred) double stars over the past two years (2019-2021) at full aperture, dealing with a secondary spider creating spikes and other abbreviations, I can see why observers love refractors and their unobstructed views. Using the mask was a revelation. Alberio showed small circular stars with clean airy disks, and pure colors. I found stopping down to the 50% mask was best, and it was so easy to change mask sizes. Epsilon Lyrae (Double Double) revealed its magnitude differences clearly with clean separations and perfect individual airy disks." - Mark W.

When observing detailed objects such as double stars, the secondary spider of your Newtonian will create spikes in the image that can hide detail. An aperture mask will "remove" those spike distortions. And, having varying size openings will afford you more choices in brightness for achieving separation of otherwise impossible double star splits. This is really a function of increasing the focal ratio: A 10" f/6 masking to a 3" opening becomes an f/20 telescope - increasing contrast in an "unobstructed system; wonderful for brighter detail targets such as Jupiter, its moons, Saturn, our Moon, and of course bright tight double stars or tight pairs of widely divergent magnitudes.


1/8 " thick flat black acrylic; rigid, lightweight and durable.
Aperture masks have three openings: 100%, 67%, 50%.
100% is largest possible opening based on primary and secondary size.
See this sample detailed Aperture Mask Diagram.pdf.

Adheres securely to tube using Velcro dots.
Separate acrylic covers for two openings are included.
Photo is an original single opening aperture mask.
Shipping cost quoted upon request.

Price calculated by square area, $0.1465 per square inch
rounded to nearest whole dollar. Pricing examples:

Tube Outside Diameter
Sq. "
x
Price
8"
64
$0.1465
$9.00
10"
100
$15.00
12"
144
$21.00
14"
196
$29.00
16"
256
$38.00

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Primary mirror size: 
Secondary mirror holder diameter: 
Protruding secondary bolt? Diameter: 
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