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Updated 11/19/24
 

 
Dobsonian Goodies

Apertura az motion/stability fix.
EZ adjust alt/az setting circles.
Height adjustment stands.
 


Mirror Masks
Sharpen images.
 
Visual: Fix turned down edge.     
Imaging: Remove mirror clip flare.
  

Mirror Cells

6" to 13.1" mirrors.
Custom calculated design
optimizes support points.

Visual cells:
Round aperture, no mirror clips.

Imaging cells:
Mirror clip flare removal photos.
Newtonian back focus cells.
 

Clamshell & Rotating Rings

Dobsonian mounts.
Equatorial mounts.
 
 
Favorite Links

Adventures In Deep Space.
Golden State Star Party.
Equatorial Platforms.
 

Mirror Masks: Visual

12" and 6" masks shown.

Detail of flat black and gloss sides.

Correct Turned Down Edge (what is TDE?)
Imaging: removing diffraction spikes see imaging masks.

Standard sizes: for 153mm, 200mm, 250mm, 304mm, 6",8", 10", 12" and 12.5" mirrors.
.
Custom size: select custom size masks entering the outside diameter (O.D.) and inside diameter (I.D.) required (up to 12.5" diameter and 1.5" wide) in the measurements box.

TDE masks cover the mirror outer 1/8 inch, where TDE usually occurs. Construction: 1/8" thick black acrylic, stiff, light weight with a non-reflective matte side. Three 0.25" holes spaced at 120 degrees allow you to precisely center the mask at the mirror edge. Use double sided sticky tape or small Velcro adhesive dots to attach on top of mirror clips.

Shipping invoiced separately: U.S. $7. Inqiure for international cost.

Mirror options:
Primary Mirror size:
Custom size:
Enter custom size:.

Prototype masked mirror clip intrusion.

Current design example 10" mask.
More on Turned Down Edge
See #2 How to improve image quality on masking mirrors .

"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