Equatorial Wedge Design

by Ed Stewart <stargazera_tskymtn.com>

Photo-Wedge General View WedgeStabilizer I put my Meade 7" Maksutov on a wedge made from Baltic Birch plywood. This is a high density plywood that is a magnitude stronger than cabinet-grade plys. I have seen and used a similar product at Home Depot that is from S. America and the thickness is designated in MM, i.e., 3/4" is 19mm, at about half the price of Baltic Birch.

My wedge is just a simple, non-adjustable design with the latitude base plate at my latitude of 30 degrees. Adjustments for polar alignment good enough for visual observing are made with the tripod legs. A small 6 X 30 finder was added to one of the fork arms to make this easier. Also can put the OTA at 90 degrees and look through the Telrad finder.

Some ideas on making this an adjustable (partially, anyway), would be to:

  1. don't mount the latitude base plate in a dado joint.
  2. running along the top of the latitude base plate, mount a threaded rod running through both side boards with either nuts or threaded knobs that would tighten against the side boards after an altitude adjustment in the latitude base plate.
  3. do the same thing running along the bottom of the latitude base plate, but have slots cut into the side boards in an arc to allow the latitude base plate to be moved up or down to made the altitude change.
  4. a large threaded bolt could come up through the base board to bear the weight of the latitude base plate and to make the altitude adjustment more precise when the rods in step 2 & 3 are loose. Similar to the Meade Wedge in concept.
  5. as to azimuth adjustment, I have found that pinching (literally), the two southern tripod tips along the ground is easy and controllable in small amounts.
  6. alternate wedge designs can be found at this Mapug.com URL along with modifications to the Meade SuperWedge: <Wedge/Tripod Modifications>

 

Drawings: 

Wedge Back View

Back View

Wedge Side View

Side View

The BowTie Cross Member is shaped that way to allow sufficient access to the mounting bolts for the OTA's base when it is installed or removed.

Photo-Wedge Parts
 

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