Equatorial Wedge Design
by Ed Stewart <stargazer skymtn.com> |
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:
- don't mount the latitude base plate in a dado joint.
- 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.
- 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.
- 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.
- 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.
- alternate wedge designs can be found at this Mapug.com URL
along with modifications to the Meade SuperWedge: <Wedge/Tripod
Modifications>
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Drawings:

Back
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.

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