The observing chair presented here is a very sturdy, simple and basic accessory for use at the eyepiece of the telescope. The chair can be positioned very close to the telescope with minimal interference with tripod or pier legs. The seat is adjustable over a wide range of heights and can be used from three sides. Oak was used throughout. This choice of wood was made for appearance, durability and strength. A load of 200lbs is no problem. I do not know the maximum load capacity. The lower notches are intended for a [future] footrest, the upper notches will accommodate a tall person or a high eyepiece position.
The chair is very durable and easy to use. However,
if the seat is not properly engaged in the notches, it can slip
down the rail. When you change the seat height, simply check that
the rear dowel is properly seated in the notch and the seat will
not move until you move it. It will actually get tighter with
increased weight but will always release easily.
I recommend the brass feet on the legs and rail
bottoms to protect the wood from abrasion and water penetration.
Also a hunter's "hot seat" is a must for cold nights
and a gardener's foam kneeling pad is a plus for all other nights.
The tools I used to build the chair :
10" table saw
Drill press
1-1/4" Forstner bit for the notches
Palm sander
Miscellaneous C-clamps
'Gorilla Glue'
The notched sides were made by marking the centerline of a 1"x4" Oak plank, measuring the centers of each notch and drilling the holes with the Forstner bit. Then the plank was cut down the centerline resulting in two sides with identical notches in each. This is the most complicated part of the whole project.
The whole chair can be built with hand tools. The
power tools just make the job go faster.
Bill of materials:
all of the wood is Red
Oak from Home Depot. Most, if not all, of the hardware can be purchased at Home Depot.
A. Chair rail
(2) 1" x 4"x 48" planks
B. Seat
(1) 1" x 8"x 12" plank
(1) 1-1/4" diameter Oak dowel, 36" long
(1) 15/16" x 3" x 36"
C. Legs and braces
(2) 1" x 2" x 48" planks
(2) 1" diameter x 36" long Oak dowels
D. Hardware: all bolts are 1/4 x 20 brass
(5) 3" L
(1) 2" L
(5) 1/4 x 20 friction nuts
(1) 1/4 x 20 brass wing nut
(1) 1/4 x 20 brass nut
(10) 1/4" brass washers
(2) 1/4" steel washers
(2) brass trunk corners
(2) brass corner angles
E. Wedges: made from scrap Oak.
Tips:
Drill the bolt
holes one drill-bit-size larger than 1/4" and the bolts will
be easier to install.
Tighten the leg bolts until you feel some resistance
to moving the legs.
Very little 'Gorilla Glue" is needed. The stuff
is fantastic and expensive. Buy the smallest sized bottle.