Astronomy Observing Chair
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Introduction
This project is an Alt-Az observing chair for comfortably viewing the entire sky, particularly the zenith, with somewhat heavy 20x80 binocs.
Altitude and azimuth steering is done with feet, resulting in quick, smooth motions to any part of the sky.
Azimuth movement is achieved with six roller bearings made for roller blade wheels.
The bearings are permanently attached to the lower base on the ground, and a large piece of formica on 1-inch particle board provides very smooth azimuth motion over the bearings.
Altitude movement is made with two 3/8-inch bolts placed just above the center of mass, passing through holes in the wooden armrests.
The chair section rests on the two lateral supports rising from the rotating formica base, and lifts right off for easy handling and transportation in two separate pieces.
Parallel swingarms made from upper sections of a broken Slik tripod, support the binoculars and allow locking them at various elevations for observers of different body sizes.
The binocular support beam between the swingarms slides in and out to fine-tune eye relief distance and locks for hands-free observation.
The observing chair turned out better than anticipated at a very low cost of $30 plus some spare parts already available from other projects.
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Nice features
- No-hands use after binoc elevation and eye relief adjustments are made for each observing session.
- Easy access to the whole sky from the entire horizon to the zenith is enjoyable for hours without a break.
- Lightning fast slews with massive leg power uses no batteries.
- Works wonderfully on the bed of a pickup truck using the handrails to precisely aim all over the sky with feet.
- Very sturdy construction is wind-proof and very silent, the only source of any noises are the bearings during short slews.
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Existing problems
- Requires an elevated foot support when used on flat ground in order to tilt back all the way to the zenith.
- 20X magnification results in visible shaking from heartbeats, larger powers can only be worse, not shure how to cancel out a heartbeat!
- Getting out of the chair is possible but the chair needs a locking mechanism to be left unattended with the very high CG of the binocs on it.
- Placement of altitude axis near CG results in great sensitivity to weight shifts, extra attention is necessary when lifting arms or legs.
- Opennings remain where careless hands and fingers could enter and result in injury.
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Enhancement ideas
- Add digital setting circles for altitude, azimuth, and binocular arms elevation plus a laptop to display a live map.
- Stronger swingarms for supporting larger binoculars and possibly a compact reflector telescope.
- A more unstable altitude axis closer to CG may make it possible to aim the chair with small arm/leg movements by weight shift only.
- Motorized go-to capability with sidereal tracking, built-in stereo speakers, laptop support, webcam, LED lighting, map holder, beverage holder and coffee warmer.
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More Photos
Dude-less:
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With dude:
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Close-ups:
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