This 22" f5 binocular has a 25" diameter footprint and is 9˝ feet tall. The telescope is portable, weighs 338 pounds, and fits in the back of a minivan. At home, it sits on an isolated concrete pier and is protected by a roll-away enclosure that can be completely removed from the observing deck.
Five of these binoculars were made; three in collaboration with the Three Rivers Foundation (3RF) in Texas. The first one was completed in 2003. Since then, a number of changes have been made, primarily in the top end: from circular composite rings to steel hex rings to braced hex rings; from a fixed to an adjustable spider; and from a stepper drive system to one with servo motors used with Sidereal Technology's controller.
This is the largest binocular built for visual use. While the 8.4m Large Binocular Telescope (LBT) at Mt. Graham, Arizona, and the Meyer Binocular Telescope at Mt. Evans, Colorado (operated by the University of Denver) are both larger, neither converges images from each side for visual access. The LBT will combine light using interferometry. The Meyer telescope's dual-mounted 0.7m Ritchey-Chrétien's are used individually.
The two top ends are welded steel hex rings, with bracing to stiffen the focusers. The spider is suspended with wires. Each side is focused individually, and is joined with the other side for interpupillary adjustment. The tertiaries are attached to the bottoms of the focusers. Two light baffles are located on the sides and one in the middle.
Two-inch eyepieces are used to provide larger real fields and shorter focal lengths. This optimizes viewing at lower magnifications.
The secondaries are suspended by wires in a structure that permits precise centering of the secondary mirror in both the mechanical and optical axes of the telescope. Without these adjustments, eyepiece positions may end up being offset both horizontally and vertically. To compensate for this, the user must unnaturally tip or rotate his or her head. This sort of adjustment is unnecessary in smaller binoculars, but with a 22" f5 they are magnified noticeably.
The mount contains two C-rings that are located between the mirrors to provide a more compact footprint.
Struts are retained with machine screws and strut connectors both at the top hex ring and the mirror cell at the bottom. Strut braces at the struts' midpoint stiffen the tube.
Collimation motions are provided by adjusting nuts on three bolts on the outsides of the cells. Convergence adjustments, used to adjust the parallelism of the binoculars, are also located on the same bolts. These are separate from the collimation adjustments and do not alter collimation.
The binocular uses a drive system based on Sidereal Technology's servo motor controller. The drive motors, gearheads and clutches are mounted on a flex rocker for a direct, friction-roller drive.
The drive frame, a flex rocker, rotates on a welded aluminum azimuth ring. The inner part of the ring is a raceway for the azimuth telescope encoder.
The cell is glued to the mirror with RTV (silicone). This eliminates the need for lateral supports, which simplifies design and reduces cost. The cell is lifted up off the mount for transportation.
No observers who have used any of the eleven 22" mirrors glued with this cell have claimed to have noticed any astigmatism. JMI glues mirrors in their NGT telescopes. The Steward Observatory Mirror Laboratory at the University of Arizona fearlessly uses ordinary RTV to lift 8-meter class mirrors.
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Richard Berry described his observing experience with Lee Cain's 17˝" binocular telescope at the 1984 Texas Star Party as "...defying description: I discovered that the quality and sheer realism, for lack of a better term, of an image viewed with two eyes greatly exceeds any monocular image I've seen...on closing one eye, I still had a splendid view, but the subtle impression of the nebular glow as grainless, smooth, silky, and fluid, and the faint western extensions of the [Lagoon] nebula, were lost with one eye." (Telescope Making 23, 1984, p. 34).
When attending a Sacramento Valley Astronomical Society star party I had a chance to see the Whirlpool Galaxy through another member's Fujinon 25x150 binoculars. It was my first encounter with giant binoculars. M51's spiral structure was easily visible, but I couldn't detect it later that night using my 6" richest-field telescope, an instrument with the same aperture size and magnification.
Inspired by the Fujinon's surprising performance and encouraged by reports that binocular vision enhances nearly every aspect of visual perception for amateur astronomers, I decided to make a large binocular telescope. I first built a 12˝" binocular; it compelled me to build the 22".