Questar Telescope
Encyclopedia
Questar Corporation is a company based in New Hope, Pennsylvania
, which manufactures precision optical devices for consumer, industrial, aerospace, and military markets. Its telescopes produced for the consumer market sold under the name brand name "Questar" have been referred to as the "Rolls Royce" of astronomical instruments.
s and other optical devices for the consumer, industrial, and government customers. The Questar Standard telescope has been in production since 1954 probably making it the longest running production consumer oriented telescope.
Questar does not produce their own optics. The earliest Questars used optics produced in part by Cave Optical, but for most of their history the optics were produced by Cumberland Optical. The optics are hand-aspherized.
Questars have been associated with many well-known scientists and other personalities; Wernher Von Braun
purchased one in 1959. Talk show host Johnny Carson
, well known as a fan of astronomy, purchased an early model. Today Show founding host Dave Garroway
and Arthur C. Clarke
are other well-known owners.
Other products included:
While it was produced in very limited numbers, Questar once offered a 12 inches (304.8 mm)-aperture optical-tube assembly. Some barrels were sold coupled with an equatorial mount based on a Byers drive system. The 12" Questar also found application by NASA
for tracking launches optically (see below).
" Maksutov design, named after its inventor Dmitry Maksutov
, for the optical tube assembly. Braymer used a modified Cassegrain
design that added an aluminized spot to the Maksutov corrector plate, creating a compact folded light path (this design is sometimes called a "Spot- Maksutov). To avoid a conflict with a design patent held by John Gregory
licensed to Perkin-Elmer, Braymer put the secondary spot on the outer (R1) surface of the corrector lens. In the mid-1960s the patent issue was settled, and Questar’s Maksutov-Cassegrains after that time use the Gregory design with the aluminized spot on the inside of the corrector (R2). The design was originally envisioned as a 5 inches (127 mm) telescope, but it was decided a telescope of that size would not fit the market they were aiming for, since it would be too heavy and expensive.
Braymer designed a built-in “Control Box” that allowed the user, looking through the main eyepiece, to switch between the main telescope and a coaxial finderscope
via moving a diagonal out of the way with a flick of a knob. This also allowed a camera or other device to access the focal plane through a hole on the back of the Control Box. A knob for focus and another to switch in and out a magnification-doubling Barlow lens
rounded out the controls. The cast-aluminum double-fork arm mount was designed with a built-in clock drive
and became equatorial
by adding the collapsible legs included.
The Questar 3.5” entered commercial production in 1954, and almost immediately this “observatory-in-a-box“ was considered the "Rolls-Royce" of telescopes. Ads for the model have run in many astronomy, science, photography, and nature related magazines such as National Geographic, Scientific American
and Sky & Telescope. They have focused on the telescope's mechanical and optical quality, educational value for children, ease of use, and adaptations as a spotting scope
and telephoto lens
. The Questar of the 1950s and early 1960s offered little capacity to employ third-party accessories, although there was a range of accessories made by Questar itself. Later models have the added advantage of accepting standard 1.25" eyepieces and other accessories.
The Questar 3.5” has been available in 5 major variants:
A 7 inches (177.8 mm) model was introduced in 1967 for hobbyist, industry and government. It appears as a scaled-up Questar 3-1/2" with the integrated Control Box. But because of its high cost compared with similar-aperture consumer telescopes, the Seven has never been a big seller among the amateur market.
Versions of the Questar 3-1/2" were used by NASA
during its early years. The first telescopic images of earth taken by astronauts in space were with a Questar 3-1/2" from a Gemini
spacecraft
. The Apollo astronauts used Questars on their missions to the moon as well. For camera tracking of launches, NASA still uses 12 inches (304.8 mm) Questar telescopes mounted on an anti-aircraft gun mount.
Since the telescope is made in a small production run by a relatively small company, the economies of scale
have meant that the Questar 3-1/2” comes with a high price tag. Also, the basic design has been remained almost static since its first production. For use in the field of amateur astronomy
where resolution and light-gathering power are the primary requirements for a telescope, the Questar 3.1/2's comparatively small aperture has led the instrument to be criticized as too small and too expensive, especially in a market where instruments more than twice its aperture are available at half its price.
New Hope, Pennsylvania
New Hope, formerly known as Coryell's Ferry, is a borough in Bucks County, Pennsylvania, USA. The population was 2,528 at the 2010 census. The borough lies on the west bank of the Delaware River at its confluence with Aquetong Creek. A two-lane bridge carries automobile and foot traffic across the...
, which manufactures precision optical devices for consumer, industrial, aerospace, and military markets. Its telescopes produced for the consumer market sold under the name brand name "Questar" have been referred to as the "Rolls Royce" of astronomical instruments.
Origins and history
Questar was founded in 1950 by Lawrence Braymer who set up Questar to develop and market Maksutov telescopeMaksutov telescope
The Maksutov is a catadioptric telescope design that combines a spherical mirror with a weakly negative meniscus lens in a design that takes advantage of all the surfaces being nearly "spherically symmetrical". The negative lens is usually full diameter and placed at the entrance pupil of the...
s and other optical devices for the consumer, industrial, and government customers. The Questar Standard telescope has been in production since 1954 probably making it the longest running production consumer oriented telescope.
Questar does not produce their own optics. The earliest Questars used optics produced in part by Cave Optical, but for most of their history the optics were produced by Cumberland Optical. The optics are hand-aspherized.
Questars have been associated with many well-known scientists and other personalities; Wernher Von Braun
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...
purchased one in 1959. Talk show host Johnny Carson
Johnny Carson
John William "Johnny" Carson was an American television host and comedian, known as host of The Tonight Show Starring Johnny Carson for 30 years . Carson received six Emmy Awards including the Governor Award and a 1985 Peabody Award; he was inducted into the Television Academy Hall of Fame in 1987...
, well known as a fan of astronomy, purchased an early model. Today Show founding host Dave Garroway
Dave Garroway
David Cunningham "Dave" Garroway was the founding host of NBC's Today from 1952 to 1961. His easygoing, relaxed, and relaxing style belied a battle with depression that may have contributed to the end of his days as a leading television personality—and, eventually, his life...
and Arthur C. Clarke
Arthur C. Clarke
Sir Arthur Charles Clarke, CBE, FRAS was a British science fiction author, inventor, and futurist, famous for his short stories and novels, among them 2001: A Space Odyssey, and as a host and commentator in the British television series Mysterious World. For many years, Robert A. Heinlein,...
are other well-known owners.
Products
Questar's telescopes are used in consumer, military, police, security, and industrial applications. Products sold by Questar include 3.5” and 7” aperture Maksutov Cassegrain astronomical/terrestrial telescopes for the consumer market.Other products included:
- Surveillance versions of their Maksutov Cassegrain models
- Long distance microscopes, an adaptation of their Maksutov Cassegrain telescopes modified to image subjects at close range, used in research and manufacturing process quality control
- Specially built Maksutov Cassegrains for use in test range imaging and radar calibration/boresightBoresightBoresight is a term used to describe crude adjustments made to an optical firearm sight, or iron sights, to align the firearm barrel and sights. This method is usually used to pre-align the sights, which makes zeroing much faster.Traditional boresighting, as the name suggests involves removing...
ing - The QMax, a portable solar spectrometerSpectrometerA spectrometer is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. The variable measured is most often the light's intensity but could also, for instance, be the polarization...
built to fit their line of Maksutov Cassegrain telescopes.
While it was produced in very limited numbers, Questar once offered a 12 inches (304.8 mm)-aperture optical-tube assembly. Some barrels were sold coupled with an equatorial mount based on a Byers drive system. The 12" Questar also found application by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
for tracking launches optically (see below).
The Questar 3-1/2” Maksutov Cassegrain
In development since 1946, the Questar 3-1/2” has been the company's most notable product. Braymer’s basic concept for the telescope was one of portability, compactness, and ease of use. He used a "CatadioptricCatadioptric
A catadioptric optical system is one where refraction and reflection are combined in an optical system, usually via lenses and curved mirrors . Catadioptric combinations are used in focusing systems such as search lights, headlamps, early lighthouse focusing systems, optical telescopes,...
" Maksutov design, named after its inventor Dmitry Maksutov
Dmitri Dmitrievich Maksutov
Dmitry Dmitrievich Maksutov was a Russian / Soviet optical engineer and amateur astronomer. He is best known as the inventor of the Maksutov telescope.-Biography:...
, for the optical tube assembly. Braymer used a modified Cassegrain
Cassegrain reflector
The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, often used in optical telescopes and radio antennas....
design that added an aluminized spot to the Maksutov corrector plate, creating a compact folded light path (this design is sometimes called a "Spot- Maksutov). To avoid a conflict with a design patent held by John Gregory
John F. Gregory
John F. Gregory was an American optical engineer and a popularizer of amateur telescope making. He is credited with the design of a version of the Maksutov telescope called the "Gregory-Maksutov telescope".-Career:...
licensed to Perkin-Elmer, Braymer put the secondary spot on the outer (R1) surface of the corrector lens. In the mid-1960s the patent issue was settled, and Questar’s Maksutov-Cassegrains after that time use the Gregory design with the aluminized spot on the inside of the corrector (R2). The design was originally envisioned as a 5 inches (127 mm) telescope, but it was decided a telescope of that size would not fit the market they were aiming for, since it would be too heavy and expensive.
Braymer designed a built-in “Control Box” that allowed the user, looking through the main eyepiece, to switch between the main telescope and a coaxial finderscope
Finderscope
A Finderscope is a small auxiliary telescope mounted atop the main astronomical telescope and pointed in the same direction. The finderscope usually has a much smaller magnification than the main telescope can provide and therefore can see more of the sky. This helps in locating the desired...
via moving a diagonal out of the way with a flick of a knob. This also allowed a camera or other device to access the focal plane through a hole on the back of the Control Box. A knob for focus and another to switch in and out a magnification-doubling Barlow lens
Barlow lens
The Barlow lens, named for its creator, the English engineer Peter Barlow, is a diverging lens which, used in series with other optics in an optical system, increases the effective focal ratio of an optical system as perceived by all components after it in the system...
rounded out the controls. The cast-aluminum double-fork arm mount was designed with a built-in clock drive
Clock drive
In astronomy a Clock drive is a regulatory mechanism used to move an equatorial mounted telescope along one axis to keep the telescope in exact sync with the apparent motion of the celestial sky...
and became equatorial
Equatorial mount
An equatorial mount is a mount for instruments that follows the rotation of the sky by having one rotational axis parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras...
by adding the collapsible legs included.
The Questar 3.5” entered commercial production in 1954, and almost immediately this “observatory-in-a-box“ was considered the "Rolls-Royce" of telescopes. Ads for the model have run in many astronomy, science, photography, and nature related magazines such as National Geographic, Scientific American
Scientific American
Scientific American is a popular science magazine. It is notable for its long history of presenting science monthly to an educated but not necessarily scientific public, through its careful attention to the clarity of its text as well as the quality of its specially commissioned color graphics...
and Sky & Telescope. They have focused on the telescope's mechanical and optical quality, educational value for children, ease of use, and adaptations as a spotting scope
Spotting scope
A spotting scope is a small portable telescope with added optics to present an erect image, optimized for the observation of terrestrial objects...
and telephoto lens
Telephoto lens
In photography and cinematography, a telephoto lens is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus...
. The Questar of the 1950s and early 1960s offered little capacity to employ third-party accessories, although there was a range of accessories made by Questar itself. Later models have the added advantage of accepting standard 1.25" eyepieces and other accessories.
The Questar 3.5” has been available in 5 major variants:
- A 3.5" integrated telescope (referred to as a Questar Standard) with a star chart engraved in white on a blue aluminum sleeve (this doubles as a dewcap), around the barrel which contains a moon map.
- A 3.5" Field Model Questar, which is just the optical tube. See duplex option below. This was first offered for sale in May 1956.
- A 3.5" 'duplex' which included a simple way of detaching the telescope from the open fork mount to allow the optical tub assembly to be used as a 1240 mm at f12 telephoto lensTelephoto lensIn photography and cinematography, a telephoto lens is a specific type of a long-focus lens in which the physical length of the lens is shorter than the focal length. This is achieved by incorporating a special lens group known as a telephoto group that extends the light path to create a long-focus...
. This variant has been in production for over 30 years. - A 3.5" distance microscope that came with two barrels: the standard one, and a separate longer barrel, which could be screwed onto the duplex fork mount in place of the standard one, and used as a distance microscope. This variant came with he standard accessories, and a separate case containing the distance microscope barrel assembly.
- A 3.5" Questar Birder. This is a modified Questar Field Model with a fixed 10x finder with a rapid-focus knob used for observing Birds and other wildlife.
A 7 inches (177.8 mm) model was introduced in 1967 for hobbyist, industry and government. It appears as a scaled-up Questar 3-1/2" with the integrated Control Box. But because of its high cost compared with similar-aperture consumer telescopes, the Seven has never been a big seller among the amateur market.
Versions of the Questar 3-1/2" were used by NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
during its early years. The first telescopic images of earth taken by astronauts in space were with a Questar 3-1/2" from a Gemini
Project Gemini
Project Gemini was the second human spaceflight program of NASA, the civilian space agency of the United States government. Project Gemini was conducted between projects Mercury and Apollo, with ten manned flights occurring in 1965 and 1966....
spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
. The Apollo astronauts used Questars on their missions to the moon as well. For camera tracking of launches, NASA still uses 12 inches (304.8 mm) Questar telescopes mounted on an anti-aircraft gun mount.
Since the telescope is made in a small production run by a relatively small company, the economies of scale
Economies of scale
Economies of scale, in microeconomics, refers to the cost advantages that an enterprise obtains due to expansion. There are factors that cause a producer’s average cost per unit to fall as the scale of output is increased. "Economies of scale" is a long run concept and refers to reductions in unit...
have meant that the Questar 3-1/2” comes with a high price tag. Also, the basic design has been remained almost static since its first production. For use in the field of amateur astronomy
Amateur astronomy
Amateur astronomy, also called backyard astronomy and stargazing, is a hobby whose participants enjoy watching the night sky , and the plethora of objects found in it, mainly with portable telescopes and binoculars...
where resolution and light-gathering power are the primary requirements for a telescope, the Questar 3.1/2's comparatively small aperture has led the instrument to be criticized as too small and too expensive, especially in a market where instruments more than twice its aperture are available at half its price.
Further reading
- Sky & Telescope Magazine - November 2002, S&T Test Report : The Questar 50th Anniversary Edition Telescope
External links
- Questar Corporation’s website
- Company Seven's Questar Library Historical reprints of advertising and brochures and patents for Questar telescopes, articles about antique Questar telescopes and accessories in their museum display.