Questar Corporation: Difference between revisions
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* Specially built Maksutov Cassegrains for use in test range imaging and radar calibration/[[boresight]]ing. |
* Specially built Maksutov Cassegrains for use in test range imaging and radar calibration/[[boresight]]ing. |
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==The Questar 3 |
==The Questar 3-1/2” Maksutov Cassegrain== |
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[[Image:Questar children ad.jpg|thumb|right|200px|"LET THEM GROW WITH A QUESTAR" - a typical advertising picture used by '''Questar Corporation''' to focus on the attributes of their product as an educational tool for children.]] |
[[Image:Questar children ad.jpg|thumb|right|200px|"LET THEM GROW WITH A QUESTAR" - a typical advertising picture used by '''Questar Corporation''' to focus on the attributes of their product as an educational tool for children.]] |
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In development since 1946, the '''Questar 3 |
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 "[[Catadioptric]]" Maksutov design, named after its inventor [[Dmitri Dmitrievich Maksutov|Dmitry Maksutov]], for the optical tube assembly. Braymer used a modified [[Cassegrain reflector|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. |
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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 focus 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 mount|equatorial]] by adding the collapsible legs included. |
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 focus 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 mount|equatorial]] by adding the collapsible legs included. |
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The Questar 3 |
The Questar 3-1/2 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 excellence, educational value for children, ease of use, and adaptations as a [[spotting scope]] and [[telephoto lens]]. The Questar of the 1950's and early 1960's 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 [[Eyepiece#Eyepiece properties|1.25" eyepieces]] and other accessories. |
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Since the telescope is made in a small production run by a relatively small company, the [[economies of scale]] have meant that the Questar |
Since the telescope is made in a small production run by a relatively small company, the [[economies of scale]] have meant that the Questar comes with a high price tag. Also the basic design has been remained almost static since its first production; one can argue the success of the concept is that it has changed little while being imitated by others. Some have criticized the 3-1/2 as being a "status symbol" that is too small and too expensive<ref>[http://homepage.mac.com/joebergeron/scopes.html Joe Bergeron's Astronomy Equipment Reviews - Questar 3.5"]</ref> for serious astronomical use; comments coming mostly from those who have not understood the value and purpose of the Questar. |
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By the 1990's accessories were made available to permit the use of the telescope around the world independent of external betteries or AC current. And the Questar now accepts many third party eyepieces and accessories. With its high performance, compact profile, and lack of periodic error a number of spectacular images are being produced by Questar owners who have mated astronomical CCD and digital SLR cameras to their Questar. |
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==Trivia== |
==Trivia== |
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Revision as of 20:16, 11 May 2007
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| Company type | Private |
|---|---|
| Industry | Manufacturing |
| Founded | 1950 |
| Headquarters | New Hope, Pennsylvania, USA |
Key people | Donald J. Bandurick, President and CEO |
| Products | Optical / mechanical devices |
| Website | www.questarcorporation.com |
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.[1][2]
Origins and history
Questar was founded in 1950 by Lawrence E. Braymer (born 1901, died 1965). A commercial artist by trade, Braymer set up Questar to develop and market Maksutov telescopes and other optical devices for the consumer, industrial, and government customers.
After the death of Lawrence Braymer, his widow Peggy became the sole owner of the company. In 1976 Dr. Douglas M. Knight was hired as the new President by Mrs. Braymer. In 2001 Questar Corporation was acquired by Donald J. Bandurick, President and CEO of the National Engineering and Manufacturing Company.
Products
Questar's telescopes are widely used in consumer, military, police, security, and industrial applications. Some of the products sold by Questar include:
- 3.5” and 7” Maksutov Cassegrain astronomical/terrestrial telescopes for the consumer market.
- 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/boresighting.
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 "Catadioptric" 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.
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 focus 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 3-1/2 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 excellence, educational value for children, ease of use, and adaptations as a spotting scope and telephoto lens. The Questar of the 1950's and early 1960's 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.
Since the telescope is made in a small production run by a relatively small company, the economies of scale have meant that the Questar comes with a high price tag. Also the basic design has been remained almost static since its first production; one can argue the success of the concept is that it has changed little while being imitated by others. Some have criticized the 3-1/2 as being a "status symbol" that is too small and too expensive[3] for serious astronomical use; comments coming mostly from those who have not understood the value and purpose of the Questar.
By the 1990's accessories were made available to permit the use of the telescope around the world independent of external betteries or AC current. And the Questar now accepts many third party eyepieces and accessories. With its high performance, compact profile, and lack of periodic error a number of spectacular images are being produced by Questar owners who have mated astronomical CCD and digital SLR cameras to their Questar.
Trivia
- This model was originally envisioned as a 5” 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.
- A Questar Standard 3-1/2 instrument resides in the collection of the Smithsonian Institution in Washington, D.C.; it is "cut-away" to reveal the various innovations unique to the Questar.
- 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[4].
- Questar optics are hand-aspherized to reduce higher-order abberations, in order to achieve a mininum 1/8th wavelength accuracy.
- Versions of the Questar 3.5” were used by NASA during its early years. The first telescopic images of earth taken by astronauts in space were with a Questar 3.5” from a Gemini spacecraft. The Apollo astronauts used Questars on their missions to the moon as well.
- Questars have been popular with many well-known scientists and other personalities; Wernher Von Braun purchased one in 1959[5]. 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.
- For a while Questar sold a shorter f/7.8 version of this optical tube assembly to be used as telephoto lens called the Questar 700.
- A 7-inch model was introduced in 1967 for 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. Later, Questar re-designed its original Questar 7 barrel and re-named it the Titanium Light Weight Classic Seven. The light weight aspects are incorporated in both the Classic Seven (including the control box) and in the current production Astro versions.
- While it was produced in very limited numbers, Questar offered a 12 inch aperture optical tube assembly that was typically sold for industrial applications and not optimized for astronomy. Some barrels were sold coupled with a German equatorial mount based on a Byers drive system.
- 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).
- A Questar telescope is used by the hit-man (Charles Bronson) in the 1972 film The Mechanic.
- Questars have been employed for long distance cinematography in movies including The Eiger Sanction with Clint Eastwood in 1975.
References
- ^ Astronomy - Partial Eclipse of the Setting Sun - "My other small telescope is a Questar, the classic Maksutov that for fifty years has been a kind of Rolls Royce for amateur astronomers."
- ^ Questar - birder 90mm - "Questar is truly the Rolls-Royce of spotting scopes"
- ^ Joe Bergeron's Astronomy Equipment Reviews - Questar 3.5"
- ^ J.R. Cumberland, Inc - Questar
- ^ Kennedy Space Center's Amateur Astronomers' "A TELESCOPE FROM HISTORY OWNED BY DR. WERNHER von BRAUN"