Astroscan
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The Astroscan was a wide-field 4⅛" clear-inch (105mm) diameter
reflecting telescope A reflecting telescope (also called a reflector) is a telescope that uses a single or a combination of curved mirrors that reflect light and form an image. The reflecting telescope was invented in the 17th century by Isaac Newton as an alternati ...
, originally produced by the
Edmund Scientific Corporation Edmund Scientific Corporation, based in Barrington, New Jersey, was founded in 1942 as a retailer of surplus optical parts like lenses. It later branched out into complete systems like telescopes and microscopes, and in the 1960s, a wide variety ...
, that was for sale from 1976 to 2013.


Design

The Astroscan had a
Newtonian reflector The Newtonian telescope, also called the Newtonian reflector or just a Newtonian, is a type of reflecting telescope invented by the English scientist Sir Isaac Newton, using a concave primary mirror and a flat diagonal secondary mirror. Newton' ...
layout with a 4⅛" clear-inch (105mm) diameter f/4.2 aluminized and overcoated
borosilicate glass Borosilicate glass is a type of glass with silica and boron trioxide as the main glass-forming constituents. Borosilicate glasses are known for having very low coefficients of thermal expansion (≈3 × 10−6 K−1 at 20 °C), ma ...
parabolic
primary mirror A primary mirror (or primary) is the principal light-gathering surface (the objective) of a reflecting telescope. Description The primary mirror of a reflecting telescope is a spherical or parabolic shaped disks of polished reflective metal ...
with a
focal length The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...
of 17½ inches (445mm). The telescope's
secondary mirror A secondary mirror (or secondary) is the second deflecting or focusing mirror element in a reflecting telescope. Light gathered by the primary mirror is directed towards a focal point typically past the location of the secondary. Secondary mirr ...
was mounted on a flat optical window at the front of the tube. Edmund designer
Norman Sperling __NOTOC__ Norman Sperling (born March 19, 1947) is an author, editor, publisher, teacher, and telescope designer living in San Mateo, California. Sperling received a BA from Michigan State University after graduating from Montgomery Blair Hig ...
and optical engineer Mike Simmons came up with the basic design and Peter Bressler Design Associates did the detailed work on this simple introductory telescope. Rather than using a more traditional
equatorial Equatorial may refer to something related to: *Earth's equator **the tropics, the Earth's equatorial region **tropical climate *the Celestial equator ** equatorial orbit **equatorial coordinate system ** equatorial mount, of telescopes * equatorial ...
or
altazimuth mount An altazimuth mount or alt-azimuth mount is a simple two-axis mount for supporting and rotating an instrument about two perpendicular axes – one vertical and the other horizontal. Rotation about the vertical axis varies the azimuth (compass bea ...
the Astroscan features a spherical housing around the primary reflector which sat in a cast
aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...
cradle. The design was durable and allowed for simple operation by novice amateur astronomers; it won an Industrial Design Award in 1976. The telescope body was made from high impact acrylonitrile butadiene styrene (ABS) plastic and was equipped with a carrying strap to aid portability. Because it was targeted at the novice market the telescope had its limitations: The general design was for low power hand-held or wide-angle work, the short f/4 focal ratio did not allow for high magnification without the image degrading, and the primary mirror was factory aligned with no provisions for adjustment. The Astroscan came with 15 mm and 28 mm focal length RKE eyepieces, giving it a magnification of 30X and 16X respectively, with a 3.0 °
field of view The field of view (FoV) is the extent of the observable world that is seen at any given moment. In the case of optical instruments or sensors it is a solid angle through which a detector is sensitive to electromagnetic radiation. Humans a ...
using the 28 mm eyepiece, and a 1.6 ° with the 15 mm.


History

When Edmund Scientific introduced the telescope in 1976 they called it "The Edmund Wide-Field Telescope" with a Part Number "2001" Edmund had a public contest which ran until November 15, 1976, to come up with a name. The winning name was "''Astroscan 2001''". The "2001" part of the name was dropped over time. The Astroscan continued to be available after Edmund Scientific was acquired by Science Kit and Boreal Laboratories in 2001 with the telescope for sale on the "Edmund Scientific" website. Production and sales of the telescope ceased in 2013 when the mold for the plastic body broke. In 2016 the Edmund Scientific website, now called Scientifics Direct, began offering a more common format altitude-azimuth mounted 4.5 inch table-top Newtonian telescope labeled the "Astroscan Millennium". There are reports of a
Kickstarter Kickstarter is an American public benefit corporation based in Brooklyn, New York, that maintains a global crowdfunding platform focused on creativity. The company's stated mission is to "help bring creative projects to life". As of July 2021, ...
campaign by one of the original Astroscan creators to fund production of a new version based on the original Astroscan telescope. Scientifics Direct expected to have the Astroscan back in production in early 2017. Scientifics Direct's website stated they would reintroduce the original Astroscan design in late 2020. At this time the production of the Original Astroscan will be placed on hold until the quality and price point can be comparable to the original. See the Astroscan Millennium for a comparable price point and wide-field telescope. Scientifics Direct, Astroscan Millennium
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See also

* Infinite-axis telescope


References


External links


Cleaning the Optics of the Edmund Astro-Scan Telescope
* ttp://www.everythingintheuniverse.com/blog/astroscan-memories Astroscan Memories by Norman Sperling, January 15, 2011 {{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System Telescopes Amateur astronomy