File:Hubble mirror polishing.jpg

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DescriptionHubble mirror polishing.jpg	English: Hubble Space Telescope Primary Mirror: This photograph shows the Hubble Space Telescope's (HST's) Primary Mirror being ground at the Perkin-Elmer Corporation's large optics fabrication facility. After the 8-foot diameter mirror was ground to shape and polished, the glass surface was coated with a reflective layer of aluminum and a protective layer of magnesium fluoride, 0.1- and 0.025-micrometers thick, respectively. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST and the Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors.
Date	1 March 1979
Source	NASA Marshall Space Flight Center Collection (NIX MSFC-7995584)
Author	NASA Marshall Space Flight Center
Permission (Reusing this file)	NASA

	This file is in the public domain in the United States because it was solely created by NASA. NASA copyright policy states that "NASA material is not protected by copyright unless noted". (See Template:PD-USGov, NASA copyright policy page or JPL Image Use Policy.)
	Warnings: Use of NASA logos, insignia and emblems is restricted per U.S. law 14 CFR 1221. The NASA website hosts a large number of images from the Soviet/Russian space agency, and other non-American space agencies. These are not necessarily in the public domain. Materials based on Hubble Space Telescope data may be copyrighted if they are not explicitly produced by the STScI.[1] See also {{PD-Hubble}} and {{Cc-Hubble}}. The SOHO (ESA & NASA) joint project implies that all materials created by its probe are copyrighted and require permission for commercial non-educational use. [2] Images featured on the Astronomy Picture of the Day (APOD) web site may be copyrighted. [3] The National Space Science Data Center (NSSDC) site has been known to host copyrighted content. Its photo gallery FAQ states that all of the images in the photo gallery are in the public domain "Unless otherwise noted."

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	Date/Time	Dimensions	User	Comment
current	22:51, 6 June 2020	3,000 × 2,401 (1.29 MB)	TD-Linux	Reverted to version as of 14:44, 3 February 2011 (UTC) (previous revert seemed to be a mistake - this version matches https://www.nasa.gov/sites/default/files/thumbnails/image/1979_hst_primary_mirror.jpg)
	09:21, 20 September 2019	439 × 324 (36 KB)	Martinlisa4828	Reverted to version as of 14:45, 6 April 2007 (UTC)
	14:44, 3 February 2011	3,000 × 2,401 (1.29 MB)	AtomCrusher	Colour original res.
	08:12, 5 February 2009	256 × 194 (35 KB)	Lycaon	was upscaled
	14:45, 6 April 2007	439 × 324 (36 KB)	Levg	{{Information \|Description= Polishing of Hubble's primary mirror begins. \|Source= http://history.msfc.nasa.gov/book/chpttwelve.pdf \|Date= May 1979 \|Author= \|Permission= \|other_versions= }}