CASTOR (spacecraft)
proposed UV/blue-optical space observatory
The Cosmological Advanced Survey Telescope for Optical and UV Research (CASTOR) is a proposed space telescope mission led by the Canadian Space Agency. With its 1-meter diameter primary mirror, CASTOR would provide imaging capabilities in the ultraviolet (UV) and blue-optical regions at a spatial resolution similar to that of the Hubble Space Telescope (FWHM of 0.15 arcseconds), but over an instantaneous field of view about 100 times larger. CASTOR was selected as Canada's highest priority for space astronomy in the 2020s in the 2020 Long Range Plan for Canadian Astronomy.
Description
CASTOR will complement the upcoming Nancy Grace Roman Space Telescope, Euclid space telescope, and Vera C. Rubin Observatory. These three major wide-field imaging facilities will not have access to the UV portion of the electromagnetic spectrum. CASTOR has been specifically designed to provide this missing capability, with high sensitivity and observing efficiency at UV and blue-optical wavelengths.
Using dichroics, CASTOR would enable simultaneous imaging of three bandpasses (UV from 150 to 300 nm, u from 300 to 400 nm, and g from 400 to 550 nm) over an instantaneous field of view of 0.25 square degrees. In addition to its imaging capabilities, CASTOR will also be equipped with additional instruments enabling high-precision photometry for the monitoring of bright targets, as well as two spectroscopic modes: low-spectral-resolution slitless spectroscopy over the entire imaging field and configurable DMD spectroscopy to provide intermediate resolution spectra in the UV in a parallel field.
The public source identifies “CASTOR (spacecraft)” as proposed UV/blue-optical space observatory. This brief keeps that definition visible, then builds a research path around CASTOR, spacecraft and proposed.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Apr 18, 2026. The linked authority identifier is Q60853745. None of the 0 selected statements returned an explicit reference. The first chronological checks are 2020.
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This entry incorporates text from “CASTOR (spacecraft)” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.