SATLASUltraviolet · Space
GALEX
Galaxy Evolution Explorer
EndedEnded 28 June 2013, after starting 28 April 2003.
A 50 cm Ritchey–Chrétien telescope with a 1.2° field imaged simultaneously in the far-ultraviolet (135–175 nm) and near-ultraviolet (175–275 nm), with grismslitless spectroscopyPlacing a dispersing element (often a grism, a prism–grating combination) in the beam with no slit, so every source in the field gets a spectrum at once. Efficient for surveys; spectra of neighbours can overlap. spectroscopy. Its UV fluxes trace recent star formation in galaxies, hot stars and white dwarfs; the All-sky Imaging Survey reached m_AB ≈ 20.5.
- Operator
- NASA
- Orbit
- Low Earth orbit
- Aperture
- 50 cm mirror
- Passband
- 135 nm – 275 nm
- Launch
- 28 April 2003
- End
- 28 June 2013
Passband
Sky coverage
The All-sky Imaging Survey covered most of the sky away from the Galactic planeGalactic planeThe plane of the Milky Way's disc, a band around the sky at Galactic latitude b ≈ 0°. Dense in stars, gas and dust: rich for stellar work, crowded and heavily extincted for extragalactic surveys, which usually avoid it. and bright stars, which would have damaged the detectors; the Medium and Deep Imaging Surveys went deeper over smaller areas.
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Verified 15 November 2026.