OSIRIS (OH-Suppressing Infrared Integral Field Spectrograph) is an

integral field spectrograph Integral field spectrographs (IFS) combine spectrographic and imaging capabilities in the optical or infrared wavelength domains (0.32 μm – 24 μm) to get from a single exposure spatially resolved Spectrum, spectra in a bi-dimensional region. T ...

for the Keck I telescope in

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

. As an integral field spectrograph, it can obtain many spectra simultaneously covering a small region of the sky. As such, it combines the capabilities of a traditional

spectrograph An optical spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify mate ...

and a regular imaging

camera A camera is an instrument used to capture and store images and videos, either digitally via an electronic image sensor, or chemically via a light-sensitive material such as photographic film. As a pivotal technology in the fields of photograp ...

. The 'OH suppressing' portion of the name refers to the fact that OSIRIS has sufficient

spectral resolution The spectral resolution of a spectrograph, or, more generally, of a frequency spectrum, is a measure of its ability to resolve features in the electromagnetic spectrum. It is usually denoted by \Delta\lambda, and is closely related to the resolvi ...

that sky glow from OH molecules can be separated and removed from the spectra of the science targets. OSIRIS covers an

infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...

bandpass from 1 to 2.5 micrometers with a spectral resolution of about 3800. Combined with the Keck

laser guide star A laser guide star is an artificial star image created for use in astronomical adaptive optics systems, which are employed in large telescopes in order to correct atmospheric distortion of light (called '' astronomical seeing''). Adaptive optics ...

adaptive optics Adaptive optics (AO) is a technique of precisely deforming a mirror in order to compensate for light distortion. It is used in Astronomy, astronomical telescopes and laser communication systems to remove the effects of Astronomical seeing, atmo ...

system, it can obtain

diffraction-limited In optics, any optical instrument or systema microscope, telescope, or camerahas a principal limit to its resolution due to the physics of diffraction. An optical instrument is said to be diffraction-limited if it has reached this limit of res ...

observations on extremely faint targets. OSIRIS was developed by the

UCLA The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California, United States. Its academic roots were established in 1881 as a normal school then known as the southern branch of the C ...

Infrared Laboratory under professor

James Larkin James Larkin (28 January 1874 – 30 January 1947), sometimes known as Jim Larkin or Big Jim, was an Irish republicanism, Irish republican, socialist and trade union leader. He was one of the founders of the Irish Labour Party (Ireland), Labou ...

. OSIRIS achieved first light on February 22, 2005, on the Keck II telescope. On April 29, 2005, OSIRIS was used to observe an infrared flare associated with

Sgr A* Sagittarius A*, abbreviated as Sgr A* ( ), is the supermassive black hole at the Galactic Center of the Milky Way. Viewed from Earth, it is located near the border of the constellations Sagittarius and Scorpius, about 5.6° south of ...

. This was its first observation results. OSIRIS was moved to Keck I in January, 2012. While the instrument proved scientifically useful, it was limited by a subpar

grating A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements, but can consist of two sets, in which case the second set is usually perpendicu ...

. A new grating was installed in 2013, which improved sensitivity by a factor of 1.83.

References

{{reflist, refs= {{citation , postscript=. , display-authors=1 , title=OSIRIS: infrared integral field spectrograph for the Keck adaptive optics system , last1=Larkin , first1=James E. , last2=Quirrenbach , first2=Andreas , last3=Krabbe , first3=Alfred , last4=Aliado , first4=Ted , last5=Barczys , first5=Matthew , last6=Brims , first6=George , last7=Canfield , first7=John , last8=Gasaway , first8=Thomas M. , last9=LaFreniere , first9=David , last10=Magnone , first10=Nick , last11=Skulason , first11=Gunnar , last12=Spencer , first12=Michael , last13=Sprayberry , first13=David , last14=Weiss , first14=Jason , work=Instrument Design and Performance for Optical/Infrared Ground-based Telescopes , series=Proceedings of the SPIE , editor1-last=Iye , editor1-first=Masanori , editor2-last=Moorwood , editor2-first=Alan F. M. , volume=4841 , pages=1600–1610 , date=March 2003 , doi=10.1117/12.461775 , bibcode=2003SPIE.4841.1600L {{citation , postscript=. , title=Diffraction-limited Imaging Spectroscopy of the Sagittarius A* Region Using OSIRIS, a New Keck Instrument , last1=Krabbe , first1=A. , last2=Iserlohe , first2=C. , last3=Larkin , first3=J. E. , last4=Barczys , first4=M. , last5=McElwain , first5=M. , last6=Weiss , first6=J. , last7=Wright , first7=S. A. , last8=Quirrenbach , first8=A. , display-authors=1 , journal=The Astrophysical Journal , volume=642 , issue=2 , pages=L145–L148 , date=May 2006 , doi=10.1086/504587 , arxiv=astro-ph/0605253 , bibcode=2006ApJ...642L.145K {{citation , postscript=. , title=Efficiency Measurements and Installation of a New Grating for the OSIRIS Spectrograph at Keck Observatory , last1=Mieda , first1=Etsuko , last2=Wright , first2=Shelley A. , last3=Larkin , first3=James E. , last4=Graham , first4=James R , last5=Adkins , first5=Sean M. , last6=Lyke , first6=James E. , last7=Campbell , first7=Randy D. , last8=Maire , first8=Jérôme , last9=Do , first9=Tuan , last10=Gordon , first10=Jacob , journal=Publications of the Astronomical Society of the Pacific , volume=126 , issue=937 , date=March 2014 , doi=10.1086/675784 , arxiv=1401.4456 , bibcode=2014PASP..126..250M , display-authors=1

External links

Keck OSIRIS page
Telescope instruments