View source for Submillimetre Common-User Bolometer Array

Two instruments known as the '''Submillimetre Common-User Bolometer Array''', or '''SCUBA''', have been used for detecting [[submillimetre radiation]] on the [[James Clerk Maxwell Telescope]] in [[Hawaii]].<ref name="SCUBA2Holland" />

== SCUBA-1 ==
The older continuum single pixel UKT14 [[bolometer]] receiver was replaced in the 1990s by the Submillimeter Common-User Bolometer Array (SCUBA). The SCUBA project was green-lighted in 1987 by the JCMT board and was in development for nearly a decade before it saw first light on the telescope. While it was not the first [[focal-plane array (radio astronomy)|bolometer array]] it was "unique in combining an unparallel sensitivity with an extensive wavelength range and field-of-view".<ref>{{cite journal|arxiv=astro-ph/9809122|doi=10.1046/j.1365-8711.1999.02111.x|title=SCUBA: A common-user submillimetre camera operating on the James Clerk Maxwell Telescope|journal=Monthly Notices of the Royal Astronomical Society|volume=303|issue=4|pages=659–672|year=1999|last1=Holland|first1=W. S.|last2=Robson|first2=E. I.|last3=Gear|first3=W. K.|last4=Cunningham|first4=C. R.|last5=Lightfoot|first5=J. F.|last6=Jenness|first6=T.|last7=Ivison|first7=R. J.|last8=Stevens|first8=J. A.|last9=Ade|first9=P. A. R.|last10=Griffin|first10=M. J.|last11=Duncan|first11=W. D.|last12=Murphy|first12=J. A.|last13=Naylor|first13=D. A.|doi-access=free |bibcode=1999MNRAS.303..659H}}</ref>

[[File:Submillimetre Common-User Bolometer Array 2013.JPG|thumb|right|The Submillimetre Common-User Bolometer Array]]
SCUBA operated simultaneously at wavelengths of 450 and 850 micron (with 91 and 37 pixels, respectively), and was sensitive to the [[Thermal radiation|thermal emission]] from [[Cosmic dust|interstellar dust]]. SCUBA is ranked second only to the [[Hubble Space Telescope]] in terms of publication of high-impact astronomical research. SCUBA was retired from service in 2005, and it is now in the [[National Museum of Scotland]] in [[Edinburgh]].

==SCUBA-2==
SCUBA-2, another continuum instrument, was commissioned in 2011. This ground-breaking camera consists of large arrays of [[transition edge sensor|superconducting transition edge sensors]] with a mapping speed hundreds of times larger than SCUBA. It has 5120 array elements at both 450 and 850 micron wavelength (10,240 total pixels). It has been conducting the JCMT legacy surveys since November, 2011, including the [[SCUBA-2 All Sky Survey]], and was made available for general astronomical observations in February, 2012.<ref>{{cite web|url=https://scuba2.wordpress.com/|title=SCUBA-2 News Blog|website=SCUBA-2 News Blog}}</ref> Two ancillary instruments, FTS-2 and POL-2, add spectroscopic and polarimetric capabilities to SCUBA-2.

=== SCUBA-2 All Sky Survey ===
The SCUBA-2 All-Sky Survey (SASSy), is an [[astronomy|astronomical]] survey using the SCUBA-2 camera to map the sky at submillimeter wavelengths (850&nbsp;μm).  It is most sensitive to very cold gas and dust.  The survey started in 2011.<ref>{{cite news
 | url=http://blogs.vancouversun.com/2011/12/06/core-of-new-deep-space-camera-is-the-coldest-place-in-the-universe/
 | title=Core of new deep space camera is the coldest cubic metre in the universe
 | work=Vancouver Sun
 | date=2011-12-06
 | accessdate=2011-12-08 }}
</ref> A team of around 50 astronomers from the [[United Kingdom]], [[Canada]], the [[United States]], [[Netherlands]], and [[Japan]] aim to map a huge swathe of the sky to find rare [[galaxy|galaxies]] and [[star]]s being formed.<ref>{{cite news
 | url=https://www.dailycamera.com/boulder-county-news/ci_19492854?IADID=Search-www.dailycamera.com-www.dailycamera.com
 | title=Boulder's NIST helps astronomers view invisible space dust
 | work=[[Boulder Daily Camera]]
 | date=2011-12-08
 | accessdate=2011-12-08 }}
</ref>

The survey will achieve an angular resolution of 14 [[arcseconds]], 1800 times more detailed than the best previous full-sky map in the sub-mm from [[Cosmic Background Explorer|COBE]], which had only 7° angular resolution (25200 arcseconds).

Despite its name, the project will not be able to map the southernmost areas of the sky that are not visible from the James Clerk Maxwell Telescope in Hawaii.

SASSy is one of the major "legacy surveys" on the James Clerk Maxwell Telescope.<ref>{{cite web|url=http://www.jach.hawaii.edu/JCMT/surveys/|title=Home Page for the JCMT Legacy Survey<!-- Bot generated title -->|publisher=}}</ref>  It is the second-largest such legacy survey in terms of time on this telescope, and in terms of notional facility time is "worth" over £1 million.

The project seeks to answer the following questions:
* Is there an undiscovered population of extreme luminosity galaxies? 
* What are the number counts of bright sub-mm galaxies?
* What is the fraction of lens sub-mm sources? 
* Is there an undiscovered population of cold local galaxies? 
* How many infrared dark clouds are there in our Galaxy and how are they distributed? 
* What is the relation of infrared dark clouds to star formation and Galactic structure?
* Is there an underlying unknown population of star formation? 
* What is the fraction of clustered vs. isolated star formation? 
* What is the answer to the distributed T-Tauri problem? 
This project will also assist in the foreground subtraction and calibration of the Planck [[microwave background]] satellite.<ref>{{cite web|url=https://sci.esa.int/planck/|title=Planck|website=sci.esa.int}}</ref>

The project was led initially by Dr. Mark Thompson and Dr. [[Stephen Serjeant]] ([[University of Hertfordshire]] and [[Open University]] respectively), now expanded to a four-person co-ordinating team with the addition of Dr. [[Tim Jenness]] and Prof. [[Douglas Scott (astronomer)|Douglas Scott]] ([[Joint Astronomy Centre]], Hawaii, and [[University of British Columbia]] respectively). The collaboration includes [[Cardiff University]], UK; [[European Space Agency]]; [[Herzberg Institute of Astrophysics]] / NRC, Canada; [[Imperial College London]], UK; [[Japan Aerospace Exploration Agency]], Japan; [[Joint Astronomy Centre]], Hawaii, USA; [[Kapteyn Astronomical Institute]], The Netherlands; [[Keele University]], UK; [[Liverpool John Moores University]], UK; [[Open University]], UK; [[Rutherford Appleton Laboratory]], UK; [[SRON]], The Netherlands; [[UK Astronomy Technology Centre]], UK; [[Université Laval]], Canada; [[University College London]], UK; [[University of British Columbia]], Canada; [[University of Cambridge]], UK; [[University of Edinburgh]], UK; [[University of Exeter]], UK; [[University of Hertfordshire]], UK; [[University of Kent]], UK; [[University of St Andrews]],  UK; [[University of Waterloo]], Canada

==See also==
{{commons category|Submillimetre Common-User Bolometer Array}}
* [[Infrared astronomy]]
* [[Submillimetre astronomy|Submillimeter astronomy]]
* [[Far infrared astronomy]]
* [[Radio astronomy]]

== References ==

{{Reflist|refs=
<ref name="SCUBA2Holland">{{cite journal | last=Holland |first=W.S. |date=2013 |title=SCUBA-2: the 10 000 pixel bolometer camera on the James Clerk Maxwell Telescope |url=https://adsabs.harvard.edu/cgi-bin/bib_query?arXiv:1301.3650 |journal=[[MNRAS]] |publisher=[[Oxford University Press]] |volume=430 |issue=4 |pages=2513–2533 |doi=10.1093/mnras/sts612 |doi-access=free |accessdate=21 December 2013 | arxiv=1301.3650|bibcode = 2013MNRAS.430.2513H }}</ref>
}}

==External links==
* [http://www.jach.hawaii.edu/JCMT/surveys/sassy/ The SCUBA-2 "All-Sky" Survey: SASSy] Main web site
* [http://www.roe.ac.uk/ukatc/projects/scubatwo/ SCUBA 2] Main web site
* [http://scuba2.wordpress.com/ SCUBA-2 News Blog]

{{Astronomical Surveys}}
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[[Category:Astronomical observatories in Hawaii]]
[[Category:Submillimetre telescopes]]
[[Category:Astronomical surveys]]