In astronomy

Astronomy

Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

, a Photometric system is a set of well-defined passbands

Passband

A passband is the range of frequencies or wavelengths that can pass through a filter without being attenuated.A bandpass filtered signal , is known as a bandpass signal, as opposed to a baseband signal....

 (or filters), with a known sensitivity to incident radiation. The sensitivity usually depends on the optical system, detectors and filters used. For each photometric system a set of primary standard stars

Photometric standard stars

Photometric-standard stars are a series of stars that have had their light output in various passbands of photometric system, measured very carefully...

 is provided.

The first known standardized photometric system is the Johnson-Morgan or UBV photometric system

UBV photometric system

UBV photometric system, also called the Johnson system , is a wide band photometric system for classifying stars according to their colors. It is the first known standardized photoelectric photometric system. The letters U, B, and V stand for ultraviolet, blue, and visual magnitudes, which are...

 (1953). At present, there are more than 200 photometric systems.

Photometric systems are usually characterized according to the widths of their passbands:

• broadband (passbands wider than 30 nm, the most widely used is Johnson-Morgan UBV system)
• intermediate band (passbands between 10 and 30 nm wide)
• narrow band (passbands less than 10 nm wide)

Photometric Letters

The letters designate a region of a wavelength of light. Majority of the letters span from near-ultraviolet

Ultraviolet

Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

 (NUV) to visible

Visible spectrum

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...

 and majority of the near-infrared

Infrared

Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...

 (NIR).

Note, indigo

Indigo

Indigo is a color named after the purple dye derived from the plant Indigofera tinctoria and related species. The color is placed on the electromagnetic spectrum between about 420 and 450 nm in wavelength, placing it between blue and violet...

 and cyan

Cyan

Cyan from , transliterated: kýanos, meaning "dark blue substance") may be used as the name of any of a number of colors in the blue/green range of the spectrum. In reference to the visible spectrum cyan is used to refer to the color obtained by mixing equal amounts of green and blue light or the...

 are not standard colors. Orange, yellow, and green fall under visual bands, while violet and purple are under the blue bands.
Note, the letters are not standards, they are just recognized by Astrophysicists.

Filter Letter	Effective Wavelength Midpoint λeff For Standard Filter	Full Width Half Maximum	Variant(s)	Description
Ultraviolet
U	365nm	66nm	u, u', u*	"U" stands for ultraviolet.
Visible
B	445nm	94nm	b	"B" stands for blue.
V	551nm	88nm	v, v'	"V" stands for visual.
G			g, g'	"G" stands for green (visual).
R	658nm	138nm	r, r', R', Rc, Re, Rj	"R" stands for red.
Near-Infrared
I	806nm	149nm	i, i', Ic, Ie, Ij	"I" stands for infrared.
Z	900nm		z, z'
Y	1020nm	120 nm	y
J	1220nm	213nm	J', Js
H	1630nm	307nm
K	2190nm	390nm	K Continuum, K', Ks, Klong, K8, nbK
L	3450nm	472nm	L', nbL'
Mid-Infrared
M	4750nm	460nm	M', nbM
N			N1, N2, N3
Q			Q'

Filters Used

The filters currently being used by other telescopes or organizations.

Units of measurements:

• Å = Ångström
  Ångström
  The angstrom or ångström, is a unit of length equal to 1/10,000,000,000 of a meter . Its symbol is the Swedish letter Å....
  
  
• nm = nanometer
• μm = micron
  Micrometre
  A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...
  
  

Name	Filters									Link
2.2m telescope at La Silla, ESO	J = 1.24μm	H = 1.63μm	K = 2.19μm	L' = 3.78μm	M = 4.66μm	N1 = 8.36μm	N2 = 9.67μm	N3 = 12.89μm		2.2m telescope at La Silla La Silla Observatory La Silla Observatory is an astronomical observatory in Chile with three telescopes built and operated by the European Southern Observatory organisation, and several others are partly maintained by ESO... , ESO European Southern Observatory The European Southern Observatory is an intergovernmental research organisation for astronomy, supported by fifteen countries...
2MASS/PAIRITEL	J = 1.25μm	H = 1.65μm	Ks = 2.15μm							Two Micron All-Sky Survey 2MASS Observations for the Two Micron All-Sky Survey began in 1997 and were completed in 2001 at two telescopes located one each in the northern and southern hemispheres to ensure coverage of the entire sky... , Peters Automated InfraRed Imaging TELescope
CFHTLS (Megacam)	u* = 374nm	g' = 487nm	r' = 625nm	i' = 770nm	z' = 890nm					Canada-France-Hawaii Telescope Canada-France-Hawaii Telescope The Canada–France–Hawaii Telescope is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters , and is one of the observatories that comprise the Mauna Kea Observatory...
Chandra X-ray Observatory	LETG = 0.08-0.2keV	HETG = 0.4-10keV								Chandra X-ray Observatory Chandra X-ray Observatory The Chandra X-ray Observatory is a satellite launched on STS-93 by NASA on July 23, 1999. It was named in honor of Indian-American physicist Subrahmanyan Chandrasekhar who is known for determining the maximum mass for white dwarfs. "Chandra" also means "moon" or "luminous" in Sanskrit.Chandra...
CTIO	J = 1.20μm	H = 1.60μm	K = 2.20μm	L = 3.50μm						Cerro Tololo Inter-American Observatory Cerro Tololo Inter-American Observatory The Cerro Tololo Inter-American Observatory is a complex of astronomical telescopes and instruments located at 30.169 S, 70.804 W, approximately 80 km to the East of La Serena, Chile at an altitude of 2200 metres. The complex is part of the National Optical Astronomy Observatory along with Kitt... , a division of NOAO
Cousins RI photometry	Rc = 647nm	Ic = 786.5nm								Cousins RI photometry, 1976
DENIS	I = 0.79μm	J = 1.24μm	K = 2.16μm							Deep Near Infrared Survey
Eggen RI photometry	Re = 635nm	Ie = 790nm								Eggen RI photometry, 1965
FIS	N60 = 65.00μm	WIDES-S = 75.00μm	WIDE-L = 145.00μm	N160 = 160.00μm						Far-Infrared Surveyor on board, AKARI Akari Akari is a Japanese surname and given name and term meaning "light" or "glimmer". It is also associated with:* AKARI, in astronomy, is an infrared astronomy satellite developed by JAXA, in cooperation with institutes of Europe and Korea...  space telescope
GALEX	NUV = 1800-2750Å	FUV = 1400-1700Å								GALaxy Evolution Explorer GALEX The Galaxy Evolution Explorer is an orbiting ultraviolet space telescope launched on April 28, 2003. A Pegasus rocket placed the craft into a nearly circular orbit at an altitude of and an inclination to the Earth's equator of 29 degrees....
GOODS Great Observatories Origins Deep Survey The Great Observatories Origins Deep Survey or GOODS is an astronomical survey combining deep observations from three of NASAs Great Observatories: the Hubble Space Telescope, the Spitzer Space Telescope and the Chandra X-ray Observatory along with data from other space-based telescopes, such as...  (Hubble ACS)	B = 435nm	V = 606nm	i = 775nm	z = 850nm						Advanced Camera for Surveys Advanced Camera for Surveys The Advanced Camera for Surveys is a third generation axial instrument aboard the Hubble Space Telescope . The initial design and scientific capabilities of ACS were defined by a team based at Johns Hopkins University. ACS was assembled and tested extensively at Ball Aerospace & Technologies Corp...  on the Hubble Space Telescope
HAWC	Band 1 = 53µm	Band 2 = 88µm	Band 3 = 155µm	Band 4 = 215µm						High-resolution Airborne Wideband Camera for SOFIA Stratospheric Observatory for Infrared Astronomy The Stratospheric Observatory for Infrared Astronomy is a joint project of NASA and the German Aerospace Center to construct and maintain an airborne observatory. NASA awarded the contract for the development of the aircraft, operation of the observatory and management of the American part of the...
HDF	450nm	606nm	814nm							Hubble Deep Field Hubble Deep Field The Hubble Deep Field is an image of a small region in the constellation Ursa Major, constructed from a series of observations by the Hubble Space Telescope. It covers an area 2.5 arcminutes across, two parts in a million of the whole sky, which is equivalent in angular size to a 65 mm tennis...  from the Hubble Space Telescope Hubble Space Telescope The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
IRTF NSFCAM	J = 1.26µm	H = 1.62µm	K' = 2.12µm	Ks = 2.15µm	K = 2.21µm	L = 3.50µm	L' = 3.78µm	M' = 4.78µm	M = 4.85µm	NASA Infrared Telescope Facility NSFCAM
ISAAC UTI/VLT	Js = 1.2µm	H = 1.6µm	Ks = 2.2µm	L = 3.78µm	Brα = 4.07µm					Infrared Spectrometer And Array Camera at Very Large Telescope
Johnson system (UBV)	U = 364 nm	B = 442 nm	V = 540 nm							UBV photometric system UBV photometric system UBV photometric system, also called the Johnson system , is a wide band photometric system for classifying stars according to their colors. It is the first known standardized photoelectric photometric system. The letters U, B, and V stand for ultraviolet, blue, and visual magnitudes, which are...
OMC	Johnson V-filter = 500-580nm									Optical Monitor Camera on INTEGRAL INTEGRAL The European Space Agency's INTErnational Gamma-Ray Astrophysics Laboratory is an operational Earth satellite, launched in 2002 for detecting some of the most energetic radiation that comes from space. It is the most sensitive gamma ray observatory ever launched.INTEGRAL is an ESA mission in...
Pan-STARRS	uses the Sloan's g,r,i,z filters plus y = 1005nm									Panoramic Survey Telescope And Rapid Response System Pan-STARRS The Panoramic Survey Telescope and Rapid Response System is a planned array of astronomical cameras and telescopes and computing facility that will survey the sky on a continual basis, including accurate astrometry and photometry of detected objects...
ProNaOS/SPM	Band 1 = 180-240µm	Band 2 = 240-340µm	Band 3 = 340-540µm	Band 4 = 540-1200µm						PROgramme NAtional d'Observations Submillerètrique/Systéme Photométrique Multibande, balloon-borne experiment
Sloan	u' = 354nm	g' = 475nm	r' = 622nm	i' = 763nm	z' = 905nm					Sloan Digital Sky Survey Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-filter imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project was named after the Alfred P...
SPIRIT III	Band B1 = 4.29μm	Band B2 = 4.35μm	Band A = 8.28μm	Band C = 12.13μm	Band D = 14.65μm	Band E = 21.34μm				Infrared camera on Midcourse Space Experiment Midcourse Space Experiment The Midcourse Space Experiment is a Ballistic Missile Defense Organization satellite experiment to map bright infrared sources in space...
Spitzer IRAC	3.6μm	4.5μm	5.8μm	8.0μm						Infrared Array Camera on Spitzer Space Telescope Spitzer Space Telescope The Spitzer Space Telescope , formerly the Space Infrared Telescope Facility is an infrared space observatory launched in 2003...
Spitzer MIPS	24μm	70μm	160μm							Multiband Imaging Photometer for Spitzer on Spitzer
Stromvil filters	U = 345nm	P = 374nm	S = 405nm	Y = 466nm	Z = 516nm	V = 544nm	S = 656nm			Stromvil photometry
Strömgren filters	u = 350nm	v = 411nm	b = 467nm	y = 547nm	ß narrow = 485.8nm	ß wide = 485nm				Strömgren photometric system Strömgren photometric system Strömgren photometric system is four-colour medium-band photometric system for stellar classification. It was pioneered by the Danish astronomer Bengt Strömgren in 1956 and extended by his colleague the American astronomer David L...
UKIDSS (WFCAM)	Z = 882nm	Y = 1031nm	J = 1248nm	H = 1631nm	K = 2201nm					UKIRT Infrared Deep Sky Survey UKIRT Infrared Deep Sky Survey The UKIRT Infrared Deep Sky Survey or UKIDSS is an astronomical survey conducted using the WFCAM wide field camera on the United Kingdom Infrared Telescope on Mauna Kea in Hawaii...
Vilnius photometric system	U = 345nm	P = 374nm	X = 405nm	Y = 466nm	Z = 516nm	V = 544nm	S = 656nm			Vilnius photometric system Vilnius photometric system The Vilnius photometric system is a medium-band seven-colour photometric system , created in 1963 by Vytautas Straižys and his coworkers. This system was highly optimized for classification of stars from ground based observations...
VISTA IRC	Z = 0.88μm	Y = 1.02μm	J = 1.25μm	H = 1.65μm	Ks = 2.20μm	NB1.18 = 1.18μm				Visible & Infrared Survey Telescope for Astronomy VISTA (telescope) The VISTA is a reflecting telescope with a 4.1 metre mirror, located at the Paranal Observatory in Chile. It is operated by the European Southern Observatory and saw first light in December 2009...
WISE	3.4μm	4.6μm	12μm	22μm						Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer Wide-field Infrared Survey Explorer is a NASA infrared-wavelength astronomical space telescope launched on December 14, 2009, and decommissioned/hibernated on February 17, 2011 when its transmitter was turned off...
XMM-Newton OM	UVW2 = 212nm	UVM2 = 231nm	UVW1 = 291nm	U = 344nm	B = 450nm	V = 543nm				XMM-Newton XMM-Newton The XMM-Newton is an orbiting X-ray observatory launched by ESA in December 1999 on a Ariane 5 rocket...  Optical/UV Monitoring
XEST Survey	UVW2 = 212nm	UVM2 = 231nm	UVW1 = 291nm	U = 344nm	B = 450nm	V = 543nm	J = 1.25μm	H = 1.65μm	Ks = 2.15μm	Survey includes the point source of 2MASS 2MASS Observations for the Two Micron All-Sky Survey began in 1997 and were completed in 2001 at two telescopes located one each in the northern and southern hemispheres to ensure coverage of the entire sky...  with XMM-Newton OM XMM-Newton The XMM-Newton is an orbiting X-ray observatory launched by ESA in December 1999 on a Ariane 5 rocket...