In astronomy, a photometric system is a set of well-defined passbands (or optical 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 is provided.

A commonly adopted standardized photometric system is the Johnson-Morgan or UBV photometric system (1953). At present, there are more than 200 photometric systems.[citation needed]

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

Photometric letters

Each letter designates a section of light of the electromagnetic spectrum; these cover well the consecutive major groups, near-ultraviolet (NUV), visible light (centered on the V band), near-infrared (NIR) and part of mid-infrared (MIR).[a] The letters are not standards, but are recognized by common agreement among astronomers and astrophysicists.

The use of U,B,V,R,I bands dates from the 1950s, being single-letter abbreviations.[b]

With the advent of infrared detectors in the next decade, the J to N bands were labelled following on from near-infrared's closest-to-red band, I.

Later the H band was inserted, then Z in the 1990s and finally Y, without changing earlier definitions. Hence, H is out of alphabetical order from its neighbours, while Z,Y are reversed from the alphabetical – higher-wavelength – sub-series which dominates current photometric bands.

Filter
Letter
Effective Wavelength Midpoint
λeff for Standard Filter[2]
Full width at half maximum[2]
[c] (archetypal Bandwidth) (Δλ)[d]
Variant(s) Description
Ultraviolet
U 365 nm 66 nm u, u', u* "U" stands for ultraviolet.
Visible
B 445 nm 94 nm b "B" stands for blue.
G[3] 464 nm 128 nm g, g' "G" stands for green.
V 551 nm 88 nm v, v' "V" stands for visual.
R 658 nm 138 nm r, r', R', Rc, Re, Rj "R" stands for red.
Near-Infrared
I 806 nm 149 nm i, i', Ic, Ie, Ij "I" stands for infrared.
Z 900 nm[4] 152 nm z, z'
Y 1020 nm 120 nm y
J 1220 nm 213 nm J', Js
H 1630 nm 307 nm
K 2190 nm 390 nm K Continuum, K', Ks, Klong, K8, nbK
L 3450 nm 472 nm L', nbL'
Mid-Infrared
M 4750 nm 460 nm M', nbM
N 10500 nm 2500 nm
Q 21000 nm[5] 5800 nm[5] Q'

Note: colors are only approximate and based on wavelength to sRGB representation (when possible).[6]

Combinations of these letters are frequently used; for example the combination JHK has been used more or less as a synonym of "near-infrared", and appears in the title of many papers.[7]

Filters used

The filters currently being used by other telescopes or organizations.

Units of measurements:

Name Filters Link
2.2 m telescope at La Silla, ESO J = 1.24 μm H = 1.63 μm K = 2.19 μm L' = 3.78 μm M = 4.66 μm N1 = 8.36 μm N2 = 9.67 μm N3 = 12.89 μm 2.2 m telescope at La Silla, ESO[8]
2MASS/PAIRITEL J = 1.25 μm H = 1.65 μm Ks = 2.15 μm Two Micron All-Sky Survey, Peters Automated InfraRed Imaging TELescope
CFHTLS (Megacam) u* = 374 nm g' = 487 nm r' = 625 nm i' = 770 nm z' = 890 nm Canada-France-Hawaii Telescope
Chandra X-ray Observatory LETG = 0.08-0.2 keV HETG = 0.4-10 keV Chandra X-ray Observatory
CTIO J = 1.20 μm H = 1.60 μm K = 2.20 μm L = 3.50 μm Cerro Tololo Inter-American Observatory, a division of NOAO
Cousins RI photometry Rc = 647 nm Ic = 786.5 nm Cousins RI photometry, 1976[9]
the Dark Energy Camera g = 472.0 nm r = 641.5 nm i = 783.5 nm z = 926.0 nm Y = 1009.5 nm Central wavelengths for bands in the Dark Energy Survey[10]
DENIS I = 0.79 μm J = 1.24 μm K = 2.16 μm Deep Near Infrared Survey
Eggen RI photometry Re = 635 nm Ie = 790 nm Eggen RI photometry, 1965[11]
FIS N60 = 65.00 μm WIDE-S = 90.00 μm WIDE-L = 145.00 μm N160 = 160.00 μm Far-Infrared Surveyor on board, AKARI space telescope
Gaia G = 673 nm GBP = 532 nm GRP = 797 nm GRVS = 860 nm Gaia (spacecraft)[12]
GALEX[13] NUV = 175–280 nm FUV = 135–175 nm GALaxy Evolution Explorer
GOODS (Hubble ACS) B = 435 nm V = 606 nm i = 775 nm z = 850 nm Advanced Camera for Surveys on the Hubble Space Telescope
HAWC+ Band 1 = 53 μm Band 2 = 89 μm Band 3 = 154 μm Band 4 = 214 μm High-resolution Airborne Wideband Camera+ for SOFIA[14]
HDF 450 nm 606 nm 814 nm Hubble Deep Field from the Hubble Space Telescope
IRTF NSFCAM J = 1.26 μm H = 1.62 μm K' = 2.12 μm Ks = 2.15 μm K = 2.21 μm L = 3.50 μm L' = 3.78 μm M' = 4.78 μm M = 4.85 μm NASA Infrared Telescope Facility NSFCAM[15]
ISAAC UTI/VLT[16] Js = 1.2 μm H = 1.6 μm Ks = 2.2 μm L = 3.78 μm Brα = 4.07 μm Infrared Spectrometer And Array Camera at Very Large Telescope
Johnson system (UBV) U = 364 nm B = 442 nm V = 540 nm UBV photometric system
Vera C. Rubin Observatory (LSST)[17] u = 320.5–393.5 nm g = 401.5–551.9 nm r = 552.0–691.0 nm i = 691.0–818.0 nm z = 818.0–923.5 nm y = 923.8–1084.5 nm Vera C. Rubin Observatory
OMC Johnson V-filter = 500-580 nm Optical Monitor Camera[18] on INTEGRAL
Pan-STARRS g = 481 nm r = 617 nm i = 752 nm z = 866 nm y = 962 nm Panoramic Survey Telescope And Rapid Response System[19]
ProNaOS/SPM Band 1 = 180-240 μm Band 2 = 240-340 μm Band 3 = 340-540 μm Band 4 = 540-1200 μm PROgramme NAtional d'Observations Submillerètrique/Systéme Photométrique Multibande, balloon-borne experiment[20]
Sloan, SDSS u' = 354 nm g' = 475 nm r' = 622 nm i' = 763 nm z' = 905 nm Sloan Digital Sky Survey
SPIRIT III Band B1 = 4.29 μm Band B2 = 4.35 μm Band A = 8.28 μm Band C = 12.13 μm Band D = 14.65 μm Band E = 21.34 μm Infrared camera on Midcourse Space Experiment[21]
Spitzer IRAC ch1 = 3.6 μm ch2 = 4.5 μm ch3 = 5.8 μm ch4 = 8.0 μm Infrared Array Camera on Spitzer Space Telescope
Spitzer MIPS 24 μm 70 μm 160 μm Multiband Imaging Photometer for Spitzer on Spitzer
Stromvil filters U = 345 nm P = 374 nm S = 405 nm Y = 466 nm Z = 516 nm V = 544 nm S = 656 nm Stromvil photometry
Strömgren filters u = 350 nm v = 411 nm b = 467 nm y = 547 nm β narrow = 485.8 nm β wide = 485 nm Strömgren photometric system
UKIDSS (WFCAM) Z = 882 nm Y = 1031 nm J = 1248 nm H = 1631 nm K = 2201 nm UKIRT Infrared Deep Sky Survey
Vilnius photometric system U = 345 nm P = 374 nm S = 405 nm Y = 466 nm Z = 516 nm V = 544 nm S = 656 nm Vilnius photometric system
VISTA IRC Z = 0.88 μm Y = 1.02 μm J = 1.25 μm H = 1.65 μm Ks = 2.20 μm NB1.18 = 1.18 μm Visible & Infrared Survey Telescope for Astronomy
WISE W1 = 3.4 μm W2 = 4.6 μm W3 = 12 μm W4 = 22 μm Wide-field Infrared Survey Explorer
XMM-Newton OM UVW2 = 212 nm UVM2 = 231 nm UVW1 = 291 nm U = 344 nm B = 450 nm V = 543 nm XMM-Newton Optical/UV Monitor[22]
XEST Survey UVW2 = 212 nm UVM2 = 231 nm UVW1 = 291 nm U = 344 nm B = 450 nm V = 543 nm J = 1.25 μm H = 1.65 μm Ks = 2.15 μm Survey includes the point source of 2MASS with XMM-Newton OM[23]

Note: colors are only approximate and based on wavelength to sRGB representation (when possible).[24]


See also

References and footnotes

  1. ^ Spectral Colors
  2. ^ a b Binney, J.; Merrifield M. Galactic Astronomy, Princeton University Press, 1998, ch. 2.3.2, pp. 53
  3. ^ Bessell, Michael S. (September 2005). "Standard Photometric Systems" (PDF). Annual Review of Astronomy and Astrophysics. 43 (1): 293–336. Bibcode:2005ARA&A..43..293B. doi:10.1146/annurev.astro.41.082801.100251. ISSN 0066-4146.
  4. ^ Gouda, N.; Yano, T.; Kobayashi, Y.; Yamada, Y.; et al. (23 May 2005). "JASMINE: Japan Astrometry Satellite Mission for INfrared Exploration". Proceedings of the International Astronomical Union. 2004 (IAUC196): 455–468. Bibcode:2005tvnv.conf..455G. doi:10.1017/S1743921305001614. S2CID 123261288. z-band: 0.9 μm
  5. ^ a b [1] Handbook of Geophysics and the Space Environment 1985, Air Force Geophysics Laboratory, 1985, ed. Adolph S. Jursa, Ch. 25, Table 25-1
  6. ^ "Light wavelength to RGB Converter". www.johndcook.com. Retrieved 2023-07-28.
  7. ^ Monson, Andrew J.; Pierce, Michael J. (2011). "Near-Infrared (Jhk) Photometry of 131 Northern Galactic Classical Cepheids". The Astrophysical Journal Supplement Series. 193 (1): 12. Bibcode:2011ApJS..193...12M. doi:10.1088/0067-0049/193/1/12. Example of use of J for "near-infrared"
  8. ^ A study of the Chamaeleon I dark cloud and T-association. II – High-resolution IRAS maps around HD 97048 and 97300, Assendorp, R.; Wesselius, P. R.; Prusti, T.; Whittet, D. C. B., 1990
  9. ^ ADPS
  10. ^ DES
  11. ^ ADPS
  12. ^ Jordi, C.; Gebran, M.; Carrasco, J. M.; de Bruijne, J.; Voss, H.; Fabricius, C.; Knude, J.; Vallenari, A.; Kohley, R.; Mora, A. (2010). "Gaia broad band photometry". Astronomy and Astrophysics. 523: A48. arXiv:1008.0815. Bibcode:2010A&A...523A..48J. doi:10.1051/0004-6361/201015441. S2CID 34033669.
  13. ^ "GALEX Instrument Summary". Goddard Space Flight Center. Retrieved 5 June 2019.
  14. ^ "HAWC". Archived from the original on 2008-03-13. Retrieved 2008-05-25.
  15. ^ NSFCAM
  16. ^ "ISAAC Overview". Paranal Instrumentation. ESO. Retrieved 13 October 2011.
  17. ^ LSST filter characteristics taken from https://github.com/lsst/throughputs/blob/master/baseline/ (see the filter_X.dat files) with the limits at half the peak transmission.
  18. ^ About INTEGRAL
  19. ^ Tonry, J. L.; Stubbs, C. W.; Lykke, K. R.; Doherty, P.; Shivvers, I. S.; Burgett, W. S.; Chambers, K. C.; Hodapp, K. W.; Kaiser, N.; Kudritzki, R.-P.; Magnier, E. A.; Morgan, J. S.; Price, P. A.; Wainscoat, R. J. (2012). "THE Pan-STARRS1 PHOTOMETRIC SYSTEM". The Astrophysical Journal. 750 (2): 99. arXiv:1203.0297. Bibcode:2012ApJ...750...99T. doi:10.1088/0004-637X/750/2/99. S2CID 119266289.
  20. ^ Pajot, F.; Stepnik, B.; Lamarre, J.-M.; Bernard, J.-P.; Dupac, X.; Giard, M.; Lagache, G.; Leriche, B.; Meny, C.; Recouvreur, G.; Renault, J.-C.; Rioux, C.; Ristorcelli, I.; Serra, G.; Torre, J.-P. (2006). "Calibration of the PRONAOS/SPM submillimeter photometer" (PDF). Astronomy & Astrophysics. 447 (2): 769–781. Bibcode:2006A&A...447..769P. doi:10.1051/0004-6361:20034226. S2CID 4822401.
  21. ^ MSXPSC – Midcourse Space Experiment (MSX) Point Source Catalog, V2.3
  22. ^ XMM-Newton User's Handbook Sect. 3.5.3.1
  23. ^ Audard, M.; Briggs, K. R.; Grosso, N.; Güdel, M.; Scelsi, L.; Bouvier, J.; Telleschi, A. (2007). "The XMM-Newton Optical Monitor survey of the Taurus molecular cloud". Astronomy & Astrophysics. 468 (2): 379–390. arXiv:astro-ph/0611367. Bibcode:2007A&A...468..379A. doi:10.1051/0004-6361:20066320. S2CID 59479808.
  24. ^ "Light wavelength to RGB Converter". www.johndcook.com. Retrieved 2023-07-28.
  1. ^ Indigo and cyan are not standard colors.[1] Orange, yellow, and green fall under visual bands, while violet and purple are in every blue band.
  2. ^ See Description column of the chart
  3. ^ The width of the band of the curve's 50% upper values (that is, peak) for a natural curve of paradigm source of this light
  4. ^ Delta lambda