Central wavelengths and zero points

Here is a large collection of central wavelengths and zero points, useful for converting between flux densities and magnitudes, which then enables adding points into an SED, or making a color-mag diagram (depending on whether you are starting from mags or flux densities).

band     wavelength (um)    zero point (Jy)
 J            1.235          1594
 H            1.662          1024
 Ks           2.159            666.7  Kshort not Johnson K!  http://www.ipac.caltech.edu/2mass/releases/allsky/doc/sec6_4a.html

(note that http://irsa.ipac.caltech.edu/Missions/2mass.html has/had 2.17 um, which isn't right)

 I1           3.6             280.9    http://irsa.ipac.caltech.edu/Missions/spitzer.html
 I2           4.5             179.7
 I3           5.8             115.0
 I4           8.0              64.13
 M1           24                7.14
 M2           70                0.775
 M3          160                0.159

 W1           3.4             309.54      http://irsa.ipac.caltech.edu/Missions/wise.html
 W2           4.6             171.79
 W3          12                31.676
 W4          22                 8.3635

 U           0.36            1755
 B           0.44            4000.87
 V           0.55            3597.28
 Rc          0.71            3080     !! Cousins R (not the same as Johnson R)!
 Ic          0.79            2432.84  !! Cousins I (not the same as Johnson I)!

 sloan u    2910*1d-4        see below    !! 2910 A, and there are 10^-4 um per A. (etc for rest)
 sloan g    4810*1d-4
 sloan r    6230*1d-4
 sloan i    7640*1d-4
 sloan z    9060*1d-4

 ukidss Z      0.8817        2232 ?             Hewett 2006, MNRAS, 367, 454
 ukidss Y      1.0305        2026 ?
 ukidss J      1.2483        1530 ?
 ukidss H      1.6313        1019 ?
 ukidss K      2.2010         631 ?

 iphas rprime  0.624         3173.3
 iphas ha      0.656         2974.4
 iphas iprime  0.774         2515.7 

 denis i       0.778         2499              Fouque et al. 2000, A&AS, 141, 313
 denis J       1.221         1595
 denis Ks      2.144          665 

 akari band 1   9                   !! Akari reports things already in flux densities. 
 akari band 2  18                      Generally, don't trust any other Akari bands, unless you are sure the source is really there.

 IRAS band 1   12              28.3        http://irsa.ipac.caltech.edu/IRASdocs/exp.sup/ch6/C2a.html
 IRAS band 2   25               6.73
 IRAS band 3   60               1.19
 IRAS band 4  100               0.43 

 MSX Band A     7.76                        http://irsa.ipac.caltech.edu/data/MSX/docs/MSX_psc_es.pdf for 10,000K BB
 MSX Band B1    4.29                  !! MSX should already be in flux density
 MSX Band B2    4.35
 MSX Band C    11.99
 MSX Band D    14.55
 MSX Band E    20.68

BE CAREFUL to keep track of whether you are working with Vega-based magnitudes or AB mags. Vega magnitudes define things with respect to a Vega spectrum (see Units page), but some folks (largely extragalactic folks) define things with respect to a flat spectrum source instead, and those are AB mags. Most Sloan folks (even those folks working with stars) work in AB mags instead. For AB mags, you always use a flat reference spectrum, so the zero point is 3631 Jy for all bands.

More on filters and bandpasses

For advanced folks (and, frankly, my own future reference): If you have measurements from one of the USNO plate scans of the POSS plates... Monet et al. 2003, AJ, 125, 984 reports these transformations from SDSS EDR photometry [Section 8. eqn 2b-2e].

"B" magnitudes:
O = g* + 0.08 + 0.452(g* -r*), sigma = 0.34
J = g* + 0.06 + 0.079(g* - r*), sigma = 0.33
"R" magnitudes:
E = r* - 0.20 - 0.086(g* - r*), sigma = 0.30
F = r* - 0.09 - 0.109(g* - r*), sigma = 0.26
"I" magnitudes:
N = i* - 0.44 -0.164(r* -i*), sigma =0.31

Thanks to Peregrine McGehee for the following inversion of these formulae:

   g* - r * = ([Bmag - Rmag]  +0.22)/1.37
   g* = Bmag - 0.07 - 0.27(g* - r*)
   r* = g* - (g* - r*)
   i* = (Imag - 0.44 +0.16r* )/1.16