The leftmost column contains the command name. The following two columns show the filter combination's central wavelength and FWHM. Next are the two filter wheel positions (inner and outer). The sixth column gives an estimate of the background rate in electrons/sec (using 6 electrons/DN). This of course can vary from night to night, and position in the sky. The seventh column gives an estimate of the sensitivity, in the form of a "zero-point" magnitude. This is 2.5 times the log (base 10) of the number of electrons/sec expected from a zeroth magnitude star. Note that standard star measurements exist only for standard passbands; all other estimates (shown in italics) are approximate. Also note that atmospheric conditions will cause the apparent sensitivity to vary from night to night. The icons in the last column link to plots of the individual filter passbands.

Macro	Wavelength		FWI	FWO	Background	Sensitivity	Plot?
CMD	Central	FWHM	Pos	Pos	electrons/sec
Broad-Band Filters
z	1.03225	0.1565	2	19
j	1.251	0.292	3	10	2000	28.13
jh	1.30	0.60	1	10
h	1.6575	0.333	4	10	6400	27.80
hk	1.967	1.13	9	19
kp	2.1235	0.337	6	19	3800	26.92
ks	2.155	0.33	7	19	3600	26.78
k	2.2135	0.427	8	19	7200	27.16
kw	2.249	0.594	10	19	30,000	27.50
ch4	2.269	0.155	5	10
ls	2.9785	1.023	12	19	3,200,000*	26.62
kl	3.1475	2.003	14	19
lw	3.492	1.490	15	19	45,000,000	26.94
lp	3.831	0.620	13	19	9,700,000*	26.24
lm	3.945	2.002	17	19
m	4.718	0.628	16	19	95,000,000	24.87
mw	5.022	1.356	18	19
Thermal Blocking Filters
uv22i	1.45	2.5	11	19
uv22o	1.45	2.5	19	10
Narrow-Band Filters
hei	1.0829	0.0136	19	0	49	24.70
pgamma	1.0930	0.0104	11	1	47	24.62
oii	1.23605	0.0105	19	2	86	24.31
pbeta	1.2823	0.0146	11	3	350	24.72
feii	1.6471	0.0176	11	4	330	24.12
h210	2.12495	0.0235	11	11	150	22.98
brgamma	2.1647	0.0224	11	12	200	23.21
h221	2.24855	0.0239	11	13	138	22.95
kcont	2.25965	0.0531	19	15	570	24.43
co20	2.2973	0.0274	19	14	240	23.41
pahcs	3.0825	0.1007	19	16	285,000	24.25
pah	3.3100	0.063	19	17	540,000	23.53
pahl	3.4128	0.0734	19	18	490,000	23.92
bralphacont	3.9923	0.0483	19	5	930,000	23.51
bralpha	4.0455	0.0524	19	6	1,320,000	23.40

* Empirical fits of the background rate as a function of airmass, AM:

Background rate in Ls = (1.8 * AM + 1.4) x 10^6 electrons/sec

Background rate in L' = (2.8 * AM + 6.9) x 10^6 electrons/sec

Remember in these formulae that AM is always greater than or equal to 1!

These formulae can be interpreted as a sky background rate, which depends on AM, and a telescope+instrument background rate, which is independent of AM.

Last Update: 1/29/98

Name: Bob Goodrich