NICI Filters

NICI has one filter wheel in each science channel. The current filter complement is listed below, with the location of each filter indicated by the Gemini ID numbers in the "Channel 1" and "Channel 2" columns. Click on an ID number to see the transmission curve for the actual filter element in that channel, if available.

The 1% 1.6 µm filters are used with the H-band 50/50 beamsplitter for Simultaneous Spectral Differential Imaging (SSDI) in the methane bandhead. These filters were built to high precision specifications for optimal image quality. They are mounted in both filter wheels so they can be interchanged to help cancel non-common-path errors between the two science channels.

NICI Filters
Filter Name	Central Wavelength	Wavelength range or Width	Channel 1 (Red) Gemini ID	Channel 2 (Blue) Gemini ID
Blank-off	--	--	--	--
CH4 H 1% S	1.587	0.0150 (0.94%)	G...	G...
CH4 H 1% Sp	1.603	0.0162 (1.01%)	G...	G...
CH4 H 1% L	1.628	0.0174 (1.07%)	G...	G...
J	1.25	1.15-1.33		G...
H	1.65	1.49-1.78		G...
K	2.20	2.03-2.36	G...
Ks	2.15	1.99-2.30	G...
K'	2.12	1.95-2.30	G...
L'	3.78	3.43-4.13	G...
M'	4.68	4.55-4.79	G...
[Fe II]	1.644	1.5%		G...
H2 1-0 S(1)	2.1239	1.23%	G...
Br-gamma	2.1686	1.36%	G...
K cont	2.2718	1.55%	G...
CH4 H 6.5% S	1.596	0.1175 (7.3%)		G...
CH4 H 6.5% L	1.701	0.0972 (5.7%)	G...