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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.  Click here to download a .zip file containing all available transmission curve data.

The 1%, 4%, and 5% methane filters are used for Simultaneous Spectral Differential Imaging (SSDI) in the methane bandhead. These filters were built to high precision specifications for optimal image quality.  The 1% and 4% filters are mounted in both filter wheels so they can be interchanged to help cancel non-common-path errors between the two science channels.

The H20 Ice L filter was provided by a principal investigator. 

The remaining filters are from the same batch as the NIRI filters.

The following table lists the available filters.  Entries with a Gemini ID number indicate the installed filters for the individual channels. If the entry is blank, the filter is not installed in that channel.

 


NICI Filters
Filter Name Central Wavelength Wavelength range or Width Channel 1
(Red)
Gemini ID
Channel 2
(Blue)
Gemini ID
Note
Block -- -- -- --
CH4 H 1% S
1.587 0.0150 (0.94%) G0724
G0722
CH4 H 1% Sp 1.603 0.0162 (1.01%) G0728
G0726
CH4 H 1% L 1.628 0.0174 (1.07%) G0720
G0732
CH4 H 1% L_2 1.628 0.0174 (1.07%) G0735
 
CH4 H 4% S 1.578 0.062 (4.00%) G0742
G0743
CH4 H 4% L 1.652 0.066 (3.95%) G0740
G0737
CH4 K 5% S
2.080 0.105 (5.06%)   G0746
CH4 K 5% L
2.241 0.107 (4.84%) G0748   
H20 Ice L
3.09 3.02 - 3.15 G0715 
J
1.25 1.15-1.33   G0702
H 1.65 1.49-1.78   G0703
K 2.20 2.03-2.36 G0704  
Ks 2.15 1.99-2.30 G0705  
Kprime 2.12 1.95-2.30 G0706  
Lprime 3.78 3.43-4.13 G0707   Must be used w/ H50/50 to reduce bgd.
Mprime 4.68 4.55-4.79 G0708   Installed, but not available due to saturation.
[Fe II] 1.644 1.5%   G0712
H2 1-0 S(1) 2.1239 1.23%   G0709 
Br-gamma 2.1686 1.36%   G0711
Kcont 2.2718 1.55% G0710  
CH4 H 6.5% S 1.596 0.1175 (7.3%)     G0713
CH4 H 6.5% L 1.701 0.0972 (5.7%) G0714