IRIM Filter and Linearity Plots

Current Population of IRIM Filter Wheel

IRIM Filters (08 July 1999)

Position	Name	cuton	cutoff	Comments
1	DARK	...	...	Cold dark slide
2	2.12	2.110	2.128	1% Bandpass S(1) H₂
3	1.281	1.275	1.287	1% Bandpass Pa beta
4	2.16	2.150	2.172	1% Bandpass Br gamma
5	J	1.095	1.38	Barr lot 0492
6	H	1.51	1.79	Barr lot 0492
7	K'	1.99	2.32	Barr lot 1292
8	K	2.03	2.42	Barr lot 1090

Notes on filters:

The narrowband filters are matched in bandpass and wedged to decrease fringing from night sky lines.
Narrowband filters may be changed on occasion to accommodate specific observing runs. The broadband filters will not, in general, be switched out.
The broadband filters are chosen to match those in SQIID and COB.
Note the K' bandpass includes very little of the CO overtone absorption band long of 2.29 microns.

IRIM Plots

ASCII listings of the transmission vs wavelength for the individual IRIM filters may be obtained by anonymous ftp from the subdirectory kpno/filters/IRdata. The files are named IRIMJ, IRIMH,... Except for the K' filter, these traces are from vendor-supplied plots with the filter at 77 K. The K' filter curve was shifted 2% shortward to approximate the wavelength shift which occurs when the filter is cooled to 77 K.

Individual PostScript files of the filter transmission curves may also be retrieved from the subdirectory /kpno/filters/IRplots.

rjoyce@noao.edu
12 July 1999