WIRC Filter Transmission Profiles

    Filters available for use in WIRC are listed below. The filters are used at approximately 77K and 7 degrees angle of incidence(AOI).  Most of the manufacturer's provided transmission profiles are for 300K and 0 degrees AOI.  Both the temperature and tilt cause a shift of the filter transmission profile blueward.  Corrections for these effects have been applied to the manufacturer's supplied data where possible.

Broadband Filters
Filter
Scanned Data
Original Data
Tilt Corrected Data
Temperature Shift (298 to 77K)
Manufacturer
Note
J
J Graph



OCLI
1
H
H Graph



OCLI
1
Ks
Ks Graph
K Blocking
Ks Tilt
cut-on: - 0.6 nm
cut-off: - 0.2 nm
Barr
2


Narrowband
Filter
Scanned Zoomed Profile
Original Data (3)
Temperature & Tilt Corrected Data (4,5)
Manufacturer
Note
J-Cont
J-Cont Zoomed Graph
J-Cont Original
J -Cont Temp & Tilt
NDC

Pa-Beta
Pa-Beta Zoomed Graph
Pa-Beta Original
Pa-Beta Temp & Tilt
NDC

H-Cont
H Zoomed Graph
H-Cont Original
H-Cont Temp & Tilt
NDC

Fe-II
Fe-II Zoomed Graph
Fe-II Original
Fe-II Temp & Tilt
NDC

Br-Gamma
Br-Gamma Zoomed Graph
Br-Gamma Original
Br-Gamma Temp & Tilt
NDC

K-Cont
K Zoomed Graph
K-Cont Original
K-Cont Temp & Tilt
NDC

CO(2-O BH)
CO(2-O BH) Zoomed Graph
CO(2-O BH) Original
CO(2-O BH) Temp & Tilt
NDC



Methane Filters
Filter
Scanned Zoomed Profile
Original Data
Tilt Corrected Data
Temperature Shift
Manufacturer
Note
CH4_L
CH4_L Zoomed Graph
CH4_L Original
CH4_L Tilt
cut-on: - 13.9536 nm
cut-off: - 12.8952 nm
NDC
6
CH4_S
CH4_S Zoomed Graph
CH4_S Original
CH4_S Tilt
cut-on: - 13.9536 nm
cut-off: - 13.176 nm
NDC
6

(1) The following values are taken from the side of the filter boxes.  Although they do not match the scanned data, the graphs are representative of standard H and K transmission.

                 J Filter                        H Filter               
        SO: 14-8744-460           SO: 14-8744-460
        PO: 393 745                   PO: 393 745
        RN: 1011-534Z/541Z    RN: 563-606/607
        SN: 33                           SN: 41
        LOT: 4Z                         LOT: 7

(2) AOI for original data is 5 degrees.

(3) Original Data taken at 300K and 0 angle of incidence.

(4)  Wavelength shifts due to temperature were derived using center wavelength v. temperature data for a sample as measured by the manufacturer (see plots below).  The difference between the peak temperature (300K for narrowband filters, 293K for methane filters) and the operational temperature of 77K was taken to establish a delta wavelength.  This value was then subtracted from the reported wavelengths in the original data to establish the working wavelengths at 77K.  

(5)  Wavelength shifts due to filter tilt were made according to Ghinassi, F. et al.(A&A 386, 1157. 2002).  The degree of tilt was taken to be 7 degrees, and the filter index of refraction was estimated to be 2, as recommended in the paper.

(6) Two equations were given for temperature corrections.


More Scanned Data
Plots from NDC

Percent Transmittence vs. Wavelength(nm)
Filter
Full Continuum Profile
Temp Shift w/ Temp
J-Cont
J-Cont Full Graph
J-Cont Graph
Pa-Beta
Pa-Beta Full Graph
Pa-Beta Graph
H-Cont
H-Cont Full Graph
H-Cont Graph
Fe-II
Fe-II Full Graph
Fe-II Graph
Br-Gamma
Br-Gamma Full Graph
Br-Gamma Graph
K-Cont
K-Cont Full Graph
K-Cont Graph
CO(2-O BH)
CO(2-O BH) Full Graph
CO(2-O BH) Graph
CH4_L
CH4_L Full Graph
CH4_L Graph
CH4_S
CH4_S Full Graph
CH4_S Graph

Developed Summer 2004