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  5. MOSAIC Filters

MOSAIC Filters

The Mosaic II imager, used at the Blanco 4-m prime focus, takes filters that are 146x146 mm and 12 mm (nominal) thick. A set of standardized filter names and IDs for both Mosaic I on the KPNO Mayall and Mosaic II on the CTIO Blanco have been developed to ensure proper application of astrometric solutions and real-time display processing (as well as future archive uniformity). These official names are listed in the Mosaic filter list web page.

Focus offsets are referred to the R filter, since this is the filter we use for taking focus frames each night when the Mosaic is installed in order to monitor telescope performance.
Note that the Sloan set (griz) and the Johnson-Cousins BVR (but not I) sets should be near-identical to those at KPNO.

Note: The central wavelength of narrow band filters (actually all filters, but it is very significant for narrow band filters) is shifted  approx. 15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelengths quoated below are nominally for when the filters used at PF, with the approx. 15A shift included. Furthermore, the filter transmission curves presented below show the simulated filter tranmission curve for the Blanco 4m + PFADC f/2.87 beam.

Note: The Blanco prime focus corrector has poor response in the UV: 90% (4000A), 85% (3800A), 74% (3650A), 54% (3500A), 31% (3400A), 11% (3350A), 0% (3300A). These are calculations from the glass types and AR coating specifications, and the figures for 3300-3400A are rather uncertain. YOU STRONGLY ENCOURAGED TO USE THE u(SDSS) filter rather than the U filter. Neither of these filters, in combination with the CCDs and optical corrector, match the standard passbands perfectly. The U filter uses a (troublesome!) copper sulphate solution as red blocker, whereas the SDSS u filter is an interference filter.

 

Mosaic

Filter FWHM (Å) CWL (Å) Telescope Instrument Plot Data Comments
848 BATC k1063 ** Nicholas U. Mayall 4-meter Telescope Mosaic 848 BATC k1063 ** 848 BATC k1063 ** Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
823 823_v1 k1027 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027
390 BATC k1052 ** Nicholas U. Mayall 4-meter Telescope Mosaic 390 BATC k1052 ** 390 BATC k1052 **
VR Bernstein k1040 *** Retired! Nicholas U. Mayall 4-meter Telescope Mosaic VR Bernstein k1040 *** Retired! VR Bernstein k1040 *** Retired! Below is a plot of the transmission of this filter when used at telescopes with differing focal ratios and central obscurations; the KPNO 4m (f/3.1), the CTIO 4m (f/2.9), and the WIYN 0.9m (f/7.9). At the KPNO 4m f/3.1 the properties of this filter are: CWL=5934A, FWHM=2079A, PEAK TRANSMISSION=95.3%.
607 BATC k1058 ** Nicholas U. Mayall 4-meter Telescope Mosaic 607 BATC k1058 ** 607 BATC k1058 ** Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
Bw NDWFS k1025 Nicholas U. Mayall 4-meter Telescope Mosaic Bw NDWFS k1025 Bw NDWFS k1025
815 815_v2 k1046 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v2 k1046 815 815_v2 k1046
848 BATC k1063 ** Nicholas U. Mayall 4-meter Telescope Mosaic 848 BATC k1063 ** 848 BATC k1063 **
ha12 H-alpha+12nm k1012 Nicholas U. Mayall 4-meter Telescope Mosaic ha12 H-alpha+12nm k1012 ha12 H-alpha+12nm k1012 Below is a plot of the transmission of this filter when used at telescopes with differing focal ratios and central obscurations; the KPNO 4m (f/3.1), the CTIO 4m (f/2.9), and the WIYN 0.9m (f/7.9). At the KPNO 4m f/3.1 the properties of this filter are: CWL=6672A, FWHM=83A, PEAK TRANSMISSION=87.3%.
823 823_v1 k1027 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027 823 823_v1 k1027 Below is a plot of the transmission of this filter when used at telescopes with differing focal ratios and central obscurations; the KPNO 4m (f/3.1) and the CTIO 4m (f/2.9). At the KPNO 4m the properties of this filter are: CWL=8170A, FWHM=71A, PEAK TRANSMISSION=91.5%.
420 BATC k1053 ** Nicholas U. Mayall 4-meter Telescope Mosaic 420 BATC k1053 ** 420 BATC k1053 ** Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
V Harris k1003 Nicholas U. Mayall 4-meter Telescope Mosaic V Harris k1003 V Harris k1003
607 BATC k1058 ** Nicholas U. Mayall 4-meter Telescope Mosaic 607 BATC k1058 ** 607 BATC k1058 **
M Washington k1007 Nicholas U. Mayall 4-meter Telescope Mosaic M Washington k1007 M Washington k1007 Below is a plot of the transmission of this filter when used at telescopes with differing focal ratios and central obscurations; the KPNO 4m (f/3.1), the CTIO 4m (f/2.9), and the WIYN 0.9m (f/7.9). At the KPNO 4m f/3.1 the properties of this filter are: CWL=5168A, FWHM=1126A, PEAK TRANSMISSION=86.5%.
Bw NDWFS k1025 Nicholas U. Mayall 4-meter Telescope Mosaic Bw NDWFS k1025 Bw NDWFS k1025 Below is a plot of the transmission of this filter when used at telescopes with differing focal ratios and central obscurations; the KPNO 4m (f/3.1) and the CTIO 4m (f/2.9). At the KPNO 4m f/3.1 the properties of this filter are: CWL=4091A, FWHM=1250A, PEAK TRANSMISSION=91.7%.
815 815_v2 k1046 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v2 k1046 A comparison of this filter with the older version of this filter (k1026):
918 BATC k1064 ** Nicholas U. Mayall 4-meter Telescope Mosaic 918 BATC k1064 ** 918 BATC k1064 ** Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
420 BATC k1053 ** Nicholas U. Mayall 4-meter Telescope Mosaic 420 BATC k1053 ** 420 BATC k1053 **
V Harris k1003 Nicholas U. Mayall 4-meter Telescope Mosaic V Harris k1003
Un Steidel k1041 Nicholas U. Mayall 4-meter Telescope Mosaic Un Steidel k1041 Un Steidel k1041
666 BATC k1059 ** Nicholas U. Mayall 4-meter Telescope Mosaic 666 BATC k1059 ** 666 BATC k1059 ** Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
815 815_v2 k1046 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v2 k1046 815 815_v2 k1046 Below is a plot of this filter as simulated in different f/ratio beams. At the KPNO 4m f/3.1 the properties of this filter are: CWL= 8109.85A FWHM= 68.62A PEAK TRANSMISSION= 81.42% at 8122A
918 BATC k1064 ** Nicholas U. Mayall 4-meter Telescope Mosaic 918 BATC k1064 ** 918 BATC k1064 **
ha16 H-alpha+16nm k1013 Nicholas U. Mayall 4-meter Telescope Mosaic ha16 H-alpha+16nm k1013 ha16 H-alpha+16nm k1013 Below is a plot of the transmission of this filter when used at telescopes with differing focal ratios and central obscurations; the KPNO 4m (f/3.1), the CTIO 4m (f/2.9), and the WIYN 0.9m (f/7.9). At the KPNO 4m f/3.1 the properties of this filter are: CWL=6705A, FWHM=81A, PEAK TRANSMISSION=91.7%.
918R 918R_v1 k1028 Nicholas U. Mayall 4-meter Telescope Mosaic 918R 918R_v1 k1028 918R 918R_v1 k1028
454 BATC k1054 ** Nicholas U. Mayall 4-meter Telescope Mosaic 454 BATC k1054 ** 454 BATC k1054 ** Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
wrc3 WR CIII k1021 Nicholas U. Mayall 4-meter Telescope Mosaic wrc3 WR CIII k1021 wrc3 WR CIII k1021 Below is a plot of this filter as simulated in different f/ratio beams. At the KPNO 4m f/3.1 the properties of this filter are: CWL=4657A FWHM=52.6A PEAK TRANSMISSION=68.23%
666 BATC k1059 ** Nicholas U. Mayall 4-meter Telescope Mosaic 666 BATC k1059 ** 666 BATC k1059 **
Un Steidel k1041 562.72 3479.17 Nicholas U. Mayall 4-meter Telescope Mosaic Un Steidel k1041 Un Steidel k1041 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
Ud Dey custom U k1045 329.76 3485.23 Nicholas U. Mayall 4-meter Telescope Mosaic Ud Dey custom U k1045 Ud Dey custom U k1045 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
U k1001 630.71 3552.00 Nicholas U. Mayall 4-meter Telescope Mosaic U k1001 U k1001 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
U c6001 650.00 3570.00 Nicholas U. Mayall 4-meter Telescope Mosaic U c6001 U c6001 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
u SDSS c6022 400.00 3600.00 Nicholas U. Mayall 4-meter Telescope Mosaic u SDSS c6022 u SDSS c6022 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
Us solid U k1044 588.20 3651.81 Nicholas U. Mayall 4-meter Telescope Mosaic Us solid U k1044 Us solid U k1044 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
o2 OII c6012 50.00 3727.00 Nicholas U. Mayall 4-meter Telescope Mosaic o2 OII c6012 o2 OII c6012 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
C Washington c6029 1075.00 3850.00 Nicholas U. Mayall 4-meter Telescope Mosaic
C Washington k1006 1034.00 3860.00 Nicholas U. Mayall 4-meter Telescope Mosaic C Washington k1006 C Washington k1006 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer. See the plot at the bottom of the page.
Bw NDWFS k1025 1275.21 4110.78 Nicholas U. Mayall 4-meter Telescope Mosaic Bw NDWFS k1025 Bw NDWFS k1025 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer. See the plot at the bottom of the page. Note: This filter was called the NDWFS UB filter in 1997-1998.
Bj Tyson c6024 *** Not Available 1650.00 4350.00 Nicholas U. Mayall 4-meter Telescope Mosaic Bj Tyson c6024 *** Not Available Bj Tyson c6024 *** Not Available Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
B Harris c6002 990.00 4360.00 Nicholas U. Mayall 4-meter Telescope Mosaic B Harris c6002 B Harris c6002 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
B Harris k1002 993.88 4381.00 Nicholas U. Mayall 4-meter Telescope Mosaic B Harris k1002 B Harris k1002 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
wrc3 WR CIII k1021 51.71 4666.15 Nicholas U. Mayall 4-meter Telescope Mosaic wrc3 WR CIII k1021 wrc3 WR CIII k1021 Note that there is a shift in central wavelength when placed in different f/ratio beams.At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer. See the plot at the bottom of the page.
wrhe2 WR HeII k1023 50.31 4702.60 Nicholas U. Mayall 4-meter Telescope Mosaic wrhe2 WR HeII k1023 wrhe2 WR HeII k1023 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer. See the plot at the bottom of the page.
gd DECam k1035 *** New! 1524.00 4744.90 Nicholas U. Mayall 4-meter Telescope Mosaic gd DECam k1035 *** New! gd DECam k1035 *** New! Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
g SDSS k1017 1395.73 4750.58 Nicholas U. Mayall 4-meter Telescope Mosaic g SDSS k1017 g SDSS k1017 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
wr475 WR 475 k1022 51.27 4764.00 Nicholas U. Mayall 4-meter Telescope Mosaic wr475 WR 475 k1022 wr475 WR 475 k1022 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer. See the plot at the bottom of the page.
g SDSS c6017 1537.00 4813.00 Nicholas U. Mayall 4-meter Telescope Mosaic g SDSS c6017 g SDSS c6017 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
Gn Steidel k1042 762.13 4819.66 Nicholas U. Mayall 4-meter Telescope Mosaic Gn Steidel k1042 Gn Steidel k1042 Note that there is a shift in central wavelength when placed in different f/ratio beams. At the KPNO 4meter f/3.1 beam this corresponds to a shift of approximately 12 Angstroms bluer; at the CTIO 4meter f/2.9 this corresponds to a shift of approximately 15 Angstroms bluer; at the WIYN 0.9m f/7.9 this corresponds to a shift of approximately 5 Angstroms bluer.
o3 OIII c6014 50.00 4990.00 Nicholas U. Mayall 4-meter Telescope Mosaic o3 OIII c6014 o3 OIII c6014 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
M Washington c6007 1020.00 5020.00 Nicholas U. Mayall 4-meter Telescope Mosaic M Washington c6007 M Washington c6007 Note: The central wavelength of CTIO Mosaic narrow band filters (actually all filters, but is very significant for narrow band filters) is shifted ~15A to the BLUE in the f/2.87 beam of the Blanco 4m + PFADC corrector as compared to the transmission measured in parallel light. The central wavelength quoted below is nominally for when the filter is used at PF, with the ~15A shift included. Furthermore, the filter transmission curve presented below shows the simulated filter transmission curve for the Blanco 4m + PFADC f/2.87 beam.
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Last updated: 2009 Dec 9, ARW

 

Staff Contacts:
Sean Points: spointsATctio.noao.edu
Alistair Walker: awalkerATctio.noao.edu

Updated on June 5, 2021, 8:00 pm