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  4. MOSAIC Filters
  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 transmission 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
B Harris k1002 Nicholas U. Mayall 4-meter Telescope Mosaic B Harris k1002 B Harris k1002
579 BATC k1057 ** Nicholas U. Mayall 4-meter Telescope Mosaic 579 BATC k1057 ** 579 BATC k1057 ** 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.
wrc4 WR CIV k1024 Nicholas U. Mayall 4-meter Telescope Mosaic wrc4 WR CIV k1024 wrc4 WR CIV k1024 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=5819A FWHM=42.17A PEAK TRANSMISSION=71.36%
Ud Dey custom U k1045 Nicholas U. Mayall 4-meter Telescope Mosaic Ud Dey custom U k1045 Ud Dey custom U k1045
802 BATC k1062 ** Nicholas U. Mayall 4-meter Telescope Mosaic 802 BATC k1062 ** 802 BATC k1062 **
ha8 H-alpha+8nm k1011 Nicholas U. Mayall 4-meter Telescope Mosaic ha8 H-alpha+8nm k1011 ha8 H-alpha+8nm k1011 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=6634A, FWHM=81A, PEAK TRANSMISSION=89.2%.
823 823_v1 k1027 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027 A comparison of this filter with the newer version (k1047):
390 BATC k1052 ** Nicholas U. Mayall 4-meter Telescope Mosaic 390 BATC k1052 ** 390 BATC k1052 ** 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.
B Harris k1002 Nicholas U. Mayall 4-meter Telescope Mosaic B Harris k1002
579 BATC k1057 ** Nicholas U. Mayall 4-meter Telescope Mosaic 579 BATC k1057 ** 579 BATC k1057 **
C Washington k1006 Nicholas U. Mayall 4-meter Telescope Mosaic C Washington k1006 C Washington k1006 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=3892A, FWHM=1030A, PEAK TRANSMISSION=77.4%.
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 **
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Last updated: 2009 Dec 9, ARW

 

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

Updated on May 14, 2024, 1:18 pm