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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 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
337 BATC k1051 ** Nicholas U. Mayall 4-meter Telescope Mosaic 337 BATC k1051 ** 337 BATC k1051 ** 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.
337 BATC k1051 ** Nicholas U. Mayall 4-meter Telescope Mosaic 337 BATC k1051 ** 337 BATC k1051 **
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.
390 BATC k1052 ** Nicholas U. Mayall 4-meter Telescope Mosaic 390 BATC k1052 ** 390 BATC k1052 **
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.
420 BATC k1053 ** Nicholas U. Mayall 4-meter Telescope Mosaic 420 BATC k1053 ** 420 BATC k1053 **
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.
454 BATC k1054 ** Nicholas U. Mayall 4-meter Telescope Mosaic 454 BATC k1054 ** 454 BATC k1054 **
493 BATC k1055 ** Nicholas U. Mayall 4-meter Telescope Mosaic 493 BATC k1055 ** 493 BATC k1055 ** 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.
493 BATC k1055 ** Nicholas U. Mayall 4-meter Telescope Mosaic 493 BATC k1055 ** 493 BATC k1055 **
527 BATC k1056 ** Nicholas U. Mayall 4-meter Telescope Mosaic 527 BATC k1056 ** 527 BATC k1056 ** 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.
527 BATC k1056 ** Nicholas U. Mayall 4-meter Telescope Mosaic 527 BATC k1056 ** 527 BATC k1056 **
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.
579 BATC k1057 ** Nicholas U. Mayall 4-meter Telescope Mosaic 579 BATC k1057 ** 579 BATC k1057 **
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.
607 BATC k1058 ** Nicholas U. Mayall 4-meter Telescope Mosaic 607 BATC k1058 ** 607 BATC k1058 **
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.
666 BATC k1059 ** Nicholas U. Mayall 4-meter Telescope Mosaic 666 BATC k1059 ** 666 BATC k1059 **
705 BATC k1060 ** Nicholas U. Mayall 4-meter Telescope Mosaic 705 BATC k1060 ** 705 BATC k1060 ** 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.
705 BATC k1060 ** Nicholas U. Mayall 4-meter Telescope Mosaic 705 BATC k1060 ** 705 BATC k1060 **
755 BATC k1061 ** Nicholas U. Mayall 4-meter Telescope Mosaic 755 BATC k1061 ** 755 BATC k1061 ** 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.
755 BATC k1061 ** Nicholas U. Mayall 4-meter Telescope Mosaic 755 BATC k1061 ** 755 BATC k1061 **
802 BATC k1062 ** Nicholas U. Mayall 4-meter Telescope Mosaic 802 BATC k1062 ** 802 BATC k1062 ** 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.
802 BATC k1062 ** Nicholas U. Mayall 4-meter Telescope Mosaic 802 BATC k1062 ** 802 BATC k1062 **
815 815_v1 k1026 70.36 8152.10 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026 815 815_v1 k1026 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:In December 2003 a replacement for this filter (k1046) was purchased. See below for a comparison between the two filters.
815 815_v1 k1026 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026 815 815_v1 k1026
815 815_v1 k1026 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026 A comparison of this filter with the newer version of this filter (k1046):
815 815_v1 k1026 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026
815 815_v1 k1026 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026 815 815_v1 k1026 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=8087A, FWHM=71A, PEAK TRANSMISSION=93%.
815 815_v2 k1046 68.53 8152.64 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v2 k1046 815 815_v2 k1046 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 is a replacement for the old Rhoads 815 filter (k1026)
815 815_v2 k1046 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v2 k1046 815 815_v2 k1046
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):
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
823 823_v1 k1027 70.61 8232.04 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027 823 823_v1 k1027 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: In December 2003 a replacement for this filter (k1047) was purchased. See below for a comparison of the two filters.
823 823_v1 k1027 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027 823 823_v1 k1027
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):
823 823_v1 k1027 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027
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%.
823 823_v2 k1047 68.02 8238.79 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v2 k1047 823 823_v2 k1047 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 is a replacement of the old Rhoads 823 filter (k1027) was purchased. See below for a comparison of the two filters.
823 823_v2 k1047 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v2 k1047 823 823_v2 k1047
823 823_v2 k1047 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v2 k1047 A comparison of this filter with the newer version (k1047):
823 823_v2 k1047 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v2 k1047 823 823_v2 k1047 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= 8193.49A FWHM= 68.30A PEAK TRANSMISSION= 89.71% at 8182A
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.
848 BATC k1063 ** Nicholas U. Mayall 4-meter Telescope Mosaic 848 BATC k1063 ** 848 BATC k1063 **
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.
918 BATC k1064 ** Nicholas U. Mayall 4-meter Telescope Mosaic 918 BATC k1064 ** 918 BATC k1064 **
918R 918R_v1 k1028 Nicholas U. Mayall 4-meter Telescope Mosaic 918R 918R_v1 k1028 918R 918R_v1 k1028
918R 918R_v1 k1028 Nicholas U. Mayall 4-meter Telescope Mosaic 918R 918R_v1 k1028
918R 918R_v1 k1028 Nicholas U. Mayall 4-meter Telescope Mosaic 918R 918R_v1 k1028 918R 918R_v1 k1028 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=9140A, FWHM=81A, PEAK TRANSMISSION=84.7%.
918R 918R_v1 k1028 81.22 9210.96 Nicholas U. Mayall 4-meter Telescope Mosaic 918R 918R_v1 k1028 918R 918R_v1 k1028 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.
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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