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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 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
D51 DDO 51 k1008 Nicholas U. Mayall 4-meter Telescope Mosaic D51 DDO 51 k1008 D51 DDO 51 k1008 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=5132A FWHM=161A PEAK TRANSMISSION=85.1%
815 815_v1 k1026 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026 815 815_v1 k1026
973 BATC k1065 ** Nicholas U. Mayall 4-meter Telescope Mosaic 973 BATC k1065 ** 973 BATC k1065 ** 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.
918R 918R_v1 k1028 Nicholas U. Mayall 4-meter Telescope Mosaic 918R 918R_v1 k1028
454 BATC k1054 ** Nicholas U. Mayall 4-meter Telescope Mosaic 454 BATC k1054 ** 454 BATC k1054 **
R Harris k1004 Nicholas U. Mayall 4-meter Telescope Mosaic R Harris k1004 R Harris k1004
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.
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):
823 823_v2 k1047 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v2 k1047 823 823_v2 k1047
973 BATC k1065 ** Nicholas U. Mayall 4-meter Telescope Mosaic 973 BATC k1065 ** 973 BATC k1065 **
O3 OIII N2 k1014 * Nicholas U. Mayall 4-meter Telescope Mosaic O3 OIII N2 k1014 * O3 OIII N2 k1014 * 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=5006A, FWHM=56A, PEAK TRANSMISSION=76%.
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%.
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.
R Harris k1004 Nicholas U. Mayall 4-meter Telescope Mosaic R Harris k1004
wr475 WR 475 k1022 Nicholas U. Mayall 4-meter Telescope Mosaic wr475 WR 475 k1022 wr475 WR 475 k1022 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=4749A FWHM=51.32A PEAK TRANSMISSION=79.2%.
Rs Steidel k1043 Nicholas U. Mayall 4-meter Telescope Mosaic Rs Steidel k1043 Rs Steidel k1043
705 BATC k1060 ** Nicholas U. Mayall 4-meter Telescope Mosaic 705 BATC k1060 ** 705 BATC k1060 **
ha H-alpha k1009 Nicholas U. Mayall 4-meter Telescope Mosaic ha H-alpha k1009 ha H-alpha k1009 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=6550A, FWHM=80A, PEAK TRANSMISSION=93.7%.
815 815_v1 k1026 Nicholas U. Mayall 4-meter Telescope Mosaic 815 815_v1 k1026
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):
U k1001 Nicholas U. Mayall 4-meter Telescope Mosaic U k1001 U k1001
493 BATC k1055 ** Nicholas U. Mayall 4-meter Telescope Mosaic 493 BATC k1055 ** 493 BATC k1055 **
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.
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%.
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
U k1001 Nicholas U. Mayall 4-meter Telescope Mosaic U k1001
Ooff OIII+30nm k1015 Nicholas U. Mayall 4-meter Telescope Mosaic Ooff OIII+30nm k1015 Ooff OIII+30nm k1015 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=5298.69A FWHM=240.20A PEAK TRANSMISSION=91.73%
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.
I Nearly-Mould k1005 Nicholas U. Mayall 4-meter Telescope Mosaic I Nearly-Mould k1005 I Nearly-Mould k1005
wrhe2 WR HeII k1023 Nicholas U. Mayall 4-meter Telescope Mosaic wrhe2 WR HeII k1023 wrhe2 WR HeII k1023 Below is a plot of this filter as simulated in different f/ratio beams. At the KPNO 4m the properties of this filter are: CWL=4695A FWHM=51.34A PEAK TRANSMISSION=74.83%.
Us solid U k1044 Nicholas U. Mayall 4-meter Telescope Mosaic Us solid U k1044 Us solid U k1044
755 BATC k1061 ** Nicholas U. Mayall 4-meter Telescope Mosaic 755 BATC k1061 ** 755 BATC k1061 **
ha4 H-alpha+4nm k1010 Nicholas U. Mayall 4-meter Telescope Mosaic ha4 H-alpha+4nm k1010 ha4 H-alpha+4nm k1010 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=6593A, FWHM=81A, PEAK TRANSMISSION=91.1%.
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.
527 BATC k1056 ** Nicholas U. Mayall 4-meter Telescope Mosaic 527 BATC k1056 ** 527 BATC k1056 **
I Nearly-Mould k1005 Nicholas U. Mayall 4-meter Telescope Mosaic I Nearly-Mould k1005
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.
823 823_v1 k1027 Nicholas U. Mayall 4-meter Telescope Mosaic 823 823_v1 k1027 823 823_v1 k1027
337 BATC k1051 ** Nicholas U. Mayall 4-meter Telescope Mosaic 337 BATC k1051 ** 337 BATC k1051 **
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%.
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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