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
R Harris k1004 Nicholas U. Mayall 4-meter Telescope Mosaic R Harris k1004 R Harris k1004
R Harris k1004 Nicholas U. Mayall 4-meter Telescope Mosaic R Harris k1004
r SDSS c6018 1468.00 6287.00 Nicholas U. Mayall 4-meter Telescope Mosaic r SDSS c6018 r SDSS c6018 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.
r SDSS k1018 1475.17 6292.28 Nicholas U. Mayall 4-meter Telescope Mosaic r SDSS k1018 r SDSS k1018 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.
rd DECam k1036 *** New! 1426.90 6395.60 Nicholas U. Mayall 4-meter Telescope Mosaic rd DECam k1036 *** New! rd DECam k1036 *** 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.
Rs Steidel k1043 1048.78 6975.13 Nicholas U. Mayall 4-meter Telescope Mosaic Rs Steidel k1043 Rs Steidel k1043 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.
Rs Steidel k1043 Nicholas U. Mayall 4-meter Telescope Mosaic Rs Steidel k1043 Rs Steidel k1043
s2 SII c6013 80.00 6725.00 Nicholas U. Mayall 4-meter Telescope Mosaic s2 SII c6013 s2 SII c6013 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 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 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 k1001 Nicholas U. Mayall 4-meter Telescope Mosaic U k1001 U k1001
U k1001 Nicholas U. Mayall 4-meter Telescope Mosaic U k1001
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.
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.
Ud Dey custom U k1045 Nicholas U. Mayall 4-meter Telescope Mosaic Ud Dey custom U k1045 Ud Dey custom U k1045
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.
Un Steidel k1041 Nicholas U. Mayall 4-meter Telescope Mosaic Un Steidel k1041 Un Steidel k1041
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.
Us solid U k1044 Nicholas U. Mayall 4-meter Telescope Mosaic Us solid U k1044 Us solid U k1044
V Harris c6026 940.00 5370.00 Nicholas U. Mayall 4-meter Telescope Mosaic V Harris c6026 V Harris c6026 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.
V Harris k1003 948.66 5386.76 Nicholas U. Mayall 4-meter Telescope Mosaic V Harris k1003 V Harris k1003 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
V Harris k1003 Nicholas U. Mayall 4-meter Telescope Mosaic V Harris k1003
VR Bernstein k1040 *** Retired! 2119.56 5944.95 Nicholas U. Mayall 4-meter Telescope Mosaic VR Bernstein k1040 *** Retired! VR Bernstein k1040 *** Retired! NOTE: This filter was damaged in June 2011 and is retired. 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.
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%.
VR k1039 *** New! 2216.00 5940.00 Nicholas U. Mayall 4-meter Telescope Mosaic VR k1039 *** New! VR k1039 *** New! NOTE: This filter is a replacement for k1040. 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.
wh Bk-7 c6016 5000.00 6500.00 Nicholas U. Mayall 4-meter Telescope Mosaic
wh Bk-7 k1016 6800.00 5600.00 Nicholas U. Mayall 4-meter Telescope Mosaic wh Bk-7 k1016 wh Bk-7 k1016 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.
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%.
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.
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%
wrc4 WR CIV k1024 41.79 5828.71 Nicholas U. Mayall 4-meter Telescope Mosaic wrc4 WR CIV k1024 wrc4 WR CIV k1024 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.
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%
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.
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%.
z SDSS c6020 2000.00 9400.00 Nicholas U. Mayall 4-meter Telescope Mosaic z SDSS c6020 z SDSS c6020 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.
z SDSS k1020 *** Retired! 2000.00 9400.00 Nicholas U. Mayall 4-meter Telescope Mosaic z SDSS k1020 *** Retired! z SDSS k1020 *** Retired! NOTE: This filter was damaged in June 2011 and is retired. The CTIO SDSS z' filter (c6020) can be requested as a replacement, but it's availability will depend on demand at CTIO. 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.
zd DECam k1038 *** New! 1467.00 9280.00 Nicholas U. Mayall 4-meter Telescope Mosaic zd DECam k1038 *** New! zd DECam k1038 *** 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.

 

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