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 |
|---|---|---|---|---|---|---|---|
| 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 June 5, 2021, 8:00 pm