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 |
|---|---|---|---|---|---|---|---|
| M Washington k1007 | 1140.00 | 5100.00 | Nicholas U. Mayall 4-meter Telescope | Mosaic | M Washington k1007 | M Washington k1007 | 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 plot at the bottom of the page. |
| 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. | ||
| M Washington c6007 | 1020.00 | 5020.00 | Nicholas U. Mayall 4-meter Telescope | Mosaic | M Washington c6007 | M Washington c6007 | 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 | Nicholas U. Mayall 4-meter Telescope | Mosaic | V Harris k1003 | V Harris k1003 | |||
| 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. |
| 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. |
| 607 BATC k1058 ** | Nicholas U. Mayall 4-meter Telescope | Mosaic | 607 BATC k1058 ** | 607 BATC k1058 ** | |||
| 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. |
| 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. | ||
| ha16 H-alpha+16nm k1013 | 81.10 | 6730.72 | Nicholas U. Mayall 4-meter Telescope | Mosaic | ha16 H-alpha+16nm k1013 | ha16 H-alpha+16nm k1013 | 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. |
| 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. |
| 420 BATC k1053 ** | Nicholas U. Mayall 4-meter Telescope | Mosaic | 420 BATC k1053 ** | 420 BATC k1053 ** | |||
| D51 DDO 51 c6008 | 154.00 | 5130.00 | Nicholas U. Mayall 4-meter Telescope | Mosaic | D51 DDO 51 c6008 | D51 DDO 51 c6008 | 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 | Nicholas U. Mayall 4-meter Telescope | Mosaic | V Harris k1003 | ||||
| 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. |
| 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. | ||
| 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. |
| D51 DDO 51 k1008 | 162.90 | 5145.20 | Nicholas U. Mayall 4-meter Telescope | Mosaic | D51 DDO 51 k1008 | D51 DDO 51 k1008 | 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. |
| 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_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. | ||
| ha H-alpha c6009 | 80.00 | 6563.00 | Nicholas U. Mayall 4-meter Telescope | Mosaic | ha H-alpha c6009 | ha H-alpha c6009 | 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 Harris k1004 | 1511.30 | 6513.54 | Nicholas U. Mayall 4-meter Telescope | Mosaic | R Harris k1004 | R Harris k1004 | 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% | ||
| Gn Steidel k1042 | 762.13 | 4819.66 | Nicholas U. Mayall 4-meter Telescope | Mosaic | Gn Steidel k1042 | Gn Steidel k1042 | 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 ** | |||
| Bj Tyson c6024 *** Not Available | 1650.00 | 4350.00 | Nicholas U. Mayall 4-meter Telescope | Mosaic | Bj Tyson c6024 *** Not Available | Bj Tyson c6024 *** Not Available | 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. |
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