This file is for quick reference. Please consult the LMI Users Manual for more detailed information.
LMI Filters:
Currently available filters for LMI are given in the table below. This table also includes the focus offset (wrt OPEN) that is applied when each filter is selected and the approximate length of a dome flat (Exp Time) resulting in counts of ~20,000 (selecting the time will link to an image of a flat of that length).
Sample flats for the various filters taken over time can be found on the LMI Filter Characterization page.
NOTE: Some of these values are incorrect. Please refer to the LMI GUI offsets for the time being until the focus offsets can be checked.
Filter Names for use in Pattern Files:
When using filters in the automated pattern files, the filter name has to match the LOUI display string for the filter. Since that may not always be what you think it is, the table includes both the string for use in pattern files (Pattern String) and the corresponding string that will be inserted into image FITS headers (FITS Header Value).
| Filter | Pattern String | FITS Header Value | Focus Offset (µm) | Approximate Exp Time (seconds) | Filter Central Wavelength (A) | Filter Width (A) |
|---|---|---|---|---|---|---|
| Miscellaneous Filters | ||||||
| OPEN | OPEN | OPEN | 0 | |||
| DARK | DARK | DARK | N/A | |||
| 4 Hole Mask | 4Hole | 4HOLEMASK | ||||
| Johnson-Cousins Filters | ||||||
| U | U | U | +140 | 178 | ||
| B | B | B | +105 | 9 | ||
| V | V | V | +105 | 5 | ||
| R | R | R | +140 | 3.5 | ||
| I | I | I | +140 | 3.3 | ||
| V+R | VR | VR | +185 | 6091.7 | 1763.9 | |
| Sloan (SDSS) Filters | ||||||
| SDSS u' | SL-u | SDSS-U | +180 | 313 | ||
| SDSS g' | SL-g | SDSS-G | +180 | 4.5 | ||
| SDSS r' | SL-r | SDSS-R | +180 | 3.5 | ||
| SDSS i' | SL-i | SDSS-I | +180 | 4.25 | ||
| SDSS z' | SL-z | SDSS-Z | +180 | 3.25 | ||
| Narrow Band Filters | ||||||
| Yish | Yish | YISH | +105 | 26 | ||
[Oiii] | OIII | OIII | +205 | 180 | 5001.7 | 25.5 |
| Hα-On | Ha-on | HALPHAON | +155 | 115 | 6564.9 | 30.1 |
| Hα-Off | Ha-off | HALPHAOFF | +155 | 37 | 6459.1 | 114.6 |
| Wolf-Rayet Filters | ||||||
| WC | WC | WR-WC | +165 | 115 | 4660.4 | 49.5 |
| WN | WN | WR-WN | +160 | 4690.9 | 49.6 | |
| CT | CT | WR-CT | +170 | 4756.1 | 54.6 | |
| Comet Filters | ||||||
| Ultraviolet Continuum | UC | UC | +175 | 500** | 3449 | 79 |
| Blue Continuum | BC | BC | +175 | 130 | 4453 | 61 |
| Green Continuum | GC | GC | +175 | 119 | 5259 | 56 |
| Red Continuum | RC | RC | +175 | 70 | 7133 | 58 |
| C2 | C2 | C2 | +175 | 46 | 5135 | 119 |
| C3 | C3 | C3 | +175 | 4063 | 58 | |
| CN | CN | CN | +175 | 480 | 3869 | 56 |
| CO+ | CO+ | CO+ | +175 | 160 | 4266 | 64 |
| H2O+ | H2O+ | H2O+ | +175 | 7028 | 164 | |
| OH | OH | OH | +175 | 480** | 3097 | 58 |
| NH | NH | NH | +175 | 3361 | 54 | |
| Assorted Other Filters (inquire if you want to use, as they may not be readily available) | ||||||
| W032 | W032 | W032 | +176 | 5300 | ||
| 5027 | 5027 | 5027 | +130 | 5027 | ||
| K1593 | K1593 | K1593 | +194 | 5010 | ||
** OH & UC counts were at about the bias level for this exposure time & thus not a great candidate for dome flats.