11.5.2 COS Spectral Elements and Central Wavelengths
This article lists the legal COS spectral element/wavelength combinations for the COS/FUV and COS/NUV configurations. |
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Format definitions
Boldface type indicates the name of an APT parameter or a value for a parameter.
Black text indicates an important note.
Magenta text indicates available but unsupported parameters (requires prior approval from STScI).
Red text indicates restricted parameters (for STScI use only).
Brown text indicates text file parameters.
Items in brackets - <value> - are required values.
Items in square brackets - [<value>] - are optional.
The following table specifies the legal COS spectral element/wavelength combinations for the COS/FUV and COS/NUV configurations. For information on the Lifetime Positions used for each central wavelength see
Table 11.5: COS Spectral Elements and Central Wavelengths
Configuration | Spectral Element | Central Wavelengths (Angstroms) |
COS/FUV | G130M | 10551, 10961, 12221, 1291, 1300, 1309, 1318, 1327 |
G140L | 8001, 1105, 1230, 1280 | |
G160M | 15331, 1577, 1589, 1600, 1611, 1623 | |
COS/NUV2 | G185M | 1786, 1817, 1835, 1850, 1864, 1882, 1890, 1900, 1913, 1921, 1941,1953, 1971, 1986, 2010 |
G225M | 2186, 2217, 2233, 2250, 2268, 2283, 2306, 2325, 2339, 2357, 2373, 2390, 2410 | |
G230L | 2635, 2950, 3000, 3360 | |
G285M | 2617, 2637, 2657, 2676, 2695, 2709, 2719, 2739, 2850, 2952, 2979, 2996, 3018, 3035, 3057, 3074, 3094 | |
MIRRORA3 | N/A | |
MIRRORB4 | N/A |
1Target acquisition modes are not allowed with this central wavelength.
2Due to increased COS NUV detector background and mechanism position uncertainties, certain central wavelength settings have proven to be unreliable in the NUV ACQ/PEAKXD target acquisition phase. The central wavelengths settings that appear in bold are the preferred central wavelengths for STRIPE=DEF NUV ACQ/PEAKXD exposure. See the COS Instrument Handbook and Mode = ACQ/PEAKD Config = COS/NUV for more details.
3The MIRRORA spectral element positions a flat mirror in the beam to produce an image of the sky with a field of view slightly larger than the diameter of the aperture. If you intend to produce an image and there are no special bright object concerns, MIRRORA should be used. Restricted for wavecals and forbidden for flats.
4MIRRORB uses the same mirror which has an order-blocking filter in front of it, so that the light is reflected off the front surface of the filter rather than the mirror itself. MIRRORB attenuates the image and is suitable for use with bright objects. Restricted for wavecals and forbidden for flats.
For available but unsupported Configurations at non default lifetime positions
Related Links
11.5.1 COS Internal Calibration Targets
11.5.3 COS Apertures
11.5.4 COS WAVECAL Exposure Parameters
11.5.5 COS Coordinate System