12.15 COS Internal Calibration Targets

The following internal calibration targets are available for the COS. These should not be included in your proposal if the routine calibrations are sufficient for your program. See the COS Instrument Handbook for details.

Table 12.4: Internal Calibration Targets for COS

Target Name	Mode	Description	Aperture and Spectral Element
WAVE1	TIME-TAG	A wavelength calibration exposure for the grating and central wavelength being used for the spectroscopic science observations. The number of iterations must be 1.	Aperture = WCA, Spectral Element = Any element from Table 12.32 except MIRRORA and MIRRORB

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1

Exposures specified with the WAVE internal target will use the same calibration lamp configuration and exposure time as the automatic wave calibrations discussed below (based on the spectral element and central wavelength used).

Unless specifically requested in the Exposure Specification, a TIME-TAG Mode wavelength calibration will be automatically performed for each set of external spectrographic science exposures using the same spectral element, central wavelength, and OSM offset, including each subexposure of an exposure specification with optional parameter FP-POS=ALL. A wavelength calibration exposure will be added prior to the first such science exposure and after each subsequent science exposure if more than 40 minutes of visibility time have elapsed since the previous wavelength calibration exposure. The calibration lamp configuration and exposure time will be based on the grating and central wavelength of the science exposure. For a detailed description of wavelength calibration exposures, see the COS Instrument Handbook.

2

DEF = same as the prior or subsequent spectroscopic science observation (i.e., if no element is specified, then the previously used one is assumed.