![]() | Synphot Data User's Guide | |||||
|
1.1 Current Instruments
This section describes the keywords available for the science instruments installed on HST as of January, 2007: the Advanced Camera for Surveys (ACS), the Fine Guidance Sensor (FGS), the Near Infrared Camera and Multi-Object Spectrograph (NICMOS), the Space Telescope Imaging Spectrograph (STIS), and the Wide Field Planetary Camera 2 (WFPC2).
1.1.1 ACS
The ACS keywords consist of a list of detectors, filters, and extraction apertures. The coronagraphic mode may be used only with the HRC detector.
Table 1.1: ACS Keywords
1.1.2 FGS
The FGS instrument keywords consist of a list of filters plus a coordinate axis. Some of the filter names are aliases for other filters. "astroclear" is an alias for "F605W", "clear" is an alias for "F583W", "red" is an alias for "F650W", and "yellow" is an alias for "F550W". One example of an FGS observation mode string would be "
FGS,F583W,Y
".Table 1.2: FGS Keywords
1.1.3 NICMOS
The NICMOS keywords consist of a list of filters, grisms, polarizers, and detectors. Both the filter name and camera number are required in the observation mode. (The detector keyword
tacq
is another way to specify detector 2.)The
dn
keyword is used to divide throughputs by the analog-to-digital converter (ADC) gain ratio, which transforms results from units of electrons to data numbers (DNs).For thermal calculations, all component keywords except the detector may be parameterized for temperature. For more information, see Section 2.5, "Temperature specification (NICMOS, WFC3)" .
Table 1.3: NICMOS Keywords
1.1.4 STIS
The available keywords for STIS include filters, apertures, gratings, central wavelengths, and ADC gains. Each grating or imaging mirror can be used with only one of the three STIS detectors (CCD, NUVMAMA, or FUVMAMA); specifying the grating automatically determines the detector. If no central wavelength is specified, results will be calculated for the entire bandpass of the grating. The ADC gain keywords only apply to the STIS CCD modes and are used to convert results from units of electrons to DNs.
In addition to the aperture names as given in Table 1.4, synphot will recognize aperture names as given in the format used for phase 2 proposals. For example, the aperture name "52X0.05" is equivalent to the aperture "s52x005" listed in the table.
The
mjd
keyword is used to specify the Modified Julian Date which is used to account for time-dependent sensitivity of the FUV and NUV MAMAs. For more details, see Section 2.3, "Modified Julian Date (STIS)" .For important additional details about specifying STIS obsmodes, see Section 3.2, "Specifying STIS observation modes" .
As of January, 2007, STIS is in safe mode due to the failure of the Side 2 power supply in August 2004 (Side 1 had failed in 2001). However, replacement of the Side 2 electronics of STIS is planned during the upcoming HST Servicing Mission 4. If this is successful, STIS will be back in operation.
Table 1.4: STIS Keywords
1.1.5 WFPC2
The WFPC2 keywords consist of a list of detectors, filters, and miscellaneous keywords. The miscellaneous keywords include the ADC gain keywords
a2d7
anda2d15
, which convert results from units of electrons to data numbers (DNs);cal
, which accounts for the flat-field response;lrf#
, which is used for the linear ramp filters; andcont#
, which accounts for changes in throughput between decontamination events (see Chapter 2:Parameterized Keywords for more details on the latter two).The WFPC2 has twelve filter wheels, each of which has five positions, including a clear position. Detector 1 is the PC chip; detectors 2 through 4 are the Wide Field chips. If a detector is not specified, the default is #4. A typical WFPC2 observation mode string would be "
WFPC2,F450W,2
".Table 1.5: WFPC2 Keywords
Space Telescope Science Institute http://www.stsci.edu Voice: (410) 338-1082 help@stsci.edu |
![]() |
![]() |
![]() |
![]() |
![]() |