File names and suffixes used by GHRS (Z)

ST-ECF fileid STSDAS suffix File content Example
Raw data files
zxxxxxxxx.d0f .d0h Raw science data Z0D80106T.D0F
zxxxxxxxx.q0f .q0h Data quality for raw science image Z0D80106T.Q0F
zxxxxxxxx.d1f .d1h Return-to-Brightest & SSA ACQ/PEAKUP Z0D80106T.D1F
zxxxxxxxx.q1f .q1h Data quality for RTB & SSA ACQ/PEAKUP Z0D80106T.Q1F
zxxxxxxxx.x0f .x0h Extracted engineering data Z0D80106T.X0F
zxxxxxxxx.xqf .xqh Data quality for extracted engineering data Z0D80106T.XQF
zxxxxxxxx.shf .shh Standard Header Packet Z0D80106T.SHF
zxxxxxxxx.ulf .ulh Unique Data Log Z0D80106T.ULF
zxxxxxxxx.trl .trl Trailer file Z0D80106T.TRL
Calibrated data files
zxxxxxxxx.c0f .c0h Calibrated wavelength solution Z0D80106T.C0F
zxxxxxxxx.c1f .c1h Calibrated science data (fluxes) Z0D80106T.C1F
zxxxxxxxx.c2f .c2h Propagated statistical error Z0D80106T.C2F
zxxxxxxxx.c3f .c3h Calibrated special diodes Z0D80106T.C3F
zxxxxxxxx.c4f .c4h Special diodes data quality Z0D80106T.C4F
zxxxxxxxx.c5f .c5h Background Z0D80106T.C5F
zxxxxxxxx.cqf .cqh Calibrated science data quality Z0D80106T.CQF
zxxxxxxxx.jif .jit, .jih Jitter files (post- and pre-COSTAR) special
zxxxxxxxx.pdq .pdq or .ocx PODPS data quality files special

Uncalibrated Data

Science Data (.d0h and .q0h)

The science data (.d0h image) contains the single-precision floating point values representing the number of detected counts accumulated for each diode, just as it comes from the spacecraft. Depending on the stepping pattern (STEPPATT) used for the observation, there may be only one, or up to six groups of science data per exposure. The default STEPPATTs are listed in Table 35.3 and the implications are discussed more in "file Sizes" on page 35-5. The science data are read out from the 500 science diodes (see the GHRS Instrument Handbook). The data quality image (.q0h) associated with the science data records whether there is "fill" data due to technical problems with the observation or due to problems in transmitting the data from the telescope. The .q0h file contains where the data are good, and ones for Reed-Solomon errors (related to data transmission) and 16 for fill data.

ACQ/PEAKUP (.d1h and .q1h)

Most acquisitions of point sources since mid-1993 used the return-to-brightest algorithm, in which the aperture (LSA or SSA) was rastered in a 3 x 3 or 5 x 5 pattern, and the pointing with the most counts was returned to for peakup and observation. The return-to-brightest (RTB) target acquisition record is in the .d1h image and also in the trailer file (.trl). This image contains the total counts at each dwell point in the spiral search performed by the RTB acquisition algorithm. SSA ACQ/PEAKUPs use the same algorithm as RTB target acquisitions. Therefore they will also have a .d1h file whose header file contains information on which dwell point (MAPFND) contained the largest flux (FLUXFND). The data quality image (.q1h) associated with the RTB data records whether there is fill data due to technical problems with the observation or due to problems in transmitting the data from the telescope.

Extracted Engineering Data (.x0h)

For ACCUM and RAPID mode observations, the extracted engineering data GHRS / 35 image (.x0h) consists of 24 pixels which contain the values of the twelve special diodes (i.e., focus, background monitor, and radiation monitor diodes; see the GHRS Instrument Handbook) in the detector and twelve pixels of engineering trailer and flight software data relevant to each pattern execution (see Table 35.2). The data quality file (.xqh) records whether any of the data represent fill due to technical problems with the observation or telescope during the observation. These data are sometimes used for determining the background count rate.

Standard Header Packet (.shh)

The standard header packet (SHP, image suffix .shh) contains the telemetry values from the engineering data and some GHRS-unique data. The engineering data includes temperatures, currents, and voltages at various points in the instru- ment. The header packet also contains information used in the operation of the spacecraft, such as target name, position, and velocity of the telescope, the right ascension and declination of the target, Sun, and Moon, and other proposal infor- mation used in the observation which was provided in the Phase II part of the pro- posal. There is one group of .shh data per pattern used in the observation. Various items from the SHP are used in various steps of the reduction process.

Unique Data Log (.ulh)

The unique data log (UDL, image suffix .ulh) contains the command values (i.e., the Observation Control Table) used to control the aperture, detector, carrou- sel, Digicon deflections, observing modes, and flux measurements as well as some observation data produced by the flight software. There are two groups of .ulh data per pattern per observation. For images and standard ACCUM mode, a lead- ing and following UDL are readout that bracket the observation.

Trailer file (.trl)

The trailer file (suffix .trl) contains many messages generated by the conver- sion of the data from what is on-board the spacecraft into STSDAS images. These messages include information on missing or filled packets, RTB information for some acquisitions, and the informational messages produced by calhrs as it is used to calibrate the data.

Calibrated Data

Calibrated Wavelength Solution (.c0h)

The calibrated wavelength solution (.c0h) image contains the wavelengths in Angstroms for each corresponding pixel in the .c1h file. The dimensions and number of groups is the same as the .c1h file. This file is produced when ADC_CORR is set to PERFORM.

Calibrated Science Data (.c1h)

The calibrated science data (.c1h) image contains the calibrated science data, and is always produced by calhrs. The number of groups and dimensions of the spectra depends on the stepping pattern used (STEPPATT, see Table 35.3 and "file Sizes" on page 35-5) in the observation and also which calibration steps are performed. The contents can range from being an exact copy of the raw science data (found in the .d0h image) to a fully flux-calibrated spectrum.

Propagated Statistical Error (.c2h)

The propagated statistical error (.c2h) image contains the propagated statisti- cal error associated with the .c1h science data. The number of groups and dimen- sions of this file will be the same as the .c1h image. The units of the error will also be the same as the final units of the science data.

Calibrated Special Diodes (.c3h)

This twelve-pixel image contains the calibration of the special diodes whose raw values correspond to the first twelve pixels in the .x0h file (see Table 35.2).

Special Diode Data Quality (.c4h)

The special diode data quality (.c4h) image contains the data quality flags for the special diodes. See Table 37.5 for data quality flags.

Background (.c5h)

The background (.c5h) image contains the actual subtracted background. The units of the background will be either in counts or count rate, depending on the setting of the EXP_CORR switch. This file is produced when a background cor- rection is performed. You have several options for calculating the background rate.

Calibrated Science Data Quality (.cqh)

The calibrated science data quality (.cqh) image contains the data quality flags associated with each pixel in the calibrated science data image. The flags are num- bers; the higher the value, the worse the data in the corresponding pixel. See A

calibrated data quality flags (Diode Array.c3h or .x0h )

Index Pixel # Description
1 1 Upper left background (corner) diode
2 2 Lower left background (corner) diode
3 3 Left high-energy diode
4 4 Middle focus (disabled) diode
5 5 Upper left focus diode
6 6 Lower left focus diode
507 7 Upper right focus diode
508 8 Lower right focus diode
509 9 Middle focus diode
510 10 Right high-energy diode
511 11 Upper right background (corner) diode
512 12 Lower right background (corner) diode