Bias, Parameter Block, & Orbit Ephemeris Files
| Filename | Description | Content | SDP Pipeline |
|---|---|---|---|
| acis_bias0.fits | ACIS bias maps | BIAS0 | ACIS0 |
| acis_pbk0.fits | ACIS parameter block | PBK | ACIS0 |
| orbit_eph1.fits | orbit ephemeris | ORBITEPHEM1 | EPHEM1 |
ACIS Bias Maps
| Filename | Description | Content | SDP Pipeline |
|---|---|---|---|
| acis_bias0.fits | ACIS bias maps | BIAS0 | ACIS0 |
Description:
When the bad pixel list is created, each bias map is searched for pixels whose bias values are either too low or too high. There is one 1024x1024 pixel bias map image for each ACIS chip that was used for the observation.
There are no creator tools; the bias maps are generated internally.
ACIS Parameter Block
| Filename | Description | Content | SDP Pipeline |
|---|---|---|---|
| acis_pbk0.fits | ACIS parameter block | PBK | ACIS0 |
Description:
The parameter block file is needed in conjunction with the bias maps when creating a new bad pixel list. It is used to determine observational parameters, such as which CCDs are active, the READMODE and DATAMODE, etc.
There are no creator tools; the parameter block solution file is generated internally.
Columns:
| Column Name | Units | Description |
|---|---|---|
| CCD_ID | CCD ID | |
| FEP_ID | Front End Processor ID | |
| VIDRESP | CCD video chain response selection, 0 for 1:1 | |
| EVT_THR[4] | adu | Event thresholds for nodes A-D |
| SPL_THR[4] | adu | Split thresholds for output nodes A-D |
| BCMPSLOT | Slot identifier for bias map compression tab | |
| BIASALG | Bias algorithm is. 1:whole frame; 2:strip | |
| BIASARG0 | Bias arguement 0 | |
| BIASARG1 | Bias arguement 1 | |
| BIASARG2 | Bias arguement 2 | |
| BIASARG3 | Bias arguement 3 | |
| BIASARG4 | Bias arguement 4 | |
| VID_OFF[4] | Video offsets for CCD output nodes A-D |
ACIS Exposure Statistics
| Filename | Description | Content | SDP Pipeline |
|---|---|---|---|
| acis_stat1.fits | Exp. Stats | EXPSTATS | ACIS1 |
Description:
The ACIS exposure statistics file contains one extension that contains various statistics about each good ACIS exposure, and then has one extension for each CCD_ID that contains minimal information about dropped exposures (due to telemetry saturation).
Users will note that since the CCD's are clocked out asynchronously that the same exposure number, EXPNO, will have a different TIME value.
Creator tool: acis_format_events
Columns:
| Column Name | Units | Description |
|---|---|---|
| TIME | s | Time |
| CCD_ID | CCD ID number | |
| EXPTIME | s | Exposure time |
| EXPNO | Exposure Number | |
| EVTSENT | Number of events telemetered | |
| THR_PIX | Number of pixels above threshold | |
| DROP_AMP | Number of events outside energy filter | |
| DROP_POS | Number of events outside window | |
| DROP_GRD | Number of events with bad grades | |
| BERR_SUM | Number of bias parity errors | |
| OVRCLOCK | adu | Mean overclock for each node |
Orbit Ephemeris
| Filename | Description | Content | SDP Pipeline |
|---|---|---|---|
| orbit_eph1.fits | orbit ephemeris | ORBITEPHEM1 | EPHEM1 |
Description:
The definitive orbit ephemeris information for the observation. The coordinates are recorded as Earth-centered Cartesian ICRS coordinates.
There are no creator tools; the orbit ephemeris file is generated internally.
Columns:
| Column Name | Units | Description |
|---|---|---|
| Time | s | Time |
| X | m | X coordinate |
| Y | m | Y coordinate |
| Z | m | Z coordinate |
| Vx | m/s | Velocity in the X direction |
| Vy | m/s | Velocity in the Y direction |
| Vz | m/s | Velocity in the Z direction |