Level 0 Data#
Overview#
Level 0 data are provided in the FITS file format. For more information on how to read or write FITS file see astropy.fits. This section describes the organization the level 0 FITS files. Level 0 fits files generally include the unconverted data from the raw binary files of ccsds packets. The purpose of these files is to provide the raw data from the raw binary files in a more convinient form for analysis. It also provides metadata information which summary the data in the file.
Level 0 event files#
This file contains the data from all events that triggered the detectors.
They consist of 3 HDUs including the primary HDU.
The primary HDU contains no data and is only used for metadata.
The two other HDUs are named SCI and PKT.
SCI includes the event data while PKT includes the packet data.
Each data packet may include one of more event therefore there is a one to many relationship between them.
In order to understand the relationship between the events and packets, each event provides the associated packet sequence number.
This sequence number can be used to lookup the packet data for that event.
Primary HDU#
No data is provided. Stay tuned for a list of metadata
PKT HDU#
The following columns are provided for each data packet. The bits column provide the number of significant bits and not the bit length of the column itself. The columns in the FITS file are provided in the smallest possible data type.
name |
bits |
|
|---|---|---|
seqcount |
packet sequence number, should be consecutive |
12 |
pkttimes |
the packet time in seconds since EPOCH |
32 |
pktclock |
the packet subsecond time in clocks |
32 |
livetime |
live time |
16 |
inttime |
integration time in real time |
16 |
flags |
flags |
16 |
SCI HDU#
The following columns are provided for each event or photon detected. The bits column provide the number of significant bits and not the bit length of the column itself. The columns in the FITS file are provided in the smallest possible data type.
name |
description |
bits |
|---|---|---|
seqcount |
packet sequence number |
12 |
clocks |
the clock number |
16 |
asic |
the asic number or detector id |
3 |
channel |
the asic channel which is related to the pixel |
5 |
atod |
the uncalibrated energy of the event in ADC counts |
12 |
baseline |
the baseline measurement if exists, otherwise all zeros |
12 |
pkttimes |
the packet time in seconds since EPOCH, also exists in PKT, |
32 |
pktclock |
the packet time in clocks since EPOCH, also exists in PKT |
32 |
Level 0 spectrum files#
Summary spectra are created for 24 pixels at a regular cadence (normally every 10 s) Each spectrum has a total of 512 energy bins.
Level 0 housekeeping files#
These files contain housekeeping data as described in the housekeeping packet. It also includes any register read responses that may exist during that time period.