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ecdinfo xray.xdataio.eincdrom



ecdinfo -- display information about a specific Einstein dataset.


ecdinfo specifier inst datatype


ecdinfo allows the user to display information about data from any Einstein dataset. For most datasets, this information includes the field center, the sequence title, and the livetime of the sequence. The information is displayed to the screen and to the hidden parameters.

This task prompts the user for only the parameters which are needed. For instance, if the user uses "H1734S03.XPA" for the specifier, then the instrument (hri) and datatype (event list) are already known.


specifier = "" prompt="FITS filename OR sequence number"

This specifies the requested data. It can be in the form of a FITS filename (i.e. "s0512s42.f3d" or "i0423n15.upa"), or it can be a sequence number (i.e. "9004" or "H1043").

The possible FITS extensions are .xi* (for IPC or HRI image files), .xp* (for IPC or HRI event files), .f3d (for IPC slew data), and .up* (for IPC unscreened data).

inst = "" prompt="Einstein instrument (ipc|hri)"

The instrument (ipc or hri) to get information for. The user will not be prompted for this parameter if the instrument is contained in the specifier.

datatype = "" prompt="Datatype (event|image|slew|unscreened)"

The type of data (event, image, slew, or unscreened) to get information for. Again, the user will not be prompted for this parameter if the data type can be deduced from the specifier.

Note that there is no slew or unscreened data available for HRI.

(is_valid = ) [boolean] [OUTPUT PARAMETER]

This parameter is set to "yes" if the requested data exists.

(seq = ) [string] [OUTPUT PARAMETER]

The sequence associated with the requested data, such as "i9004" or "h1043". This parameter is set to "none" for IPC slew data.

(fits_root = ) [string] [OUTPUT PARAMETER]

The root of the FITS file name for this sequence, such as "i0423n15" or "s0449n84".

(fits_ext = ) [char] [OUTPUT PARAMETER]

The extension letter of the FITS file name, such as "a", "b", "c", etc. For instance, IPC sequence 6839 has the extension "b" for its FITS files. This parameter is set to " " for IPC slew data, since all slew data have the identical extension.

(ra = ) [float] [OUTPUT PARAMETER]

The RA associated with this data set, in degrees.

(dec = ) [char] [OUTPUT PARAMETER]

The DEC associated with this data set, in degrees.

(hour = ) [string] [OUTPUT PARAMETER]

The hour associated with the dataset, e.g., "03h" or "21h". This value should correspond to the RA of the sequence.

(dir = ) [string] [OUTPUT PARAMETER]

The directory which should contain the CDROM holding the data for this sequence. See the eincdpar parameter file for a complete list of CDROM directories.

The main data on each CDROM is stored in the subdirectory data/##h, where ##h is the hour of the data. For example, the IPC event sequence i8102 might have its CDROM in the directory dir="ipcevt4$". If so, its main data is in the directory "ipcevt4$data/22h/".

(evt_off = ) [float] [OUTPUT PARAMETER]

The number of seconds which should be added to every photon arrival time and TGR records in the event file. This is only non-zero for HRI event data. The values come from a table HRI.timing.Erratum available by anonymous ftp at sao-ftp:

"All absolute event times on the HRI Event List CD-ROMs (Jan 1992) are slightly incorrect. Relative times within a sequence are not affected. The following table gives the correct value of the header card XS-TBASE (time of sequence start in seconds since 1978 Jan 0.0 UTC) and the number of seconds, DT, to be added to all event and TGR times in the FITS files (this number is a constant for a given sequence)."

(livetime = ) [float] [OUTPUT PARAMETER]

The livetime associated with the data. See the section below on HRI livetime.

This parameter is zero for IPC slew data since there is no livetime information.

(title = ) [string] [OUTPUT PARAMETER]

The title of the sequence.

(eincdpar = "") [pset]

The name of the file containing the eincdrom package wide parameters. If the name is empty (""), then the parameters will be obtained from the eincdpar task.

(display = 1) [int]

The display level. A setting of 0 should output no display, while settings above 3 are only useful for debugging.


1. Use ecdinfo to retrieve information on the event file for IPC sequence 8102 (xdata$snr.qp).

ei> ecdinfo
FITS filename OR sequence number: i8102
Datatype (event|image|slew|unscreened): event

FITS root: i2258n58, extension: a, sequence 8102.


Ra=22:58:55.7, Dec=58:36:47.6, livetime: 4255.77 seconds.

This sequence should be on the CDROM in the directory ipcevt4$.
ei> lpar ecdinfo
    specifier = "i8102"         FITS filename OR sequence number
         inst = "ipc"           Einstein instrument
     datatype = "event"         Datatype
    (is_valid = yes)            Was the requested specifier & inst & datatype va
         (seq = "i8102")        Sequence number
   (fits_root = "i2258n58")     FITS root
    (fits_ext = "a")            FITS extension (i.e. 'a', 'b', etc.)
          (ra = 344.7319)       RA of sequence (in degrees)
         (dec = 58.61323)       DEC of sequence (in degrees)
        (hour = "22h")          Sequence hour
         (dir = "ipcevt4$")     Directory containing the CD with sequence data
     (evt_off = 0.)             Event time offset correction
    (livetime = 4255.7734375)   Livetime of sequence
       (title = "I08102 CTB 109 (POSSIBLE UNKNOWN SNR W/COMPACT SOURCE)") Sequen
    (eincdpar = "")             Eincdrom package parameters
     (display = 1)              display level
        (mode = "ql")           

2. Use ecdinfo to retrieve information on the unscreened version of IPC sequence 8102.

ei> ecdinfo
FITS filename OR sequence number: i2258n58.upa

FITS root: i2258n58, extension: a, sequence 8102.


Ra=22:58:55.7, Dec=58:36:47.5, livetime: 7503.87 seconds.

This sequence should be on the CDROM in the directory ipcu18$.


The document deadtime.asc (located on the HRI image and HRIEVT CDROMs) gives deadtime corrections for most of the HRI sequences. However, there are 105 HRI sequences for which there is no dead-time correction information available. For these sequences, the parameter "livetime" contains the on-time instead. The sequences are as follows:

2	3	7	12	15	401	474	*631	*632
*633	*647	651	*708	*710	714	717	718	*719
783	*818	*819	*820	821	*822	823	*824	*826
*935	*937	940	*941	*943	*945	973	975	1031
1036	1061	1806	2111	*2843	*2844	*2845	2906	3047
*3364	*3502	3503	*4276	4364	4486	4859	4860	4862
4873	5249	5747	5750	5755	5917	6299	6544	6546
*6621	*6622	*6623	*6624	*6626	*6627	*6628	*6629	*6630
*6631	*6632	*6720	*6761	*6762	*6763	*6764	*6765	*6766
*6767	*6768	*6769	*6770	6814	7691	7717	7926	7927
7981	*8338	*8342	8476	*8934	9262	*9537	*9538	10276
10316	*10367	*10649	10757	10760	10777

(The starred sequences are OGS sequences.)

There are also five sequences whose on-time differed from what was expected in the deadtime.asc file. These sequences are as follows:

     seq      on-time in HRI FITS   deadtime.asc    DTC

     282	  75568.69	      75609.6      1.035
     349	   2804.16	      12831.4      1.019
     981	    149.44	       3280.3      1.017
    6335	   2404.80	      28939.5      1.026
   10139	  25569.58	      24907.2      1.044

For these five sequences, we calculated the livetime by multiplying the dead-time correction from the deadtime.asc file by the on-time found in the HRI FITS file.


There are a few FITS files with RA and DEC values which do not match the FITS name or hour. For example, see IPC event sequence 8760.


This task typically takes under 5 seconds to run on a SPARCstation.


See ecd2pros to convert FITS files on the Einstein CDROMs into PROS format.

See explain_eincdrom for more information on the data on the CDROMs.

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