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Realtime Public TOO Archive

The RXTE Team is committed to making archival data available promptly and conveniently.


Why is there a separate realtime TOO archive?

All TOO observations not initiated by accepted NRA proposals enter the public domain instantly. In addition, some accepted NRA TOO proposals may specify that the data are made immediately public, and RXTE calibration observations (blank-sky background, certain calibration sources) also have no proprietary period. Fully processed data from these observations are available in the RXTE Archive, 8 days after the observation occurs.

Mindful of the immediate interest in these observations, the RXTE team makes the corresponding realtime data available to the community daily, via the Realtime Public TOO Archive. For more information on the difference between realtime data and fully processed production data, see the RXTE GOF data analysis recipe Working with Realtime Data.

How are the data organized in the Archive?

The realtime TOO data occupy the xte/data/realtime directory on the anonymous FTP server at legacy.gsfc.nasa.gov. Directories at the next lowest level are named after the individual ObsIds, e.g. 10401-01-38-00, and contain a single tar file, e.g. 10401-01-38-00.tar.

When untarred, the file yields a directory named after the ObsId which contains:

  1. Index files for the various Spacecraft Subsystems. These have names like FIAC_473e891-47430c1.

  2. FMI (FITS Master Index) file. This provides a description of the contents of the directory. It is used by XDF - the XTE Data Finder - to identify the underlying data files.

  3. Spacecraft Subsystem directories. All are present, but only the essential subsystems, listed below, actually contain files:

    acs - Attitude Control System (only AppIds 14, 15)
    clock - Time delta correction data from Mission Operations Center
    fds - Flight Data System (only AppId 1)

    hexte - HEXTE science and housekeeping data (all AppIds when available, except
    burst mode, i.e. 80, 82, 83, 84, 85, 86, 88, 89, 251, 252, 253, 254)
    orbit - Orbit ephemeris from the Flight Dynamics Facility
    pca - PCA science and housekeeping data (all AppIds when available, i.e. 55, 59, 63,
    70, 74, 79, 90-94)
    stdprod - Standard products generated by the XSDC (only the data files with raw
    data, i.e. 237, 238, 239, 240, 241, 242, 243)

    Though they represent the lowest rung in the directory hierarchy, the Subsystem directories do not necessarily contain files of one type. In most cases, a further division is made based on Application, the term used for a distinct source of telemetry. In the case of the PCA, the six Event Analyzers are considered applications. Note that the ASM is not included.

    Files in the acs, fds, hexte, pca and stdprod directories require gunzip to be run before use.

Which targets are present?

The contents of the Realtime Public TOO Archive cannot be browsed with Browse, unlike the "full" Archive. However, the SOF has provided a convenient list of TOO targets which contains links to download the publicly available data. Please note that the NRA TOOs which also appear in the list become publicly available a year after observation.

How are realtime data different from production data?

As the name implies, realtime data are telemetred when the spacecraft is in contact with the ground station. Production data, on the other hand, comprise daily batches of realtime data put together by the data capture facility. These data have been time-sorted and with duplicate telemetry removed. Consequently, users should be aware of the following caveats concerning data in the Realtime Public TOO Archive:

  1. Start and stop times of these observations are estimated to the best of our (planning) knowledge, but may not be entirely accurate.

  2. Data gaps may occur at random intervals because of breaks in the realtime telemetry.

  3. We have processed only a limited number of AppIds, though a digest of some others is available in the stdprod directory (see above).

  4. Orbit ephemerides are not yet available for these observations; one will have to wait for the definitive products.

  5. Complete filter files can be generated from realtime data, but only with a few additional steps, as described in the recipe Working with Realtime Data.

How to proceed with data reduction and analysis

  1. Read the Getting Started Guide.

  2. Read the materials on the Data Analysis & Processing page, especially the recipe Working with Realtime Data in the RXTE Cook Book.

  3. Consult RXTE Frequently Asked Questions.

If you have a question about RXTE, please send email to one of our help desks.

This page is maintained by the RXTE GOF and was last modified on Wednesday, 17-Mar-2004 15:04:46 EST.