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ROSATLOG: Help

ROSATLOG - ROSAT Observation Log


Overview

The ROSATLOG database has been created for the purpose of providing a complete, accurate, and easily accessible record of ROSAT observations.

ROSATLOG is made by cross-correlating ROSAT observation records with the short-term timeline and contains information about all pointings executed by the satellite during the performance verification (PV) and AO phases. For each observation, details are given concerning target name and coordinates, pointing start and stop times, PI name and country, ROSAT Observation Request sequence number, and more.

ROSATLOG is based on the short-term timelines and observation records generated at the German ROSAT Science Data Center at the Max Planck Institute for Extraterrestrial Physics (MPE) and sent to the ROSAT Guest Observer Facility at Goddard Space Flight Center (GSFC).


Description

The ROSATLOG database has been made as accurate a record of ROSAT pointings as is possible with the available information. The primary source of information for the database is ASCII files dumped from a database at MPE. These ASCII files contain information originally extracted from the attitude protocol files, which are daily-generated files containing coordinate and time values for each day's ROSAT pointing. Errors in the information extracted from the attitude protocol files are weeded out and corrected in the database at MPE as necessary, and the final versions of the ASCII files are output and sent to the ROSAT GOF at GSFC, to be used as the basis for the ROSATLOG database.

Each observation listed in the MPE ASCII files has a ROSAT Observation Request (ROR) sequence number associated with it. Using this sequence number, the observation is matched with the corresponding entry in the ROSAT short-term timeline. (The short-term timeline is also generated by MPE, approximately one week in advance of observations. It is available online within the HEASARC database system, as a database called ROSSTL.) Information such as PI name, country, target name and number, primary instrument, solar angle, time constraints, etc., is then extracted from the timeline and put into the ROSATLOG database. (NOTE: Typing the BROWSE command `lparm` will display all the ROSATLOG parameter names and one-line descriptions to the screen. Those parameters with an asterisk at the beginning of their descriptions are parameters whose values come from the ROSAT short-term timeline; parameters without asterisks contain values extracted from the MPE ASCII files.)

Certain ROSATLOG entries may have parameter fields which contain `??`, `UNKNOWN`, or are blank. In these cases, either the ROR was not found in the short-term timeline or the ROR was found but the completed observation could not be matched with one of the planned observations listed in the short-term timeline.

Despite efforts to make ROSATLOG a complete and accurate record of ROSAT pointings, some errors may still appear; thus ROSATLOG should be used only as a basic guide to what pointings have been executed. ROSATLOG shows in which direction ROSAT pointed and at what time. HOWEVER, it does NOT reflect problems which may have occurred during the pointing and which can result in the total exposure time being much less than the duration of the pointing.


Parameters

Julian_Date
Julian Date from MPE data file

Rday
The ROSAT day number at the start of the pointing (June 2, 1990 has RDAY = 1). ROSAT day numbers between 1 and 60 are from the performance verification (PV) phase, while day numbers greater than ~256 are from the AO1 phase.

Date_Observed
Date observed in YYMMDD format

Requested_Time
Time observed in seconds

Sclk_Start
The spacecraft clock seconds of day at the ACTUAL start of the pointing.

Sclk_End
The spacecraft clock seconds of day at the ACTUAL end of the pointing.

Duration
The duration of the pointing, in seconds.

PLEASE NOTE: The `duration` shown here indicates only the length of time that the telescope pointed in a certain direction; it is NOT a total observation time. Operational or other problems may have occurred during the pointing which would cause the total observation time to be less than the `duration` given here.

Expected_RA
Predicted RA (degrees,j2000)

Expected_Dec
Predicted DEC (degrees,j2000)

RA
The PREDICTED right ascension of the pointing.

Dec
The PREDICTED declination of the pointing.

LII
Galactic Longitude

BII
Galactic Latitude

Xoff
X pointing offset.

Yoff
Y pointing offset.

ROR
The ROSAT observation request sequence number.

Instrument
The prime instrument for this observation.

RA_B1950
Avg measured RA (degrees,1950)

Dec_B1950
Avg measured DEC (degrees,1950)

MJD_Time
Actual start in MJD

MJD_End_Time
Actual end in MJD


Contact Person

Questions regarding the ROSATLOG database table can be addressed to the HEASARC User Hotline.
If you have any problems, please consult the help page or mail ledas-help@star.le.ac.uk
 
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