                          Format description of blokq.dat
 
 
                                Brent Archinal
 
 
                                2000.07.25
 
 
                                Abstract
 
   This document describe format of the file for keeping a priori information
about stations and sources used by various progrms of Mark-4 VLBI Analysis
Software CALC/SOLVE.
 
 
Questions and comments about this guide should be sent to:
 
Leonid Petrov ( pet@leo.gsfc.nasa.gov )
 
 
                                Table of contents:
 
 
1 ................ Overview
 
 
2 ................ Header section
 
 
3 ................ Comments section
 
 
4 ................ Station catalog section
 
 
5 ................ Ocean Loading Catalog section
 
 
6 ................ Source Catalog section
 
 
________________________________________________________________________________
 
        1 Overview
        ==========
 
Records beginning with "$$" in the first two columns are considered
comments and are ignored.
 
There are five major sections in the blokq.dat file:
 
     I- Header
    II- Comments
   III- Station Catalog
    IV- Ocean Loading Catalog
     V- Source Catalog
 
        2 Header section
        ================
 
This section contains four lines (maximum 80 characters per line).
The two lines of data (line 2 & 4) are considered history entries.
 
               ---------
Line 1-  comment line to be given as follows:
$$ FOLLOWING LINE IS SKELETON FILE DESCRIPTION
 
               ---------
Line 2-  file description line, an example follows:
SKELETON 93SEP22: Updated SC-VLBA position  -DG-
 
               ---------
Line 3-  comment line to be given as follows:
$$ FOLLOWING LINE IS VERSION HISTORY ENTRY
 
               ---------
Line 4-  version history entry line, an example follows:
SKELETON 93SEP22: Updated SC-VLBA position  -DG-
 
 
 
        3 Comments section
        ==================
 
All lines in this section are comment lines about changes made to
this file periodically, each line preceded by "$$" in the first
two columns (maximum 80 characters per line).
 
                    ---------
A "header" comment at the beginning of this section should be as
follows:
 
$$ Add comments on changes below - date on last line
added!!!!!!!!!!!!
 
                    ---------
The ending comment line for this section should be as follows:
 
$$//  This line needed for UNIX version of skeleton program in
order
$$     to properly skip over math constants. 90DEC07 -DG-
$$---------------------------------------------------------------
---
 
 
 
        4 Station catalog section
        =========================
 
The station coordinate and antenna data is given as follows:
 
One line per station required (maximum of 80 characters used).
 
  Description        Columns   Read      Notes
                               Format
 
  Station name        5-12     A8        E.g. "CHLBOLTN".
 
  X-coordinate       14-28     D15.3     E.g. " +4008310.312D0".
                                         Units: meters.
 
  Y-coordinate       30-44     D15.3     E.g. "  -100650.866D0".
                                         Units: meters.
 
  Z-coordinate       46-60     D15.3     E.g. " +4943794.642D0".
                                         Units: meters.
 
  Axis type          62        I1        "1"- HADEC, "2"- X/Y-FIXED
                                         AXIS N-S, "3"- AZEL,
                                         "4"- X/Y-FIXED AXIS E-W,
                                         "5"- RICHMOND--(HADEC at
                                          MD latitude moved to
                                          Florida), e.g. "1".
 
  Axis offset        64-70     F7.4      E.g. " 6.7056".
                                         Units: meters.
 
  Zenith atmosphere  71-75     F5.1      E.g. "  7.5".
    delay                                Units: nanoseconds.
 
  Default tectonic   77-80     A4        E.g. "NOAM".
    plate name
 
                     ---------
The ending lines for this section should be as follows:
 
//
$$
$$---------------------------------------------------------------
 
 
 
        5 Ocean Loading Catalog section
        ===============================
 
For each station, one line for station name (maximum of 10
characters used, with the first two characters being blanks) and
six lines for data required (maximum of 78 characters used).
 
                    ---------
  Description         Columns   Read      Notes
                              Format
Station name line:
  Station name        3-10      A8        E.g. "CHLBOLTN".
 
First data line:
  Vertical tidal      2-78      11F7.5    These should be in the
    amplitudes                            order of M2, S2, N2, K2,
                                          K1, O1, P1, Q1, MF, MM,
                                          and SSA.  E.g. " .00199".
                                          Units: meters.
 
Second data line:
  East-west tidal     2-78      11F7.5    E.g. " .00637".
    amplitudes                            Units: meters.
 
Third data line:
  North-sourth tidal  2-78      11F7.5    E.g. " .00091".
    amplitudes                            Units: meters.
 
Fourth data line:
  Vertical tidal      2-78      11F7.1    Same order as amplitudes.
    phases                                E.g. "  322.2".
                                          Units: degrees.
 
Fifth data line:
  East-west tidal     2-78      11F7.1    E.g. "  135.2".
    phases                                Units: degrees.
 
Sixth data line:
  North-south tidal   2-78      11F7.1    E.g. "   -6.2".
    amplitudes                            Units: degrees.
 
                            ---------
The ending lines for this section should be as follows:
 
//
$$
$$----------------------------------------------------------
 
 
 
        6 Source Catalog section
        ========================
 
One line per source required (maximum of 77 characters used).
 
                    ---------
  Description         Columns   Read      Notes
                              Format
 
 
  Source name          5-12     A8        E.g. "0003+380".
 
  RA - hours          15-16     I2        Right ascension of star,
                                          e.g. "23".  Units: hours.
 
  RA - minutes        18-19     I2        Right ascension of star,
                                          e.g. "42".
                                          Units: minutes.
 
  RA - seconds        21-29     F9.6      Right ascension of star,
                                          e.g. "16.679183".
                                          Units: seconds.
 
  DEC - degrees       35-37     I3        Declination of star, e.g.
                                          "-26".  Units: degrees.
 
  DEC - minutes       39-40     I2        Declination of star, e.g.
                                          "10".  Units: arcminutes.
 
  DEC - seconds       42-50     F9.6      Declination of star, e.g.
                                          "59.321119".
                                          Units: arcseconds.
 
  Source reference    58-77     A20       Source reference.
 
 
                    ---------
 
There is a section of comments following the source catalog with
a  maximum of 80 characters used per line.  These comments expand
on the meaning of the "source reference" information in the source
catalog.  The purpose of the comments is to explain any addition
or update on a source position.  For sources not yet observed,
these references should include a reference to the publication or
personal communication that the information about the radio source
came from.  For sources that have been observed (and in particular
a new position determined), the experiment name and its associated
database keyname and stations participating should be listed.  It
is also useful to indicate the affected radio source or sources in
these comments - this is important since later updates may change
the source reference for a particular source.
 
                    ---------
 
The last line in the file should be as follows:
 
//
 
 
