PI - star catalogue usage

1. General description of star catalogue

PI star catalogue is based on two tables : STARS and MEASUREMENTS detailed description of these tables can be found here. Table STARS contains all stars observed by PI system
and table MEASUREMENTS contains measurements of this stars on subsequent frames. Each record of table MEASUREMENTS contains link to table STARS ( field star ) and FRAME ( field id_frm).

2. Example databases

Specialy prepared database for testing reasons and recommended to be used is :

   http://grb.fuw.edu.pl/pi/catalog/heplx43/pidb_test/

From command line it can be accessed after logging to heplx43 machine :

    ssh heplx43 -l ogloza
    psql pidb_test -U pidb_guest

Nice example of light curves are : example_lc1, example2



Another example is :

    http://grb.fuw.edu.pl/pi/catalog/20050203_2

There is number of test databases available for pi-users , they can be accessed by WWW interface from here :

    http://grb.fuw.edu.pl/pi0/daq/curves/

There are computers on which database are available listed there. Final database to analyse can be choosen according to description in file, for example :

    http://grb.fuw.edu.pl/pi0/daq/curves/heplx46/conf/conf20041215k2b

In case one wants to make custom analyse of stars in database he must write C/C++ program or script to access data in database. And run it on machine from which database is accessible
( heplx40 or machine were database is running - heplx46 in example above ).
Example of such perl script which select stars and measurements in field of 1 degree from given point (RA,DEC) is given here. Then one must to login on desired machine as user piguest and run program/script.
Of course program can be written in C/C++ or any other language for which interface to POSTGRES database exists.

3. Getting Started

After inspecting database through WWW interface, one wants to get data and analyse it. The simples way is to login on machine heplx40 as user piguest and run :

    psql 20050203_2 -U pidb_guest -h heplx43

This allows to access database and see for example table definitions , by running :

    \d frame
    \d stars
    \d measurements

Then one can run simple selection of stars :

    SELECT * FROM STARS WHERE ra>=( 9.02867043-(1.00/15.00) ) AND ra<= ( 9.02867043+(1.00/15.00) ) AND no_measurements>=80;

Then choose ID of one of the selected stars and see measurements :

    SELECT * FROM MEASUREMENTS WHERE star=42135;

Then one can run example script , which can be found in piguest home directory :

    cd ~
    ./list_stars.pl -radius=0.001

And this is good example of accessing pi-catalog.
Another example is example.pl script.

4. Big database

Big database containing catalogue of all nights since 20050701 .. is available from heplx40 machine by :

    psql 2004_2005 -U pidb_guest -h heplx47

or by editing list_stars.pl example script and changing line :

    $dbh = DBI->connect ( "dbi:Pg:dbname=20050203_2;host=heplx43", "pidb_guest", "");

to :

    $dbh = DBI->connect ( "dbi:Pg:dbname=2004_2005;host=heplx47", "pidb_guest", "");