Data Reduction for AGES using LIVEDATA and GRIDZILLA

This page is designed to complement the comprehensive AUDS Data Reduction Instructions developed by Lister Staveley-Smith and Mark Calabretta

The process for reducing AGES data is identical to reducing AUDS data, except that we use longer scans, so it is imperative to read their instructions before proceeding.

Gridzilla and Livedata are distributed as part of the ATNF package of AIPS++. Originally when Mark Calabretta set up a working version here at Arecibo it was only available from the machine MOFONGO, so users had to ssh into MOFONGO before being able to run them. There are steps being taken to make this available to the whole NAIC network, but at the time of writing, some work and some don't. To be on the safe side users are advised to continue to use MOFONGO until further notice.

The AGES account has already been set up to run the most current version  of AIPS++ (v 1.9 Build 852) and it will tell you this when you login as AGES. To start LIVEDATA type:

% livedata

The GUI has changed slightly since the AUDS Data Reduction webpage was written (see the screenshot below). The main difference is that the ALFA configuration is now called AUDS.  The AUDS observing technique is similar enough to our mapping technique that the same reduction techniques can be applied.

livedata screenshot

CAUTION: The LIVEDATA display uses over 768 lines on your display and is NOT resizable. In order to display LIVEDATA properly you will need to make sure that your display can handle at least 1000 lines and is set up to do so.

All raw data resides in the /share/pservfer.sda3/wappdata directory. So set the 'Read directory' to this. A file filter can be applied to isolate all the AGES files by setting it to *a1961*. BEWARE THAT THE LEAPFROG AND ZOA OBSERVATIONS ALSO SHARE THIS PROJECT ID SO BE SURE TO KNOW WHICH FILES YOU'RE GOING TO PROCESS.

All processed data are stored in the /share/ages/drift_files directory under the appropriately dated directory. If the dated directory does not exist you will have to create it. So set the 'Write directory' to be /share/ages/drift_files/DATE (where DATE is replaced by the date of the observations, e.g. 20041125 for Nov 25th 2004. Livedata outputs SDFITS format files which can then be gridded using GRIDZILLA.

To accommodate our longer scans the 'Max Cycles' box and 'Box Size' both need to be set so that they are AT LEAST as big as your scan period, measured in integrations. The conversion is simplified by the fact that we are integrating every second. We are performing 1200 second scans, so as you can see 'Max Cycles' and 'Box Size' have been set to 1220.

Once LIVEDATA has reduced all the files you are ready for GRIDZILLA.

This page was written and is maintained by Robbie Auld. Page was last updated on 28/11/2004