We are pleased to announce the release of GBTIDL, version 2.8.
As of June 1, 2011, GBTIDL at all NRAO sites corresponds to version 2.8 and
includes the changes described in this note.
Getting Started
The starting point for GBTIDL documentation, bug reporting and tracking,
and discussion is http://gbtidl.nrao.edu/
A comprehensive User's Guide is available.
A new Quick Reference for version 2.8 is available.
New Features
o The online feature of GBTIDL has been modified to work with the new online
sdfits that fills data while the scan is in progress. That change will be
transparent to users except that the time GBTIDL takes to identify the
most recent online file after typing online is much shorter. Although the
online sdfits is now filling data while the scan is in progress, GBTIDL
must wait until the scan has completely before it can see any of the data
from the most recent scan. That happens automatically. Data for the most
recent scan should be viewable within 1 minute of the end of that scan,
independent of the length of the scan, for most spectrometer observing
modes.
o getcal - a new procedure to retrieve just the cal-switching signal from the
data. It is similar to gettp and requires that cal-switching is happening
in the indicated scan. The result is the average of
(data_with_cal - data_without_cal)/2.0
The system temperature is determined exactly as it is for all other GBTIDL
code. For frequency switched data you can use the sig_state argument to
indicate which signal state you want to use (the default is to use both).
o gettp - has two new keyword arguments: sig_state and cal_state. These allow
you to select only part of the data to use. The sig_state argument is
useful if you want to process frequency-switched data with gettp. The
cal_state argument is useful if simply want to get an average of just that
cal switching state.
o The distributed copy of the Goddard IDL Astronomy Library was updated using
the version available on 10 May 2011.
Bugs Fixed
o dcascii now uses more precision for the printed X-axis values (e.g. frequency)
o Selections of some floating point values did not work as advertised in the
User's Guide. In one case that was due to the typo in the User's Guide and
in another case it was due to a bug in the GBTIDL selection code. Both
errors have been fixed in this release.
Register as a GBTIDL user
Use the on-line registration form.
Running GBTIDL in Green Bank, Socorro, or Charlottesville:
At the Unix prompt, simply type gbtidl
Running your own copy of GBTIDL
IDL License
You must have an IDL license to run GBTIDL. IDL version 6.1 and later is
supported. If you don't have a license you can run GBTIDL remotely, using
the computers in CV or GB. See the GBTIDL homepage for details. IDL 6.3 or
later is needed for large file support on a Mac.
Download and Installation of GBTIDL
To obtain GBTIDL, download the files here
Create a directory for the installation and unzip the tar ball:
mkdir mygbtidl
mv gbtidl-2.8.tar.gz mygbtidl/.
cd mygbtidl
gzip -d gbtidl-2.8.tar.gz
tar -xvf gbtidl-2.8.tar
go to the newly created installation directory, 'gbtidl':
cd gbtidl
copy the file 'run_gbtidl' to 'gbtidl':
cp run_gbtidl gbtidl
edit the 'gbtidl' script to use the correct path to your installation of
idl. For example:
LOCAL_IDL=/usr/local/bin/idl
edit the 'gbtidl' script to replace "PLACE_INSTALLATION_DIR_HERE" with the
full path to the gbtidl executable script. It should then look something
like this:
export GBT_IDL_DIR=/home/mygbtidl/gbtidl
start GBTIDL:
./gbtidl
You may wish to add the installation directory to your Unix path.
