The purpose of these pages is to accompany computer lab exercises for
working with interferometric
data. The software used is the
collection of IDL scripts, which
reduce, calibrate, and model NPOI data.
The idea is to use the software to follow the steps outlined in these
pages, and to experiment further in order to learn about real
interferometric data and its analysis.
It is the intention of these classes to learn about principle aspects
of interferometric data reduction, not so much about a specific software.
Each interferometer, be it SUSI, IOTA, PTI, CHARA, or GI2T, have their
own packages and even strategies or pecularities, which are not subject to
this course. But there are common features, and those will hopefully
be demonstrated in the following.
The author of this lab session and OYSTER asks you to keep in mind
that the software is not guarenteed and that the instructions in this
document may (and are probably) not complete. He would therefore appreciate
any comments sent to firstname.lastname@example.org.
Note for Windows Users
OYSTER has not been released for Windows. However, you should be
able to perform the
calibration, imaging, and modeling exercises with this version since they
don't require access to the external library. It is important not to use
the get_data procedure; use restore,'1997-05-01.xdr' instead!
This restores the file 1997-05-01.cha, which means that you do not
use the reduce command, but begin imaging and modeling with this
already calibrated data set. If you want to re-calibrate it, remove the
existing calibration first (using Undo|Reset for each of the data types
VisSq, TripleAmp, and TriplePhase).
You can copy the three OYSTER installation directories (oyster, catalogs,
atmospheres) to the hard disk, or run the software directly from the CD-ROM.
When running the IDL graphical user interface (created when double-clicking
the IDL icon on the desktop after installing IDL), set the working directory
to c:\oyster\lab\data and the startup file to c:\oyster\oyster.pro. Modify full
paths as needed. These preferences can be found under File|Preferences. Then
restart IDL and it should be running OYSTER after startup is complete.