Inappropriate EOP on the VLBA Correlator
Next: Introduction
VLBA TEST MEMO 69
Inappropriate EOP on the VLBA Correlator
R. C. Walker, V. Dhawan, W.
Brisken, J. Benson, L. Kogan, & J. Romney
National Radio Astronomy Observatory
Socorro, NM
October 6, 2005
Abstract:
A bug has been found in the job generator for the VLBA
correlator that caused it to use predicted rather than measured
Earth Orientation Parameters (EOP) between May 2003 and August
2005. The errors introduced often are sufficiently large to
adversely affect phase referencing observations and other
observations that rely on an accurate correlator model. The
nature of the problem and its impact are discussed in this
memo. Correcting data is straightforward using the new EOPS
option in the AIPS task CLCOR. Users just wishing to make
corrections without worrying about the gory details can consult
Section 2, or simply follow the
CLCOR help file. It has become apparent while dealing with this
problem that even occasional projects from outside the time
period of the bug have been correlated with poor EOP. Usually
this is because their job scripts were prepared too close to
the observe date. So any user depending on an accurate
correlator model may wish to check their EOP.
- Introduction
- Correcting Data - The Quick Recipe
- What Went Wrong?
- Effect on Data
- Tests Using Science Projects
- Targeted Test Observations of 2005 August 13
- Correcting Data - The Long Version with Full Explanations
- Improving the EOP Used on the VLBA Correlator
- Additional Issues
- Preventing Future Problems
- Bibliography
- About this document ...
Next: Introduction Craig Walker 2005-10-06
