General Monitoring: PWV monitor

This plot displays PWV values from CRIRES fits, and from X-SHOOTER and UVES standard stars.

A set of dedicated sky observations is executed regularly on CIRES, in order to measure the current PWV content of the atmosphere. For CRIRES, this is OB #200179115 ("PWV_5050p4"). The output data are analyzed on the fly by a routine which fits the telluric emission lines to a model. The results are collected in the tables linked behind "calista". That table has a column with plots ("ps") which can be used to check the quality of the fit. The fitted PWV values are also often written into the nightlogs. The fitting routine, and its integration into operations, has been implemented by Alain Smette. This method is called "FIT" in the QC1 database.

For VISIR, there is a similar procedure (based on OB #200154321, "SkySpectrum_MR_BurstMode". Its result are however inconsistent with the results from the other three instruments and are therefore not plotted here. They are stored in the QC1 database, you can browse and plot them using the links under "Information and research".

UVES has regular flux standard star measurements (usually at the begin of a night). The telluric absorption lines in the pipeline product RED_STD_REDL of the 860 setting are analyzed by a routine written by Reinhard Hanuschik. It calculates the equivalent width of the telluric absorption lines, and transforms these values into PWV values using a curve-of-growth. This method is called "WLAMBDA" in the QC1 database.

Finally, X-SHOOTER takes every few hours a telluric standard star, in all three arms. The products from the VIS arm are analyzed in a way similar to UVES. The X-Shooter PWV values are also collected here.

All values are stored in a QC1 database table and plotted here. All routines (parser, standard star processing, plotter) are called once per hour. The plot is expected to be up-to-date within that time-scale, provided new input data are available. Usually the pipeline processing of the standard star data is also up-to-date within one hour. That part has been implemented by Reinhard Hanuschik.

Plot #2 is a closeup of plot #1, emphasizing data values below 5 mm.