csviscube

Computes visibility cube for a given IACT array and time period.

Synopsis

This script computes a visibility cube which is a sky cube spanned by Right Ascension, Declination and zenith angle that provides the number of hours that a given position on the sky is observable under a given zenith angle by an IACT array during a given time period.

For the moment, the script takes into account:

  • a Sun constraint, specified as a minimum zenith angle of the Sun (hidden parameter sunzenith). If the Sun is higher in the sky than this zenith angle the corresponding times are excluded

  • a Moon constraint, specified as a minimum zenith angle of the Moon (hidden parameter moonzenith). If the Moon is higher in the sky than this zenith angle the corresponding times are excluded

  • a constraint on the lunar illumination (hidden parameter maxfli). If the Moon has an illumination that is equal or larger than this fraction the corresponding times are excluded

On output, the script will provide a FITS file containing the visibility cube. In addition, the FITS file will also contain a VISIBILITY extension in form of a binary table that provides a number of parameters, such as the positions of the Sun and the Moon, the fraction of lunar illumation and the Dark Time as function of time.

Use the example script show_viscube.py to display a visibility cube.

General parameters

tmin [time]

Start time of observation (UTC string, JD, MJD or MET in seconds).

tmax [time]

Stop time of observation (UTC string, JD, MJD or MET in seconds).

(mjdref = 51544.5) [real]

Reference Modified Julian Day (MJD) for MET.

geolon [real]

Geographic longitude of the IACT array in degrees.

geolat [real]

Geographic latitude of the IACT array in degrees.

(sunzenith = 105.0) [real]

Minimum Sun zenith angle for observations in degrees.

If the Sun is higher in the sky than the specified zenith angle, the corresponding times are excluded from the visibility cube.

(moonzenith = 90.0) [real]

Minimum Moon zenith angle for observations in degrees.

If the Moon is higher in the sky than the specified zenith angle, the corresponding times are excluded from the visibility cube.

(maxfli = 0.4) [real]

Maximum fraction of lunar illumination.

If the Moon has an illumination that is equal or larger than this fraction, the corresponding times are excluded from the visibility cube.

outfile [file]

Output visibility cube file.

(binsz = 1.0) [real]

Visibility cube pixel size in degrees/pixel.

(dz = 1.0) [real]

Visibility cube zenith angle bin size in degrees.

(zmax = 60.0) [real]

Maximum zenith angle of the visibility cube in degrees.

Standard parameters

(publish = no) [boolean]

Specifies whether the visibility cube should be published on VO Hub.

(chatter = 2) [integer]
Verbosity of the executable:

chatter = 0: no information will be logged

chatter = 1: only errors will be logged

chatter = 2: errors and actions will be logged

chatter = 3: report about the task execution

chatter = 4: detailed report about the task execution

(clobber = yes) [boolean]

Specifies whether an existing visibility cube file should be overwritten.

(debug = no) [boolean]

Enables debug mode. In debug mode the executable will dump any log file output to the console.

(mode = ql) [string]

Mode of automatic parameters (default is ql, i.e. “query and learn”).

(logfile = csviscube.log) [filename]

Log filename.