SeeingData

class rubin_sim.site_models.SeeingData(start_time, seeing_db=None, offset_year=0)

Bases: object

Read the seeing data from disk and return appropriate FWHM_500 value at a given time. This is for use in simulations only. Otherwise data would come from the EFD.

Parameters:

start_timeastropy.time.Time

The time of the start of the simulation. The seeing database will be assumed to start on Jan 01 of the same year.

seeing_dbstr or None, optional

The name of the seeing database. If None (default), this will use the simsee_pachon_58777_13.db file in the ‘data’ directory of this package. Other available seeing databases from sims_seeingModel include: seeing.db (the original, less-variable, 3 year seeing database) simsee_pachon_58777_13.db (the current default, 10 year, seeing database) simsee_pachon_58777_16.db (a similar, but slightly offset, 13 year seeing database) For more info on simsee_pachon_58777_*, see https://github.com/lsst/sims_seeingModel/issues/2

offset_yearfloat, optional

Offset into the cloud database by ‘offset_year’ years. Default 0.

Methods Summary

__call__(time)	Get the FWHM_500 value for the specified time.
config_info()	Report information about configuration of this data.
read_data()	Read the seeing information from disk.

Methods Documentation

__call__(time)

Get the FWHM_500 value for the specified time.

Parameters:

timeastropy.time.Time

Time in the simulation for which to find the ‘current’ zenith seeing values. The difference between this time and the start_time, plus the offset, will be used to query the seeing database.

Returns:

float

The FWHM_500(”) closest to the specified time.

config_info()

Report information about configuration of this data.

Returns:

OrderedDict

read_data()

Read the seeing information from disk.

The default behavior is to use the module stored database. However, an alternate database file can be provided. The alternate database file needs to have a table called Seeing with the following columns:

seeingId

int : A unique index for each seeing entry.

s_date

int : The time (in seconds) from the start of the simulation, for the seeing observation.

seeing

float : The FWHM of the atmospheric PSF (in arcseconds) at zenith.