lsst.sims.ocs.environment.seeing_model module

class lsst.sims.ocs.environment.seeing_model.SeeingModel(time_handler)

Bases: future.types.newobject.newobject

Handle the seeing information.

This class deals with the seeing information that was previously produced for OpSim version 3.

Initialize the class.

Parameters:time_handler (TimeHandler) – The instance of the simulation time handler.

calculate_seeing(delta_time, filter_name, airmass)

Calculate the geometric and effective seeing values.

Parameters:

• delta_time (int) – The time (seconds) from the start of the simulation.
• filter_name (str) – The single character filter name for the calculation.
• airmass (float) – The airmass for the calculation.

Returns:

tuple – The FWHM 500nm, FWHM Geometric and FWHM Effective seeing values.

get_seeing(delta_time)

Get the seeing for the specified time.

Parameters:delta_time (int) – The time (seconds) from the start of the simulation. Returns:float – The seeing (arcseconds) closest to the specified time.

initialize(environment_config, filters_config)

Configure the seeing information.

This function gets the environment and filters configuration, calculates the FWHM system seeing at zenith and creates the seeing information from the appropriate database. 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 (units=seconds) since the start of the simulation for the seeing observation.

seeing

float : The FWHM of the atmospheric PSF (units=arcseconds).

Parameters:

• environment_config (Environment) – The configuration instance for the environment.
• filters_config (Filters) – The configuration instance for the filters.

set_topic(th, topic)

Set the seeing information into the topic.

Parameters:

• th (TimeHandler) – A time hadnling instance.
• topic (SALPY_scheduler.scheduler_seeingC) – An instance of the seeing topic.

AIRMASS_CORRECTION_POWER = 0.6

FILTER_WAVELENGTH_CORRECTION_POWER = 0.3

RAW_SEEING_WAVELENGTH = 500

SEEING_DB = 'seeing.db'

Filename of the internal seeing observation database.