Pointing models (ctapointing.pointingmodel)

Classes providing telescope pointing models and functionality to fit these models to pointing observations.

API

ctapointing.pointingmodel Package

class ctapointing.pointingmodel.MechanicalModelHESS(**kwargs: Any)

The HESS standard pointing model.

__init__(config=None, parent=None, **kwargs)

Parameters:

• config (traitlets.loader.Config) – Configuration specified by config file or cmdline arguments. Used to set traitlet values.

• parent (Tool or Component) – If a Component is created by another Component or Tool, you need to pass the creating Component as parent, e.g. parent=self. This makes sure the config is correctly handed down to the child components. Do not pass config in this case.

• kwargs – Traitlets to be overridden. TraitError is raised if kwargs contains a key that does not correspond to a traitlet.

amp_non_perp_alt

amplitude of non-perpendicularity altitude axis

amp_non_vert_az

amplitude of non-verticality azimuth axis

amp_se_alt

amplitude of shaft encoder error altitude

amp_se_az

amplitude of shaft encoder error azimuth

amp_sin_2az

amplitude of sin(2az) effect

bending_hor

horizontal camera bending

bending_vert

vertical camera bending

camera_offset_hor

horizontal camera offset

camera_offset_vert

vertical camera offset

camera_offset_vert_reverse

vertical camera offset (reverse)

const_camera_rot

constant camera rotation

const_focal_length

constant focal length

const_refraction

constant refraction

get_corrected_pointing(nominal_pointing)

Calculates the corrected pointing for a (array-like) sky coordinate in the AltAz system.

Implements the 19 parameters HESS mechanical pointing model.

Parameters:

nominal_pointing (SkyCoord) – Nominal pointing of the telescope.

Returns:

corrected_pointing – Corrected pointing of the telescope, according to the model predicition.

Return type:

SkyCoord

mix_sin_2az

mixing angle of sin(2az) effect

offset_se_az

offset of shaft encoder azimuth

phase_non_vert_az

phase of non-verticality azimuth axis

phase_se_alt

phase of shaft encoder error altitude

phase_se_az

phase of shaft encoder error azimuth

phase_sin_2az

phase of sin(2az) effect

class ctapointing.pointingmodel.NullModel(**kwargs: Any)

A pointing model without any corrections applied.

__init__(config=None, parent=None, **kwargs)

Parameters:

• config (traitlets.loader.Config) – Configuration specified by config file or cmdline arguments. Used to set traitlet values.

• parent (Tool or Component) – If a Component is created by another Component or Tool, you need to pass the creating Component as parent, e.g. parent=self. This makes sure the config is correctly handed down to the child components. Do not pass config in this case.

• kwargs – Traitlets to be overridden. TraitError is raised if kwargs contains a key that does not correspond to a traitlet.

get_corrected_pointing(nominal_pointing)

Calculates the corrected pointing for a single nominal pointing position.

In case of the NullModel, output is identical to input.

Parameters:

nominal_pointing (SkyCoord) – Nominal pointing of the telescope.

Returns:

corrected_pointing – Corrected pointing of the telescope, according to the model prediction.

Return type:

SkyCoord

class ctapointing.pointingmodel.PointingModel(**kwargs: Any)

Super class that holds the parameters of a pointing model, provides a function to calculate pointing corrections for a particular coordinate, and enables loading of a model from the database or a file.

__init__(config=None, parent=None, **kwargs)

Parameters:

• config (traitlets.loader.Config) – Configuration specified by config file or cmdline arguments. Used to set traitlet values.

• parent (Tool or Component) – If a Component is created by another Component or Tool, you need to pass the creating Component as parent, e.g. parent=self. This makes sure the config is correctly handed down to the child components. Do not pass config in this case.

• kwargs – Traitlets to be overridden. TraitError is raised if kwargs contains a key that does not correspond to a traitlet.

classmethod from_config(**kwargs)

Read a pointing model from either configuration file or database. Either the path of a configuration file (‘input_url’) or a database collection (‘collection’) must be provided.

Parameters:

• input_url (str or Path) – path of the configuration file.

• name (str) – name of the camera (as in PointingCamera.name). When loading the configuration from file, can be set to check that the configuration with the correct name is loaded. When loading from database, is used to identify the correct database record.

• uuid (str) – UUID of the camera (as in PointingCamera.uuid). When loading the configuration from file, can be set to check that the configuration with the correct UUID is loaded. When loading from database, is used to identify the correct database record.

• collection (str) – name of the database collection from which configuration is read

• database (str) – name of the database in which the collection is stored

Returns:

camera

Return type:

PointingCamera object

get_corrected_pointing(nominal_pointing)

Calculates the corrected pointing for a single nominal pointing position. Must be implemented by child class.

get_parameters_as_dict(strip_units=False) → dict

Return a list of parameter values (with or without units)

get_parameters_as_list(strip_units=False) → list

Return a list of parameter values (with or without units)

name

model name

update_parameter_values(parameters: dict | list) → None

Set a model or parts of a model from individual arguments or a dictionary

Parameters:

parameters (dict) – dictionary of model parameters names (keys) and parameter values

uuid

UUID of Pointing Model

valid_from

start date of validity of model

valid_until

end date of validity of model

class ctapointing.pointingmodel.PointingModelFitterLid(**kwargs: Any)

Pointing model fitting class.

distance_goal

fit distance goal

fixed_parameters

list of parameters fixed during fitting

classmethod from_config(**kwargs)

Read a PointingModelFitter configuration from either configuration file or database. Either the path of a configuration file (‘input_url’) or a database collection (‘collection’) must be provided.

Parameters:

• input_url (str or Path) – path of the configuration file.

• name (str) – name of the SpotExtractor (as in SkyFitter.name). When loading the configuration from file, can be set to check that the configuration with the correct name is loaded. When loading from database, is used to identify the correct database record.

• uuid (str) – UUID of the camera (as in PointingCamera.uuid). When loading the configuration from file, can be set to check that the configuration with the correct UUID is loaded. When loading from database, is used to identify the correct database record.

• collection (str) – name of the database collection from which configuration is read

• database (str) – name of the database in which the collection is stored

Returns:

fitter

Return type:

PointingModelFitter object or None

max_num_fit_iterations

maximum number of fit iterations

name

name of PointingModelFitter

residual_cut

cut value for spot outlier removal

uuid

UUID of PointingModelFitter

class ctapointing.pointingmodel.PointingModelFitterSky(**kwargs: Any)

Pointing model fitting class.

distance_goal

fit distance goal

fixed_parameters

list of parameters fixed during fitting

classmethod from_config(**kwargs)

Read a PointingModelFitter configuration from either configuration file or database. Either the path of a configuration file (‘input_url’) or a database collection (‘collection’) must be provided.

Parameters:

• input_url (str or Path) – path of the configuration file.

• name (str) – name of the SpotExtractor (as in SkyFitter.name). When loading the configuration from file, can be set to check that the configuration with the correct name is loaded. When loading from database, is used to identify the correct database record.

• uuid (str) – UUID of the camera (as in PointingCamera.uuid). When loading the configuration from file, can be set to check that the configuration with the correct UUID is loaded. When loading from database, is used to identify the correct database record.

• collection (str) – name of the database collection from which configuration is read

• database (str) – name of the database in which the collection is stored

Returns:

fitter

Return type:

PointingModelFitter object or None

max_num_fit_iterations

maximum number of fit iterations

name

name of PointingModelFitter

residual_cut

cut value for spot outlier removal

uuid

UUID of PointingModelFitter

ctapointing.pointingmodel.plot_pointing_models(model_list, plot_difference=False, subtract_mean=False)

Plot the pointing corrections on the sky. model_list is a list of PointingModel objects. If plot_difference is True, the difference w.r.t. the first model is plotted.

returns references to the two figures.

Functions

plot_pointing_models(model_list[, ...])

Plot the pointing corrections on the sky.

Classes

PointingModel(**kwargs)	Super class that holds the parameters of a pointing model, provides a function to calculate pointing corrections for a particular coordinate, and enables loading of a model from the database or a file.
NullModel(**kwargs)	A pointing model without any corrections applied.
MechanicalModelHESS(**kwargs)	The HESS standard pointing model.
PointingModelFitterLid(**kwargs)	Pointing model fitting class.
PointingModelFitterSky(**kwargs)	Pointing model fitting class.

Class Inheritance Diagram