SkyCameraFrame

class ctapointing.coordinates.SkyCameraFrame(*args, copy=True, representation_type=None, differential_type=None, **kwargs)

Bases: BaseCoordinateFrame

SkyCamera coordinate frame.

Represents a camera coordinate frame with a fixed orientation w.r.t. a TelescopeFrame.

The coordinate frame can be - tilted w.r.t. the Telescope frame by angles

tilt_x (in the vertical direction, with positive tilt_x meaning that the CameraFrame is tilted towards positive altitude), tilt_y (in the horizontal direction, with positive tilt_y meaning that the CameraFrame is tilted towards positive azimuth)

rotated around the axis perpendicular to the CameraFrame’s plane, with positive angles meaning counterclock-wise rotation
scaled by the focal length
shifted by offsets offset_x and offset_y.

When viewed from the telescope towards the sky, - the x coordinate points towards the zenith - the y coordinate points towards East when the TelescopeSystem points to the horizon in Northern direction and no tilts have been applied.

Gnomonic projection of the spherical TelescopeFrame to the planar SkyCameraFrame is properly accounted for (no small-angle approximation is applied).

focal_length

Focal length of the CCD as a unit quantity (usually meters)

Type:: u.Quantity[length]

rotation

Rotation angle of the camera (0 deg in most cases)

Type:: u.Quantity[angle]

tilt_x

Tilt of the camera w.r.t. the telescope pointing in vertical direction

Type:: u.Quantity[angle]

tilt_y

tilt of the camera w.r.t. the telescope pointing in horizontal direction

Type:: u.Quantity[angle]

telescope_pointing

Pointing direction of the telescope as SkyCoord in AltAz

Type:: SkyCoord[AltAz]

obstime

observation time

Type:: astropy.Time

location

observatory location

Type:: astropy.EarthLocation

pressure

atmospheric ground-level pressure

Type:: astropy.Quantity[pressure]

temperature

atmospheric ground-level temperature

Type:: astropy.Quantity[temperature]

The latter four parameters are needed for proper transformation from/to

equatorial sky coordinates (ICRS).

Attributes Summary

`default_differential`	Default representation for differential data (e.g., velocity)
`default_representation`	Default representation for position data
`focal_length`	A frame attribute
`frame_attributes`
`frame_specific_representation_info`	Mapping for frame-specific component names
`location`	A frame attribute
`name`
`obstime`	A frame attribute
`offset_x`	A frame attribute
`offset_y`	A frame attribute
`pressure`	A frame attribute
`rotation`	A frame attribute
`telescope_pointing`	A frame attribute
`temperature`	A frame attribute
`tilt_x`	A frame attribute
`tilt_y`	A frame attribute

Attributes Documentation

default_differential: Default representation for differential data (e.g., velocity)

default_representation: Default representation for position data

focal_length

A frame attribute

Default: 1.0 m

frame_attributes = {'focal_length': <astropy.coordinates.attributes.QuantityAttribute object>, 'location': <astropy.coordinates.attributes.EarthLocationAttribute object>, 'obstime': <astropy.coordinates.attributes.TimeAttribute object>, 'offset_x': <astropy.coordinates.attributes.QuantityAttribute object>, 'offset_y': <astropy.coordinates.attributes.QuantityAttribute object>, 'pressure': <astropy.coordinates.attributes.QuantityAttribute object>, 'rotation': <astropy.coordinates.attributes.QuantityAttribute object>, 'telescope_pointing': <astropy.coordinates.attributes.CoordinateAttribute object>, 'temperature': <astropy.coordinates.attributes.QuantityAttribute object>, 'tilt_x': <astropy.coordinates.attributes.QuantityAttribute object>, 'tilt_y': <astropy.coordinates.attributes.QuantityAttribute object>}

frame_specific_representation_info: Mapping for frame-specific component names

location

A frame attribute

No default value

name = 'skycameraframe'

obstime

A frame attribute

No default value

offset_x

A frame attribute

Default: 0.0 m

offset_y

A frame attribute

Default: 0.0 m

pressure

A frame attribute

No default value

rotation

A frame attribute

Default: 0.0 deg

telescope_pointing

A frame attribute

No default value

temperature

A frame attribute

No default value

tilt_x

A frame attribute

Default: 0.0 deg

tilt_y

A frame attribute

Default: 0.0 deg

property default_differential: Default representation for differential data (e.g., velocity)

property default_representation: Default representation for position data

focal_length

A frame attribute

Default: 1.0 m

property frame_specific_representation_info: Mapping for frame-specific component names

location

A frame attribute

No default value

obstime

A frame attribute

No default value

offset_x

A frame attribute

Default: 0.0 m

offset_y

A frame attribute

Default: 0.0 m

pressure

A frame attribute

No default value

rotation

A frame attribute

Default: 0.0 deg

telescope_pointing

A frame attribute

No default value

temperature

A frame attribute

No default value

tilt_x

A frame attribute

Default: 0.0 deg

tilt_y

A frame attribute

Default: 0.0 deg