Coordinates (ctapointing.coordinates)
The ctapointing.coordinates module contains the implementation of coordinate transformations of ICRS/AltAz coordinates into coordinates in the pointing camera chip plane, and transformations of ICRS/AltAz coordinates into the frame of the telescope science camera.
API
ctapointing.coordinates Package
- class ctapointing.coordinates.ScienceCameraFrame(*args, copy=True, representation_type=None, differential_type=None, **kwargs)
ScienceCamera coordinate frame.
Represents a science camera coordinate frame. This frame is similar to a ctapipe.coordinates.CameraFrame, but allows for horizontal and vertical tilts and offsets of the system w.r.t. the 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 SkyCameraFrame 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 ground - the y coordinate points towards West when the TelescopeSystem points to the horizon in Northern direction and no tilts/rotations 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 camera 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]
- 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
- offset_x
A frame attribute
Default: 0.0 m
- offset_y
A frame attribute
Default: 0.0 m
- rotation
A frame attribute
Default: 0.0 deg
- telescope_pointing
A frame attribute
No default value
- tilt_x
A frame attribute
Default: 0.0 deg
- tilt_y
A frame attribute
Default: 0.0 deg
- class ctapointing.coordinates.SkyCameraFrame(*args, copy=True, representation_type=None, differential_type=None, **kwargs)
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).
- 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
Classes
|
SkyCamera coordinate frame. |
|
ScienceCamera coordinate frame. |
Class Inheritance Diagram
