HorizontalFrames

class sofia_redux.scan.frames.horizontal_frames.HorizontalFrames

Bases: Frames

Initialize horizontal frames.

The horizontal frames extend standard equatorial based frames to include horizontal coordinates, offset from the observed source, and the zenith opacity (tau).

Attributes Summary

default_field_types	Used to define the default values for data arrays.
site	Return the site coordinates of the associated scan.

Methods Summary

calculate_equatorial()	Calculate the equatorial coordinates from the horizontal coordinates.
calculate_horizontal()	Calculate the horizontal coordinates from the equatorial coordinates.
calculate_parallactic_angle([lst, indices])	Calculate the cos(pa) and sin(pa) values.
equatorial_native_to_horizontal_offset(offset)	Convert native equatorial offsets to horizontal offsets.
equatorial_to_horizontal_offset(offset[, ...])	Convert equatorial offsets to horizontal offsets.
equatorial_to_native(equatorial[, indices, ...])	Convert equatorial coordinates to native (horizontal) coordinates.
get_absolute_native_coordinates()	Get absolute spherical (including chopper) coords in telescope frame.
get_absolute_native_offsets()	Return absolute spherical offsets in telescope frame.
get_base_native_offset([indices, offset])	Return equatorial native offsets of the frames from the scan reference.
get_equatorial(offsets[, indices, equatorial])	Return equatorial coordinates given offsets from the base equatorial.
get_equatorial_native_offset(position[, ...])	Return the horizontal offsets of a position relative to scan center.
get_horizontal(offsets[, indices, horizontal])	Return horizontal coordinates given offsets from the base horizontal.
get_horizontal_offset(position[, indices, ...])	Return the horizontal offsets of a position relative to scan center.
get_native_offset(position[, indices, offset])	Get the horizontal offsets for the given position.
get_parallactic_angle([indices])	Returns the tan of sin(position_angle), cos(position_angle).
horizontal_to_equatorial_offset(offset[, ...])	Convert a horizontal offset to an equatorial offset.
horizontal_to_native_equatorial_offset(offset)	Convert horizontal offsets to native equatorial offsets.
native_equatorial_to_native_offset(offset[, ...])	Convert native equatorial offsets to native (horizontal) offsets.
native_to_equatorial(native[, indices, ...])	Convert native (horizontal) coordinates to equatorial coordinates.
native_to_native_equatorial_offset(offset[, ...])	Convert native (horizontal) offsets to native equatorial offsets.
pointing_at(offset[, indices])	Applies pointing correction to coordinates via subtraction.
project(position, projector[, indices])	Project a position to offsets.
set_parallactic_angle(angle[, indices])	Sets the sin_pa and cos_pa parallactic angles.
set_zenith_tau(zenith_tau[, indices])	Set the zenith tau values of the frames.
validate()	Validate frame data after read.

Attributes Documentation

default_field_types

Used to define the default values for data arrays.

Returns a dictionary of structure {field: default_value}. The default values have the following effects:

type - empty numpy array of the given type. value - full numpy array of the given value. astropy.units.Unit - empty numpy array (float) in the given unit. astropy.units.Quantity - full numpy array of the given quantity.

If a tuple is provided, the array will have additional axes appended such that the first element gives the type as above, and any additional integers give additional axes dimensions, e.g. (0.0, 2, 3) would result in a numpy array filled with zeros of shape (self.size, 2, 3).

Returns:

fieldsdict

site

Return the site coordinates of the associated scan.

Returns:

GeodeticCoordinates

Methods Documentation

calculate_equatorial()

Calculate the equatorial coordinates from the horizontal coordinates.

This assumes that the object is tracked on sky, and uses scanning offsets on top of the tracking coordinates of the scan.

Returns:

None

calculate_horizontal()

Calculate the horizontal coordinates from the equatorial coordinates.

Returns:

None

calculate_parallactic_angle(lst=None, indices=None)

Calculate the cos(pa) and sin(pa) values.

Parameters:

lstastropy.units.Quantity

If provided, the Local Sidereal Time will be used to calculate the position angle from the site and equatorial coordinates. Otherwise, the parallactic angle will be calculated from the horizontal coordinates. If an array is provided, should be the same shape as indices.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices for which to calculate the parallactic angle. The default is all frames.

Returns:

None

equatorial_native_to_horizontal_offset(offset, indices=None, in_place=True)

Convert native equatorial offsets to horizontal offsets.

Rotates by -PA (position angle).

Parameters:

offsetCoordinate2D

The native equatorial (x, y) offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices to update. The default is all frames.

in_placebool, optional

If True, modify the coordinates in place. Otherwise, return a copy of the offsets.

Returns:

horizontal_offsetsCoordinate2D

equatorial_to_horizontal_offset(offset, indices=None, in_place=True)

Convert equatorial offsets to horizontal offsets.

Parameters:

offsetCoordinate2D

The equatorial (x, y) offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices to update. The default is all frames.

in_placebool, optional

If True, modify the coordinates in place. Otherwise, return a copy of the offsets.

Returns:

horizontal_offsetsCoordinate2D

equatorial_to_native(equatorial, indices=None, native=None)

Convert equatorial coordinates to native (horizontal) coordinates.

Parameters:

equatorialEquatorialCoordinates

The equatorial coordinates to convert.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices for which to calculate offsets. The default is all frames (not used by equatorial frames).

nativeSphericalCoordinates, optional

The native coordinates to populate. Will default to spherical coordinates if not provided.

Returns:

native_coordinatesHorizontalCoordinates

get_absolute_native_coordinates()

Get absolute spherical (including chopper) coords in telescope frame.

This is named getNativeCoords() in CRUSH

Returns:

coordinatesHorizontalCoordinates

get_absolute_native_offsets()

Return absolute spherical offsets in telescope frame.

This is named GetNativeOffset() in CRUSH

Returns:

offsetsCoordinate2D

The (x, y) native offsets.

get_base_native_offset(indices=None, offset=None)

Return equatorial native offsets of the frames from the scan reference.

Parameters:

indicesint or slice or numpy.ndarray (int or bool)

The frame indices for which to extract the offsets.

offsetCoordinate2D, optional

An optional coordinate object to hold the results.

Returns:

horizontal_offsetsCoordinate2D

get_equatorial(offsets, indices=None, equatorial=None)

Return equatorial coordinates given offsets from the base equatorial.

The return result (lon, lat) is:

lon = base_lon + (position.lon / cos(scan.lat)) lat = base_lat + position.lat

Parameters:

offsetsCoordinate2D

The (x, y) horizontal offsets of shape () or (shape,)

indicesnumpy.ndarray (int), optional

The frame indices that apply. The default is all indices.

equatorialEquatorialCoordinates, optional

The equatorial output frame. The default is the same as the frame equatorial frame.

Returns:

equatorialEquatorialCoordinates

get_equatorial_native_offset(position, indices=None, offset=None)

Return the horizontal offsets of a position relative to scan center.

The final return position is the sum of the position offsets, and the equatorial coordinates of the frame relative to the scan center.

Parameters:

positionCoordinate2D

The (x, y) horizontal offsets of shape () or (m,) giving the (lon, lat) offset positions. If not set, the default is to return the offsets relative to the scan equatorial position.

indicesint or numpy.ndarray (int), optional

The frame indices that apply of shape (n,) (if an array was used). The default is all indices.

offsetCoordinate2D, optional

An optional output array to store and return the coordinates.

Returns:

equatorial_offsetsCoordinate2D

An array containing the sum of the equatorial offsets of the frame data and the supplied positions. If multiple frame indices and multiple positions are supplied, the resulting coordinate shape will be (n, m). Otherwise, the result will be shaped as either (n,) or (m,) or () depending on if indices/position are singular.

get_horizontal(offsets, indices=None, horizontal=None)

Return horizontal coordinates given offsets from the base horizontal.

Parameters:

offsetsCoordinate2D

The (x, y) horizontal offsets of shape () or (shape,)

indicesnumpy.ndarray (int), optional

The frame indices that apply. The default is all indices.

horizontalHorizontalCoordinates, optional

The horizontal output frame. The default is a fresh frame.

Returns:

horizontalHorizontalCoordinates

get_horizontal_offset(position, indices=None, offset=None)

Return the horizontal offsets of a position relative to scan center.

Parameters:

positionCoordinate2D, optional

The (x, y) horizontal offsets.

indicesint or numpy.ndarray (int), optional

The frame indices that apply of shape (n,) (if an array was used). The default is all indices.

offsetCoordinate2D, optional

An optional output array to store and return the coordinates.

Returns:

horizontal_offsetsCoordinate2D

An array containing the sum of the horizontal offsets of the frame data and the supplied positions. If multiple frame indices and multiple positions are supplied, the resulting coordinate shape will be (n, m). Otherwise, the result will be shaped as either (n,) or (m,) or () depending on if indices/position are singular.

get_native_offset(position, indices=None, offset=None)

Get the horizontal offsets for the given position.

Parameters:

positionCoordinate2D

The (x, y) offsets.

indicesnumpy.ndarray (int), optional

The frame indices that apply. The default is all indices.

offsetCoordinate2D, optional

The coordinate object on which to store the offsets (returned).

Returns:

native_offsetsCoordinate2D

get_parallactic_angle(indices=None)

Returns the tan of sin(position_angle), cos(position_angle).

Parameters:

indicesnumpy.ndarray (int), optional

The frame indices. The default is all indices.

Returns:

angleastropy.units.Quantity (numpy.ndarray)

An array of angles of size (N,) or (indices.size,).

horizontal_to_equatorial_offset(offset, indices=None, in_place=True)

Convert a horizontal offset to an equatorial offset.

Parameters:

offsetCoordinate2D

The horizontal (x, y) offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices to update. The default is all frames.

in_placebool, optional

If True, modify the coordinates in place. Otherwise, return a copy of the offsets.

Returns:

equatorial_offsetsCoordinate2D

horizontal_to_native_equatorial_offset(offset, indices=None, in_place=True)

Convert horizontal offsets to native equatorial offsets.

Rotates by the position angle.

Parameters:

offsetCoordinate2D

The horizontal (x, y) offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices to update. The default is all frames.

in_placebool, optional

If True, modify the coordinates in place. Otherwise, return a copy of the offsets.

Returns:

native_equatorial_offsetsCoordinate2D

native_equatorial_to_native_offset(offset, indices=None, in_place=True)

Convert native equatorial offsets to native (horizontal) offsets.

Parameters:

offsetCoordinate2D

The native (x, y) equatorial offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices for which to calculate offsets. The default is all frames (not used by equatorial frames).

in_placebool, optional

If True, modify the coordinates in place. Otherwise, return a copy of the offsets.

Returns:

native_offsetsCoordinate2D

native_to_equatorial(native, indices=None, equatorial=None)

Convert native (horizontal) coordinates to equatorial coordinates.

Parameters:

nativeHorizontalCoordinates

The coordinates to convert.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices for which to calculate offsets. The default is all frames (not used by equatorial frames).

equatorialEquatorialCoordinates, optional

If not supplied, the returned coordinates will have a J2000 epoch. Otherwise, the equatorial coordinates provided will be populated.

Returns:

equatorial_coordinatesEquatorialCoordinates

native_to_native_equatorial_offset(offset, indices=None, in_place=True)

Convert native (horizontal) offsets to native equatorial offsets.

Parameters:

offsetCoordinate2D

The native (x, y) offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices for which to calculate offsets. The default is all frames (not used by equatorial frames).

in_placebool, optional

If True, modify the coordinates in place. Otherwise, return a copy of the offsets.

Returns:

native_equatorial_offsetsCoordinate2D

pointing_at(offset, indices=None)

Applies pointing correction to coordinates via subtraction.

Parameters:

offsetastropy.units.Quantity (numpy.ndarray)

An array of

indicesnumpy.ndarray (int), optional

The frame indices that apply. The default is all indices.

Returns:

None

project(position, projector, indices=None)

Project a position to offsets.

Parameters:

positionCoordinate2D

The (x, y) position.

projectorAstroProjector

The projector to store and determine the projected offsets.

indicesint or slice or numpy.ndarray (int or bool)

The frame indices to project.

Returns:

offsetsCoordinate2D

The (x, y) offsets.

set_parallactic_angle(angle, indices=None)

Sets the sin_pa and cos_pa parallactic angles.

Parameters:

angleint or float or numpy.ndarray or Quantity

The angle to set. If an array is supplied, must be the same size as indices.

indicesnumpy.ndarray (int), optional

The frame indices to set. The default is all indices.

Returns:

None

set_zenith_tau(zenith_tau, indices=None)

Set the zenith tau values of the frames.

Parameters:

zenith_taufloat or numpy.ndarray (float)

The zenith tau value(s).

indicesint or slice or numpy.ndarray (int or bool)

The frame indices to apply the values to. The default is all frames.

Returns:

None

validate()

Validate frame data after read.

Should set the validated (checked) attribute if necessary.

Returns:

None