Struct marlu::pos::radec::RADec

pub struct RADec {
    pub ra: f64,
    pub dec: f64,
}

A struct containing a Right Ascension and Declination. All units are in radians.

Note that the serialised units are degrees and are automatically converted when serialising/deserialising.

Fields

ra: f64

Right ascension [radians]

dec: f64

Declination [radians]

Implementations

impl RADec

pub fn from_radians(ra: f64, dec: f64) -> RADec

Make a new RADec struct from values in radians.

pub fn from_degrees(ra: f64, dec: f64) -> RADec

Make a new RADec struct from values in degrees.

pub fn new(ra_rad: f64, dec_rad: f64) -> RADec

👎Deprecated: use RADec::from_radians instead

Make a new RADec struct from values in radians.

pub fn new_degrees(ra_deg: f64, dec_deg: f64) -> RADec

👎Deprecated: use RADec::from_degrees instead

Make a new RADec struct from values in degrees.

pub fn to_hadec(self, lst_rad: f64) -> HADec

Given a local sidereal time, make a new HADec struct from a RADec.

pub fn from_hadec(hadec: HADec, lst_rad: f64) -> Self

Given a local sidereal time, make a new RADec struct from a HADec.

pub fn weighted_average(radecs: &[Self], weights: &[f64]) -> Option<Self>

From a collection of RADec coordinates and weights, find the average RADec position. The lengths of both collection must be the same to get sensible results. Not providing any RADec coordinates will make this function return None.

This function accounts for Right Ascension coordinates that range over 360 degrees. If the right ascension coordinates span a huge range (e.g. 0, 90, 180, 270), None is returned.

The average position is found by converting the RADec coordinates (“spherical coordinates”) to cartesian coordinates (direction cosines), performing the average, then converting the average back to spherical. The results have been verified with scipy.optimize (a sample program is provided at the bottom of this file) and online calculators. When coordinates are widely separated, the average can appear to have strange values due to them falling on great circles.

pub fn to_lmn(self, phase_centre: RADec) -> LMN

Get the LMN direction cosines from an RADec and a phase centre.

Derived using “Coordinate transformations” on page 388 of Synthesis Imaging in Radio Astronomy II.

pub fn separation(&self, b: Self) -> f64

Calculate the distance between two sets of coordinates [radians].

pub fn from_mwalib_phase_center(context: &MetafitsContext) -> Option<RADec>

Given an mwalib::MetafitsContext, make an Option<RADec> from the (ra|dec)_phase_center_degrees if these are available, otherwise None.

pub fn from_mwalib_tile_pointing(context: &MetafitsContext) -> RADec

Given an mwalib::MetafitsContext, make a RADec from the (ra|dec)_tile_pointing_degrees.

pub fn from_mwalib_phase_or_pointing(context: &MetafitsContext) -> RADec

Given an mwalib::MetafitsContext, make a RADec from the (ra|dec)_phase_center_degrees if these are available, otherwise use the (ra|dec)_tile_pointing_degrees.

Trait Implementations

impl Clone for RADec

fn clone(&self) -> RADec

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RADec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for RADec

fn default() -> RADec

Returns the “default value” for a type.

impl Display for RADec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq<RADec> for RADec

fn eq(&self, other: &RADec) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for RADec

impl StructuralPartialEq for RADec