Class: Projection

Projection(a0, d0, angle)

Base class for oject providing projection functions

Constructor

new Projection(a0, d0, angle)

Parameters:
Name Type Description
a0 number reference coordinate on axis 1 in radians (float)
d0 number reference coordinate on axis 2 in radians (float)
angle number rotation in radians (float)
Source:

Methods

(abstract) absToRel(a, d) → {Object}

Computes the relative offset (xp, yp) in a linear plane, from an absolute (RA, DEC). Use xp and yp to retrieve the i_yp, i_yp pixel values
Parameters:
Name Type Description
a array right ascensions (float)
d array declinations (float)
Source:
Returns:
array of offsets x and y
Type
Object

iRaiDecToHMSDMS(ra, dec) → {Object}

returns RA/Dec in HMS/DMS
Parameters:
Name Type Description
ra number pixel coordinates on ra axis (int)
dec number pixel coordinates on dec axis (int)
Source:
Returns:
Object containing ra, dec coordinates
Type
Object

iRaiDecToRaDec(ra, dec) → {Object}

Returns RA/Dec in degrees from a coordinate in pixels
Parameters:
Name Type Description
ra number pixel coordinates on ra axis (int)
dec number pixel coordinates on dec axis (int)
Source:
Returns:
Object containing ra, dec coordinates
Type
Object

moduloDec(dec) → {number}

DEC is between -PI/2 and PI/2
Parameters:
Name Type Description
dec number DEC in radians (float)
Source:
Returns:
(float)
Type
number

moduloRa(ra) → {number}

RA is between 0 and 2PI
Parameters:
Name Type Description
ra number RA in radians (float)
Source:
Returns:
(float)
Type
number

raDecToiRaiDec(ra, dec) → {Object}

Returns a coordinate in pixels from RA/DEC in degrees
Parameters:
Name Type Description
ra number RA in degrees (float)
dec number DEC in degreess (float)
Source:
Returns:
Object containing iRa, iDec coordinates
Type
Object

(abstract) relToAbs(x, y) → {Object}

Computes the absolute (RA, DEC) from the relative linear offset given in the header
Parameters:
Name Type Description
x array array of offsets in X
y array array of offsets in Y
Source:
Returns:
an object containing ra/dec coordinates
Type
Object

(static) create(a0, d0, angle, type)

Factory function creating a projection object
Parameters:
Name Type Description
a0 number crval1 in radians (float)
d0 number crval2 in radians (float)
angle number rotation angle (float)
type ProjEnum type of projection
Source:
Returns: