Apertures
All apertures will rely on a position and the shape parameters.
aperture = Aperture(x0, y0, shape_params...)The position can be pixels or sky coordinates. The sky coordinate positions utilize SkyCoords.jl and WCS.jl for conversion.
Sky coordinates are not supported yet.
See Pixel Convention - The origin is the bottom-left with (1, 1) being the center of the pixel.
Circular Apertures
These apertures are parametrized by radius.
Photometry.Aperture.CircularAperture — TypeCircularAperture(x, y, r)
CircularAperture([x, y], r)A circular aperture.
A circular aperture with radius r. r must be greater than or equal to 0.
Examples
julia> ap = CircularAperture(0, 0, 10)
CircularAperture(0, 0, r=10)Photometry.Aperture.CircularAnnulus — TypeCircularAnnulus(x, y, r_in, r_out)
CircularAnnulus([x, y], r_in, r_out)A circular annulus with inner radius r_in and outer radius r_out. 0 ≤ r_in ≤ r_out.
Examples
julia> ap = CircularAnnulus(0, 0, 5, 10)
CircularAnnulus(0, 0, r_in=5, r_out=10)Elliptical Apertures
These apertures are parametrized by the semi-major axis a, semi-minor axis b and position angle in degrees counter-clockwise from the positive x-axis θ
Photometry.Aperture.EllipticalAperture — TypeEllipticalAperture(x, y, a, b, θ)
EllipticalAperture([x, y], a, b, θ)An elliptical aperture with semi-major axis a, semi-minor axis b, and position angle θ. a and b must be ≥ 0, θ is measured in degrees counter-clockwise the standard x-axis.
Examples
julia> ap = EllipticalAperture(0, 0, 4, 2, 35)
EllipticalAperture(0, 0, a=4, b=2, θ=35°)Photometry.Aperture.EllipticalAnnulus — TypeEllipticalAnnulus(x, y, a_in, a_out, b_out, θ)
EllipticalAnnulus([x, y], a_in, a_out, b_out, θ)An elliptical annulus with inner semi-major axis a_in, outer semi-major axis a_out, outer semi-minor axis b_out, and position angle θ. a_out ≥ a_in ≥ 0 and b_out must be ≥ 0, θ is measured in degrees counter-clockwise the standard x-axis.
b_in will automatically be calculated from (a_in / a_out) * b_out. Note this may cause a type instability.
Examples
julia> ap = EllipticalAnnulus(0, 0, 4, 10, 5, 45)
EllipticalAnnulus(0.0, 0.0, a_in=4.0, a_out=10.0, b_in=2.0, b_out=5.0, θ=45.0°)Rectangular Apertures
These apertures are parametrized by side-length a, side-length b, and position angle in degrees counter-clockwise from the positive x-axis θ.
API/Reference
Photometry.Aperture.AbstractAperture — TypeThe abstract super-type for Apertures
Photometry.Aperture.mask — Functionmask(::AbstractAperture; method=:exact)Return an array of the weighting of the aperture in the minimum bounding box. For an explanation of the different methods, see aperture_photometry.
Photometry.Aperture.cutout — Functioncutout(::AbstractAperture, data)Get the cutout of the aperture from the data. This will handle partial overlap by padding the data with zeros.