annul_ap - create a annular aperture object.

Calling Sequence

[aperture]=annul_ap(out_diameter,in_diameter)

Parameters

• out_diameter : the outer diameter of the annular aperture in meters.
• in_diameter : the inner diameter of the annular aperture in meters.
• aperture : the annular aperture constructed.

Description

create a annular aperture object.

Examples

	number=256;
	wavelength=1e-6;
	pixscl=0.1;sz=number*pixscl;
	dwf=begin(sz,wavelength);
	ap=annul_ap(sz,sz/2);
	dwf=aperture_transform(dwf,ap);
	dwf_fits(dwf,"annul_ap");
 

Author

Chen jingyuan, Gan guangyong (IAPCM, Beijing,China.)

See Also

circle ,   rectang ,   hex_ap ,   spid_annul_ap ,   til_hex_ap ,   aperture_transform ,   aperture ,