Point Spread Functions¶
GalPaK provides the two most common PSF : Gaussian and Moffat.
You may use them as the psf argument of the Instrument, as described here.
Gaussian¶
All instruments use this PSF model by default, with their own configuration :
- class galpak.GaussianPointSpreadFunction(fwhm=None, pa=0, ba=1.0)[source]¶
The default Gaussian Point Spread Function.
- fwhm: float
Full Width Half Maximum in arcsec, aka. “seeing”.
- pa: float [default is 0.]
Position Angle of major-axis, anti-clockwise rotation from Y-axis, in angular degrees.
- ba: float [default is 1.0]
Axis ratio of the ellipsis, b/a ratio (y/x).
Moffat¶
- class galpak.MoffatPointSpreadFunction(fwhm=None, alpha=None, beta=None, pa=0, ba=1)[source]¶
The Moffat Point Spread Function
- fwhm if alpha is None: float [in arcsec]
Moffat’s distribution fwhm variable : http://en.wikipedia.org/wiki/Moffat_distribution
- alpha if fwhm is None: float [in arcsec]
Moffat’s distribution alpha variable : http://en.wikipedia.org/wiki/Moffat_distribution
- beta: float
Moffat’s distribution beta variable : http://en.wikipedia.org/wiki/Moffat_distribution
- pa: float [default is 0.]
Position Angle of major-axis, the anti-clockwise rotation from Y, in angular degrees.
- ba: float [default is 1.0]
Axis ratio of the ellipsis, b/a ratio (y/x).
Interface¶
In order to furthermore customize the PSF you want to use, you can create your own PSF class and use it in the instrument, it simply needs to implement the following interface :
