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, clockwise rotation from Y of ellipse, 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=None, ba=None)[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, the clockwise rotation from Y of ellipse, 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 :
