MoffatPSF¶
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class
gunagala.psf.
MoffatPSF
(model=None, shape=2.5, **kwargs)[source]¶ Bases:
gunagala.psf.FittablePSF
,astropy.modeling.functional_models.Moffat2D
Class representing a 2D Moffat profile point spread function.
Used to calculate pixelated version of the PSF and associated parameters useful for point source signal to noise and saturation limit calculations.
Parameters: - FWHM : astropy.units.Quantity
Full Width at Half-Maximum of the PSF in angle on the sky units
- shape : float, optional
Shape parameter of the Moffat function, must be > 1, default 2.5
- pixel_scale : astropy.units.Quantity, optional
Pixel scale (angle/pixel) to use when calculating pixellated point spread functions or related parameters. Does not need to be set on object creation but must be set before before pixellation function can be used.
Notes
Smaller values of the shape parameter correspond to ‘wingier’ profiles. A value of 4.765 would give the best fit to pure Kolmogorov atmospheric turbulence. When instrumental effects are added a lower value is appropriate. IRAF uses a default of 2.5.
Attributes: - n_pix: astropy.units.Quantity
Effective number of pixels
Attributes Summary
param_names
shape
Shape parameter of the Moffat function, see Notes. Attributes Documentation
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param_names
= ('amplitude', 'x_0', 'y_0', 'gamma', 'alpha')¶
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shape
¶ Shape parameter of the Moffat function, see Notes.
Returns: - shape : float
Shape parameter value.