phot.background.mmm_dao

phot.background.mmm_dao(sky, highbad=None, min_nsky=20, maxiter=50, readnoise=0)

Estimate a sky value with the iterative MMM-DAO algorithm.

Notes

Prefer sky_fit for routine use. This implementation is slower and may change in the future.

MMM-DAO is a robust sky estimator based on the MMM modification of DAOFIND in DAOPHOT. See Section 2.2 of Stetson (1987) <https://ui.adsabs.harvard.edu/abs/1987PASP...99..191S/abstract>_.

Parameters

sky : array - like

Sky values, usually the image after object masking or subtraction.

highbad : float or None = None

Optional value that limits the upper side of the initial symmetric interval. The current implementation applies it as min(cut1, highbad - skymid). None leaves that interval unchanged. The annotation still accepts bool for compatibility, although this branch uses the value arithmetically. Default is None.

min_nsky : float or int = 20

Minimum number of sky values. Default is 20 (minsky in DAOPHOT MMM).

maxiter : int = 50

Maximum number of iterations. Default is 50.

readnoise : float = 0

Image read noise. Default is 0.

Returns

sky : float

Estimated sky value.