create_deviation

ccdproc.create_deviation(ccd_data, gain=None, readnoise=None, disregard_nan=False)

Create a uncertainty frame. The function will update the uncertainty plane which gives the standard deviation for the data. Gain is used in this function only to scale the data in constructing the deviation; the data is not scaled.

Parameters:

ccd_dataCCDData

Data whose deviation will be calculated.

gainQuantity or None, optional

Gain of the CCD; necessary only if ccd_data and readnoise are not in the same units. In that case, the units of gain should be those that convert ccd_data.data to the same units as readnoise. Default is None.

readnoiseQuantity or None, optional

Read noise per pixel. Default is None.

disregard_nan: boolean

If True, any value of nan in the output array will be replaced by the readnoise.

add_keywordstr, Keyword or dict-like, optional

Item(s) to add to metadata of result. Set to False or None to completely disable logging. Default is to add a dictionary with a single item: The key is the name of this function and the value is a string containing the arguments the function was called with, except the value of this argument.

Returns:

ccdCCDData

CCDData object with uncertainty created; uncertainty is in the same units as the data in the parameter ccd_data.

Raises:

UnitsError

Raised if readnoise units are not equal to product of gain and ccd_data units.