# set_backscal¶

sherpa.astro.ui.set_backscal(id, backscale=None, bkg_id=None)

Change the area scaling of a PHA data set.

The area scaling factor of a PHA data set is taken from the BACKSCAL keyword or column, but it can be changed once the file has been loaded.

Parameters
• id (int or str, optional) – The identifier for the data set to use. If not given then the default identifier is used, as returned by get_default_id.

• backscale (number or array) – The scaling factor.

• bkg_id (int or str, optional) – Set to identify which background component to set. The default value (None) means that this is for the source component of the data set.

See also

get_backscal()

Return the area scaling of a PHA data set.

set_areascal()

Change the fractional area factor of a PHA data set.

set_exposure()

Change the exposure time of a PHA data set.

Notes

The function does not follow the normal Python standards for parameter use, since it is designed for easy interactive use. When called with a single un-named argument, it is taken to be the backscale parameter. If given two un-named arguments, then they are interpreted as the id and backscale parameters, respectively. The remaining parameters are expected to be given as named arguments.