Combining Bias Frames

  Combination of the bias frames is straight forward: filters used and integration times do not play a role, and in most cases the bias frames can be treated with the same weight. The default keyword setting for the bias combining is displayed in Table 3.4.

 

CCD_IN input name ? table of input frames

BS_TYP descriptor value * exposure type to check, if any

BS_SIG yes|no no create sigma image

BS_MET comb. method maxrej type of combining operation

BS_DEL yes|no no delete cal. frames afterwards

BS_STA mean|median|mode mode correct. by Mode/Median/Mean

BS_EXP yes|no no scale by exposure time

BS_SCA yes|no no scale by MMM

BS_OFF yes|no no add offset from MMM

BS_WEI yes|no yes use a weighted average

BS_SEC area [<,<:>,>] area for finding MMM

BS_RAN real,real -99999,99999 valid pixel range

BS_CLP real 3.,3. low/high sigma clipping factor

BS_NUL real NULL(2) value for rejections