Reduction extension items

When running PRESENT you'll notice some strange names are given under the ``Item'' column. These are the names of the extension items stored in your data frames (at least they are for NDFs anyway, other formats use other names). Most of their meanings are fairly obvious as they correspond to the CCDSETUP parameters with similar names.

• FTYPE: The frame type (TARGET, BIAS, FLAT, DARK or FLASH).
• FILTER: The filter name (any unique string).
• TIMES.DARK: The dark count exposure time.
• TIMES.FLASH: The pre-flash exposure time.
• DIRECTION: The readout ``direction''.
• BOUNDS.START1: The first row/column of the first bias strip.
• BOUNDS.END1: The last row/column of the first bias strip.
• BOUNDS.START2: The first row/column of the second bias strip.
• BOUNDS.END2: The last row/column of the second bias strip.
• EXTENT.MINX: Lower X value of the useful CCD section.
• EXTENT.MAXX: Upper X value of the useful CCD section.
• EXTENT.MINY: Lower Y value of the useful CCD section.
• EXTENT.MAXY: Upper Y value of the useful CCD section.
• ADC: The analogue to digital conversion factor.
• RNOISE: The readout noise (ADUs).
• DEFERRED: The deferred charge value.
• SATURATION: The saturated pixel count (ADUs).