Appendix C
SCUBA2_MAPSTATS

The Picard recipe SCUBA2_MAPSTATS estimates the RMS and NEFD for a given observation.

The average NEP is calculated from the QL pipeline log file (log.nep) corresponding to the date and wavelength. The FCF (either from the file or the standard value) and mean transmission over the observation is used to convert this to a zenith NEFD (NEFD).

The input images are cropped to the given size (as specified in the FITS headers or via the MAP_HEIGHT and MAP_WIDTH recipe parameters) before the mean exposure time is derived, along with the mean/median noise and NEFD (RMS and NEFDs).

The parameters written out to log.mapstats are listed below:




Parameter

Description



UT

UT date including day fraction

HST

HST date and time stamp

Obs

observation number

Source

object name

Mode

observation mode (either daisy or pong)

FILTER

filter (wavelength)

El

mean elevation of observation

Airmass

mean airmass of observation

Trans

mean line-of-sight transmission

Tau225

mean zenith optical depth at 225 GHz, derived from WVM

telapsed

elapsed time of observation in seconds

texp

mean exposure time, derived from EXP_TIME NDF component (sec)

rms

RMS noise in map, obtained from median of error array

rms_units

RMS units

nefd

NEFD derived from combination of variance and exposure time images

nefd_units

NEFD units

mapsize

size (requested diameter) of input map (arcsec)

pixscale

pixel scale in arcsec

project

project ID

recipe

reduction recipe used

filename

name of input file