The SURF commands

The SCUBA data reduction commands are summarized briefly in this section. On-line help for these commands can be accessed with scuhelp or by replying with ?? at any prompt.

There are six steps which need to be followed in order to produce the final coadded, but still uncalibrated, photometric result, namely reduce_switch, change_flat, flatfield, extinction, scuphot and scucat. In addition, data taken with the arrays may be corrected for sky noise variations by subtracting off the signal from surrounding bolometers using the remsky command. - see later in this section for a description of these commands.

The data reduction software takes the demodulated data as input and the format is yyyymmdd_dem_xxxx without the .sdf extension, for example, 19970711_dem_0025. Additional files called yyyymmdd_red_xxxx.sdf are produced by the on-line data reduction software and include preliminary signal information.

The SCUBA log command, sculog², can be run to give a log of all the observations in a directory. All the journal software (sculog, obssum, photsum, etc.) as well as reduce_switch and skydip recognise the concept of a data directory. This means that the data (demodulated or reduced) does not need to be present in the current directory - the tasks will search for data in the directory specified by the DATADIR environment variable as well as the current directory. Using the unix C-shell this can be achieved by:

% setenv DATADIR /wherever/data/19970706/dem

which would instruct obssum, say, to search for data in directory /wherever/data/19970706/dem. Help on the log commands can be accessed with the -h option:

% sculog -h
 
Usage: 
  sculog [-h] [-all]
Options:
  -h[elp]        This message
  -summary       Gives a one line summary of each file
  -all           Catalog all sdf files regardless of numeric range
  -begin nn      First scan number to be considered
  -end nn        Final scan number to be considered
  -demod         Only look at raw demodulated data files (ie _dem_)
  -reduced       Only look at files reduced on-line (ie _red_)
  -mode obs      Select observation modes
 
also
  --begin=nn     First scan number (note the -- prefix)
  --end=nn       Final scan number
  --mode=obs     Select observation modes
 
  Where nn is an integer and 'obs' is a comma delimited list of obsmodes.
  Use 'perldoc sculog' for more information.
Author:
  Tim Jenness (timj@jach.hawaii.edu)

The photsum command uses sculog to produce a brief description of each observation (like usum for UKT14). If the reduced data files are present then this summary will include signal and skydip tau values, e.g.,

% photsum -all -reduced
 #    HST    Source   Meas/Int  Am   Filter  SubInst Signal   S/N   Tau  Seeing
---  -----   -------  -------- ---- -------- ------- ------  -----  ---  ------
42   20:17   mars        1/5   1.09 450N:850 LONG   4.80e+00 279.5  0.052 1.376
                                             SHORT  3.10e-01 8.32
45   20:30   mars        1/5   1.07 450N:850 LONG   4.85e+00 375.7  0.044 1.376
                                             SHORT  1.69e+00 185.
46   20:33   mars        1/5   1.07 450N:850 LONG   4.86e+00 275.6  0.044 1.376
                                             SHORT  1.71e+00 116.
47   20:36   mars        1/5   1.06 350N:750 LONG   4.15e+00 518.0  0.045 1.376
                                             SHORT  5.35e-01 242.
48   20:40   mars        1/5   1.06 850S:PHO P1350  4.95e+00 458.5  0.045 0.487
49   20:43   mars        1/5   1.05 850S:PHO P2000  4.22e-01 282.9  0.045 0.487
**************
50   20:46   SKYDIP     10/20       450N:850 SHORT:  0.936          0.062 0.487
                                             LONG    0.211
--------------
**************
51   20:54   SKYDIP     10/20       350N:750 SHORT:  0.943          0.062 0.487
                                             LONG    0.411
--------------
64   22:38   B21122+390  1/20  1.08 850S:PHO P2000  2.74e-06 0.203  0.048 0.17
65   22:49   B21122+390  1/20  1.09 850S:PHO P2000  2.12e-05 1.786  0.044 0.124
66   22:59   B21122+390  1/20  1.10 850S:PHO P2000  2.50e-05 2.249  0.045 0.124
67   23:09   B21122+390  1/20  1.12 850S:PHO P2000  1.79e-05 1.829  0.047 0.124
68   23:19   B21122+390  1/20  1.13 850S:PHO P1350  1.14e-04 5.434  0.05  0.098
69   23:30   B21122+390  1/20  1.15 850S:PHO P1350  1.18e-04 5.280  0.047 0.098
72   23:47   mars        1/5   1.20 850S:PHO P2000  4.19e-01 415.3  0.046 0.096
73   23:51   mars        1/5   1.21 850S:PHO P1350  4.65e+00 720.6  0.046 0.096
74   23:55   mars        1/5   1.23 450N:850 LONG   4.93e+00 548.5  0.046 0.096
                                             SHORT  1.69e+00 187.
76   00:55   mars        1/5   1.53 350N:750 LONG   4.01e+00 633.3  0.051 0.144
                                             SHORT  4.51e-01 514.
78   01:02   B21122+390  1/20  1.46 350N:750 LONG   1.33e-04 4.697  0.046 0.144
                                             SHORT  4.39e-05 2.08
79   01:13   B21122+390  1/20  1.52 350N:750 LONG   1.11e-04 4.540  0.048 0.108
                                             SHORT  3.10e-05 1.71