SCUPHOT - Reduce SCUBA PHOTOM data

Description:

This routine reduces the data for a single sub-instrument from a PHOTOM observation. For each bolometer used to look at the source the data will be analysed as follows:-

• An ndf called $<$bolname$>$_map (e.g. h7_map) will be created in the OUT file to hold the coadded data from all the integrations. If the jiggle pattern points fit a 2-d rectangular pattern then these data will be arranged as a 2-d map suitable for plotting as an image. A 2-d parabola will be fitted to the coadded image and the results written in ASCII form to FILE. If an irregular jiggle pattern is used the map will take the form of a 1-D strip.

• Second, an ndf called $<$bolname$>$_peak (e.g. h7_peak) will be created in the OUT file to hold the fitted results to the data for each integration. The results stored are the fit peak, its variance and quality and they are held as a 1-d array suitable for plotting as a graph. The fit results are also written in ASCII form to FILE, as is the coadd of all the individual fits to the data.

Usage:

scuphot in analysis out file

Parameters:

ALLBOLS = LOGICAL (Read)

By default only the observed bolometers are processed (i.e. if you observed with H7 only H7 data will be stored). If ALLBOLS is set to true then all middle beam data is processed. This is useful for examining sky noise. Note that for 2 and 3 bolometer photometry ALLBOLS must be false to avoid weighting problems for the bolometers that were observed in the left or right beams.

ANALYSIS = CHAR (Read)

The method used to determine the peak for each integration. Either average or parabola. Parabola is not recommended at this time. Alternatively, all the samples can be propagated without processing (`samples') - this will give the same result for the signal as `average' (since `average' returns a smoothing of all the data) but for small datasets may give a more accurate measure of the error. The discrepancy is especially noticeable for calibration measurements where N_INTEGRATIONS may only be 6 - the noise statistics on 6 averaged numbers are less reliable than those of 6 $\times$ 9 numbers (assuming 9 samples per integration).

FILE = FILENAME (Write)

The name of the ASCII output file.

IN = NDF (Read)

The name of the input file containing demodulated (extinction corrected) SCUBA data.

MSG_FILTER = CHAR (Read)

Message output level. Allowed values are QUIET, NORM and VERB. Default is NORM. There are no verbose messages.

OUT = CHAR (Write)

The name of the HDS output file to contain the NDFs described above. This file will have the extension .sdf but this should not be specified in the name.

Examples:

scuphot o56_lon_ext average o56_lon_pht !

Process o56_lon_ext by averaging integrations. Do not write a text file containing the results.

Notes:

• ALLBOLS must be false for 2 and 3 bolometer photometry unless you know what you are doing.

• SCUPHOT can process JIGGLE/MAP data. The output is the signal for each integration for each bolometer. This is useful for checking sky removal and should not be used for performing on-source photometry on map data! This method can not be used for SCAN/MAP data.

Related Applications

SURF: scucat

Implementation Status:

Ideally scuphot should process MAP data on a per exposure basis. Currently only per integration is supported.