Emerson II method

To remove the dual beam signature from ``Emerson II'' data, rebinned images of each chop configuration must be generated (they can be coadds of lots of observations). These images must have the same map centre, the same pixel scale, the same dimensions and must be regridded in the same coordinate frame as the chop (RJ for RJ, RB and GA data, PL or RD for moving sources). Fig. shows examples of four dual beam images of M82.

Figure: 4 dual beam images of M82. The chop throws are 20 arcsec RA chopping, 30 arcsec RA chopping, 20 arcsec dec chopping and 30 arcsec dec chopping.

Once these images have been generated, they can be processed by remdbm:

% remdbm o8?_lon_reb.sdf -out=m82
Starting monoliths...Done
Loop number 1
Chop: PA=90 THROW=20
 
Doing forward transformation
 
Loop number 2
Chop: PA=90 THROW=30
 
Doing forward transformation
 
Loop number 3
Chop: PA=0 THROW=20
 
Doing forward transformation
 
Loop number 4
Chop: PA=0 THROW=30
 
Doing forward transformation
 
Maximum difference between estimates of the same Fourier component is
0.02414273.
 
Doing inverse transformation
 
Result stored in m82
%

Note the use of shell wildcards. The final image can be seen in Fig. .

Figure: Final image of M82 after single beam restoration.