SSSC 18

Source subtraction and calibration

Logged on 27/09/09 06:55:09

Ahh.. The beauty of simulation. Subtracting the two known sources in the uv plane and calibrating for sinusoidal time-varying gains yields thermal noise (=numerical precision in this case).

I see that the image of the simualted field (previous map) is inverted. ... and Ian has commented on this. It can be fixed by rendered the python imshow() method with keyword origin='lower'

Next I'll perform the same step but put in a screwed up primary beam expression (just for kicks).

Data products

SSSC18_WSRT.MS.CORRECTED_DATA.channel.64ch.fits (header)

64x1x512x512 FITS cube, 4 planes are given below.

Image plane #0.

data range:	-2.15354e-09,1.84692e-09
mean:	4.3719e-12
sigma:	4.55481e-10
clipping:	95%
clip range:	-9.11207e-10,8.74153e-10

Image plane #1.

data range:	-1.91063e-09,2.08137e-09
mean:	5.23381e-12
sigma:	4.52767e-10
clipping:	95%
clip range:	-8.50253e-10,9.39131e-10

Image plane #2.

data range:	-2.13248e-09,2.14237e-09
mean:	6.90081e-12
sigma:	4.54445e-10
clipping:	95%
clip range:	-8.29989e-10,9.6929e-10

Image plane #3.

data range:	-1.80833e-09,2.23687e-09
mean:	-3.10819e-12
sigma:	4.4619e-10
clipping:	95%
clip range:	-7.89134e-10,1.0241e-09

G_diag.fmep

G_offdiag.fmep

.tdl.conf

Corrupted Primary Beam Expression

Logged on 27/09/09 07:05:55

Despite inserting an incorrect primary beam expression ((cos(min(100*fq*r,1.0881))**6) where "100" should be 65) there is no change in the thermal noise. Perhaps I didn't set this value large enough so that there was a discernable difference in the off centre point source flux suppressed by the primary beam and that that stated in the lsm. Will come back to this. Apologies for including I,Q,U,V. Is there a way to only include one polarisation in a purrlog (apart from not imaging all)?