• 15 August, 2001 - Present:
  Data was taken with the L-wide receiver on August 12-15, 2001 using the "spider scan" routine. A low frequency set of data was taken (1175,1300,1375,1415 MHz) and a high frequency set (1415,1550,1610,1666 MHz). The data results are for the average of the two polarizations (Stokes I/2). The southwest quadrant of the reflector had not yet had it's final adjustment when the August data was taken. The surface rms went from 5.5 mm rms (before) to < 1.8 mm after the final adjustment. So the August data had 3/4 of the dish with an rms < 1.8 mm and 1/4 of the dish with an rms of about 5.5 mm. In September, 2001 the southwest quadrant adjustments were finished and a few sources were remeasured.
  Information on the new gain curves is available here.

• 11 Jan, 2001 - August, 2001:
  Large scale adjustments were made to the surface of the primary reflector between 20 Dec, 2000 and 11 Jan, 2001. Beginning the 26 Feb and continuing through June, 2001 a variety of calibration sources were observed using the L-narrow receiver. A fit was then made to the data, with the results given below. Please note that the data set is incomplete (particularly for southern sources - see the plot below)!
  The gain was computed using the source flux and cal values for all sources. The residual (actually just |data-fit|) is plotted versus azimuth and zenith angle. Each measurement is an arrow with the length proportional to the residual of the fit (1 division = 0.4 K/Jy). The angle from the vertical is proportional to the gain/gainMax (for all measurements). The angle is scaled so that 180 degrees (pointing down) is 50% of the max gain. On the plot, up is north and to the left is west (azimuth location for source rising). Circles are drawn every 5 degrees in za, and rays from the center are every 30 degrees. The az,za for each point is at the base of the arrow. The maximum, average, and rms gain (K/Jy) in 5 degree steps was computed all then data and then for 5 deg za steps.
  • The gain curve and residual plot can be found here
  • System temperature

• 01 Jan, 2000 - 20 Dec, 2000:
  These measurements are from data taken between April - October of 2000.
  The gain was computed using the source flux and cal values for all sources and then plotted versus azimuth and zenith angle. Each measurement is an arrow with the length proportional to the gain (1 division = 5 K/Jy). The angle from the vertical is proportional to the gain/gainMax (for all measurements). The angle is scaled so that 180 degrees (pointing down) is 50% of the max gain. On the plot, up is north and to the left is west (azimuth location for source rising). Circles are drawn every 5 degrees in za, and rays from the center are every 30 degrees. The az,za for each point is at the base of the arrow. The maximum, average, and rms gain (K/Jy) in 5 degree steps was computed all then data and then for 5 deg za steps.
  Note that for the L-Narrow, the OLD cal values of 1.85 and 1.91 were used to generate these curves!
  The system temperature, and SEFD:
  • Average gain versus azimuth and zenith angle, by source
  • System temperature versus azimuth and zenith angle, by source
  • G/T for polarization A versus azimuth and zenith angle, by source
  • The bottom line - computing the L-narrow gain

• Before 31 October 1999:
  These measurements were taken between June - July of 1999. Note that for the L-Narrow, the OLD cal values of 1.85 and 1.91 were used to generate these curves!
  • Calibration info for the L-band receivers BEFORE October, 1999 (or so)

• 15 August, 2001 - Present:
  New values for the L-narrow noise diodes were found on 28 January, 2002. These values apply to the gain curves from 15 August, 2001 onwards. Information on the new values can be found here.
• 18 December, 2001 - 15 August, 2001:
  On 18 December, 2000, the L-Narrow cals were re-measured. Information on the measured temperatures can be found here.
• Before 18 December, 2001:
  Prior to 18 December, 2000, the L-narrow noise diode values were assumed to be 1.85 & 1.91 for A & B polarizations, respectively, at all frequencies. This means that gain curves obtained before 18 Dec 2000 assume old cal values.

• More information on calibration techniques can be found in Chris Salter's "Note relevant to Spectral Line User's", which can be found here.
• More info on the calibration of both L-narrow and other Arecibo receivers, go to Phil Perrilat's home page (here).
• A description of the Stokes parameterization of the Arecibo main beam and first side-lobe can be found here (Heiles, et.al 2001 PASP 113, 1247).
• A description of the Mueller Matrix parameters for radio telescopes can be found here (Heiles, et.al 2001 PASP 113, 1274).
• A short introduction to digital spectropolarimetry written be Carl Heiles can be found here (Heiles 2001 PASP 113, 1243).

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