• The contour intervals are
  • 1, 2, 3, 4, 5, 10, 25, 50 and 75% of peak at 850um and
  • 2, 4, 6, 8, 10, 25, 50 and 75% of peak at 450um.
• This star is clearly extended both at 850 and 450um.

IRC+10216 is extended at 850 micron because of its unsually large and bright CO envelope, but can be observed without problems with a chop throw of 60" or larger. It is also variable at 850 microns, and probably at 450 microns also. However, the scatter in the data at 450 microns is too large to fit a curve to, and hence IRC10216 CANNOT BE USED FOR 450 MICRON CALIBRATION. If you need to calibrate your 450 micron data and have no other calibrator, we suggest you use the general FCF information posted here. The 850 micron fits for peak and integrated fluxes against modified julian date, along with their residuals, are shown below.

	Peak flux	Integrated flux
Best fit
Residuals
Formulae (Y in decimal year)	S (Jy) = 5.40 + 0.40sin (2π (Y - 1999.22)/1.70)	S (Jy) = 8.70 + 0.85sin (2π (Y - 1999.22)/1.70)
(Y in MJD)	S (Jy) = 5.40 + 0.40sin (2π (Y - 51260)/621.1)	S (Jy) = 8.70 + 0.85sin (2π (Y - 51260)/621.1)