X
g = 1 + h_2 T_lapse
amb
gconst
with
h1 = 2, h2 = -6.5 (note this h2 is defined differently to that in the previous equation),
gconst
See ‘Calibration of mm and sub-mm Photometers by Skydipping’, W.D.Duncan preprint and
‘Inversion of Sky Dips’, SCU/WDD/31.1/1093 for further details.
The fit can be made with ETAtel and/or b either fixed or varying. To allow one of these
parameters to vary it should be input to the routine with a value below zero. If the input
value is greater than zero then the routine will fix it at that for the fit.
Invocation
CALL
SCULIB_FIT_SKYDIP (CVAR, N_MEASUREMENTS, AIRMASS, J_MEASURED, J_VARIANCE,
SUB_WAVELENGTH, SUB_INSTRUMENT, SUB_FILTER, T_TEL, T_AMB, ETA_TEL_IN, B_IN,
ETA_TEL_FIT, B_FIT, TAUZ_FIT, REXISQ, TAU_ERROR, ETA_ERROR, B_ERROR, RESIDUAL, SIGMA,
STATUS)
Arguments
CVAR = LOGICAL (Given)
flag to govern whether to use a fixed
variance (true) or the actual variance. The fixed variance is the mean of the actual variances.
N_MEASUREMENTS = INTEGER (Given)
the number of SKYDIP measurements
AIRMASS
(N_MEASUREMENTS) = REAL (Given)
the airmasses at which the measurements were
made
DATA (N_MEASUREMENTS) = REAL (Given)
the measured sky brightness
temperatures
VARIANCE (N_MEASUREMENTS) = REAL (Given)
the variance on DATA
SUB_WAVELENGTH = REAL (Given)
the wavelength of the measurements
SUB_INSTRUMENT =
CHARACTER()
(Given)
the name of the sub-instrument used
SUB_FILTER =
CHARACTER()
(Given)
the name of the filter used
T_TEL = REAL (Given)
the telescope temperature (K)
T_AMB = REAL (Given)
the ambient temperature (K)
ETA_TEL_IN = REAL (Given)
if
= 0 then this will the ETAtel
assumed in the fit. if
0 then ETAtel will be allowed to vary in the fit.
B_IN = REAL (Given)
if
=0 then this value of b will
be assumed in the fit. if
0 then b will be allowed to vary in the fit.
ETA_TEL_FIT = REAL (Returned)
the result for ETAtel
B_FIT = REAL (Returned)
the result for b
TAUZ_FIT = REAL (Returned)
the fitted result for tauz
REXISQ = REAL (Returned)
the reduced chi square of the fit
TAU_ERROR = REAL (Returned)
error in the tau
ETA_ERROR = REAL (Returned)
error in eta_tel
B_ERROR = REAL
(Returned)
error in B
RESIDUAL = DOUBLE (Returned)
Absolute difference between the
model and the fit.
SIGMA = DOUBLE (Returned)
standard deviation of the difference
between the model and the fit.
STATUS = INTEGER (Given and returned)
Global status