Noise as a function of time for a single bolometer

The rms noise ( \ensuremath{\sigma_\ensuremath{\mathrm{}}}) of the data obtained with a single bolometer is related to the on-source integration time ( \ensuremath{t^\ensuremath{\mathrm{}}_\ensuremath{\mathrm{\ensuremath{\sigma_\ensuremath{\mathrm{}}}}}}) in a given direction of the sky through

  $\displaystyle \ensuremath{\sigma_\ensuremath{\mathrm{}}}= \frac{\ensuremath{\ma...
...mathrm{}}_\ensuremath{\mathrm{\ensuremath{\sigma_\ensuremath{\mathrm{}}}}}}}},
$ (1)
where \ensuremath{\mathrm{NEFD}} is the noise equivalent flux density of the bolometer, $\ensuremath{A}\simeq 1/\sin(\ensuremath{\mathrm{el}})$ the airmass and \ensuremath{\tau_\ensuremath{\mathrm{zen}}} the zenith atmospheric opacity.