Atacama Pathfinder EXperiment APEX
Observing time calculator V 3.3
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Integration Time Calculator

Heterodyne receivers By entering the atmospheric temperature (some 10 degrees below the ground temperature at Chajnantor), the (average) elevation of the source, the receiver temperature, required σ (in K), and the spectral resolution, the on-source integration time can be estimated. Also the total time is calculated assuming toff=ton and a system observing efficiency of 0.4, i.e. ttotal=(ton + toff)/0.4.The system efficiency takes into account both system and setup+calibration overheads. System overheads include telescope movements, software overheads, observing mode efficiency, etc. Setup+calibration overheads include source acquisition, pointing, focus, receiver tuning and calibration scans.
Frequency [GHz]
Redshift Z
Sky Frequency [GHz]
Trec [K]
PWV [mm H2O]
Tatm [K]
Zenith opt depth
Source elevation [deg]
RMS [K]
FFTS [Number of channels]
Vel. resolution Δv [km/s]
Tsys [K]
Position switching on-time Total PSW time [s]
Beam switching on-time Total BSW time [s]
     

 

RMS Calculator