Observing Time calculator

Observing time calculator

ON/OFF Integration time estimator V 7.3
Use this calculator for on-off observations. If you are planning on-the-fly mapping, you should instead use the dedicated OTF Calculator

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.

System overheads include telescope movements, software overheads, observing mode efficiency, etc. Setup + calibration overheads include source acquisition, pointing, focus, receiver tuning and calibration scans. Note about overheads.

For an overview of the atmospheric transmission and the possible backend configurations for each receiver, check our instrument setup tool.

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Heterodyne receiver:
Tuning Freq: [GHz]
Line Freq [+6 & -2 GHz from tuning]: [GHz]
Side Band:
Full resolution Δv [ channels] : [km/s]
Manual resolution Δv: [km/s]
pwv : [mm H2O]
Source elevation: [deg]
rms (0 [K]) : [mK]
Tau (@ elev deg) 19081.93
Transmission (@ elev deg) 0
Trec [K] 72.5
Tsys [K] (source elev deg) INF
TsysImage [K] (source elev deg) 72.5
Beam [arcsec] 27
Position Switching On time 0.000 [s]
Position Switching Off time 0.000 [s]
Position Switching OverHead time 0.000 [s]
Total Position Switching time 0.000 [s]
Beam Switching On time 0.000 [s]
Beam Switching Off time 0.000 [s]
Beam Switching OverHead time 0.000 [s]
Total Beam Switching time 0.000 [s]

When you are satisfied with your time estimate, please copy and paste this text in your proposal time justification:

We have used the ON-OFF observing time calculator at APEX V7.3 to estimate the total time needed to achieve our goal. Using NFLASH230 tuned to 231 GHz in the , selecting a spectral resolution of 0 km/s and assuming a typical source elevation of deg and a typical PWV of mm, we could get down to a noise of 0 mK[Ta*] in 0 seconds (including telescope and calibration overheads).

Recent changes

2021-02-237.3Trec for SEPIA345 updated according to the results obtained during the commissioning of the instrument in 2020, Trec NFLASH updated with the full band range
2020-10-137.2Added transmission value, the proposal text use the PWV value selected in the form (before use a default value per instrument), the input rms value is in mK (before was K)
2020-10-087.1Full velocity resolution values updated
2020-07-107.1Values to estimate the overhead have been updated. The time estimation have been split in ON, OFF and Overhead (System, calibration,pointing and focus). Message with the estimation result added at the end
2020-05-187.0Overhead parameters updated
2020-03-136.1.2NFLASH230/345 Trec file modified added a point in the limit of the band. Overhead NFLASH230 changed, use the same values than FLASH
6.1.2shows RMS value in mK unit too
2020-02-256.1.1NFLASH460 modified to 2 polarization, change in number of channels availables in NFLASH460, SEPIA180, SEPIA345
2020-02-136.1No changes in computation. Added FE names NFLASH230, NFLASH460
2018-09-106.0.5No changes in computation. Updated FE names (SEPIA180, SEPIA660. Added table with tuning ranges per FE. Added warning messages when user inputs incorrect setups
2018-08-316.0.4Includes updates for 2SB SEPIA-B9 after installation and commissioning: Trx curves, sideband rejection and extended tuning range [583-724 GHz]
2018-07-026.0.3Updates with new SEPIA-B9 setup, new tunning range and change from DSB to 2SB
2018-03-216.0.2LASMA receiver added
2017-09-066.0.1New version 6.0.1, Fix a bug in off time estimation for integration time calculator V6.0
2017-08-306.0New version 6.0 available. New set of overhead parameters per instrument, measured from data obtained in 2016.
SEPIA-B7 added, The specification values for SEPIA-B7 are estimates and will need to be updated after successful installation and commissioning