Last Update: 1st August 2019

A Manual of Time Estimator


This page is designed to explain the usage of the time estimators for line observations. There are two types of time estimators: one is for position switching observations, the other is for On-The-Fly observations. Applicants who aim to observe multi-line and/or multi-targets are requested to estimate the observing time for all the lines and targets. After the time estimation, applicants should append (i.e., copy and paste) the results after the Science and Technical Justification.

Links to the Time Estimators

For position switch observations:
Time Estimator for PSW

For On-The-Fly observations:
Time Estimator for OTF

A Manual of Time Estimator for Position Switching Observations

Since the time estimator uses JavaScript, please enable JavaScript. If JavaScript is forbidden in your browser, the message will be printed on "* Messages:" field.

The meaning of each parameter of Time Estimator for Position Switch (PSW) Observations is explained in this section. If parameters you input are wrong, the error message will pop up.

The time estimator for PSW consists of 10 parameters:

By clicking the "Calc" button, the calculation will be performed, and a summary of input parameters and results are shown at the bottom of the page unless the parameter(s) is/are false. The meaning of the results is as follows:

Note that
1. "Total obs. time" includes OFF integration and telescope slewing time, and NOT includes the overheads for pointing and tuning.
You must multiply the overhead factor of 1.3 to Total obs. time_sm to obtain final total observing time.

2. Scan number = (Number of Beams) * (Number of Sequences: on-off or on-on is one sequence), NOT includes polarization.
The resultant "Scan number for one ON-point" is a number of scans to be observed for one beam (polarization). Therefore, if you intend to obtain two polarizations simultaneously, you need to include two polarizations in one "Device Table" when you make observing scripts.

Please copy and paste the input parameters and the results at the end of Science and Technical Justifications.
You can get correct display by enclosing these text with \begin{verbatim*} and \end{verbatim*} in LaTeX file.

A Manual of Time Estimator for On-The-Fly Observations

Since the time estimator uses JavaScript, please enable JavaScript. If JavaScript is forbidden in your browser, the message will be printed on "* Messages:" field.

The explanation for Time Estimator for OTF Observations is described in this section. For detailed information about On-The-Fly observations, applicants should refer to OTF Observations with the 45-m telescope. Especially in choosing observing parameters, refer to Determining Parameters and Sensitivities.

In order to calculate the observing time for OTF, there are 15 parameters to be filled:

When you click "calc" button, the observing time will be calculated with your input parameters, and a summary of input parameters and results are shown at the bottom of the page. The meaning of the results is as follows:

The total observing time for your OTF observation can be calculated using "9. ttot(OBS)" and "15. dTa*_sm". Assume the rms noise which you are going to achieve is Trms, number of observing script to achieve Trms (N) can be calculated as

N=(Trms/dTa*sm)2.

Therefore, the total on-source time can be written as

Nttot(OBS).

Finally, multiplying the overhead factor (f), you can get the total observing time Tobs. The overhead factor is 1.3 except for FOREST whose overhead factor is 1.4.

Tobs= fNttot(OBS).

Please copy and paste the input parameters and the results at the end of Science and Technical Justifications. You can get correct display by enclosing these text with \begin{verbatim*} and \end{verbatim*} in LaTeX file.