The Heterodyne Integration Time Calculator (ITC) – is web-based tool for calculating required integration times for Heterodyne observations. The Integration Time Calculator can be accessed via the following links:

- Time required for target RMS
- In this mode you can enter your desired sensitivity (1
*σ*RMS*T*_{A}*). The calculator will determine the “integration time” required per point in your map and from this calculate the total “elapsed” time required to perform the requested observation.

- In this mode you can enter your desired sensitivity (1
- RMS expected in elapsed time
- If you would like to start with the total “elapsed” time available for the observation, you should use this mode. The calculator will determine the corresponding “integration time” per point and then estimate the sensitivity.

- RMS for integration time per point
- If you want to specify the “integration time” per point, select this mode. The calculator will determine the time required to complete the whole observation and an estimate of the sensitivity achievable.

- Considerations for Strong Continuum Sources
- Special considerations need to be taken into account concerning overheads and the integration time on source for targets with a strong continuum such as the moon, the Sun, or planetary atmospheres.

The help for the heterodyne integration time calculator can be found here.