Tmt night

IRIS Exposure Time Calculator

The IRIS Exposure Time Calculator (ETC) is a tool to assist with the development of science cases that involve observations with IRIS (TMT's first light diffration limited near-IR (1-2.4 µm) imager and Integral Field Spectrograph).

At this time the tool or user interface for the ETC is still being developed and tested.

The planned rollout date - 31st October 2018

Link to the ETC instruction page.


Instrument Setup
The IFS is serial behind the imager. Light passes through the imager filter and into the IFS.
Source Properties
Expected Performance and Atmospheric Conditions
Point spread functions (PSF) are defined in each bandpass with varying atmospheric conditions, AO guide star configuration, Zenith angle, and field position across the IRIS focal plane and used to approximate different expected observing conditions.

The spectrograph PSF is always on-axis. Users can specify field locations across the four imagers.