SpeX Observation Calculator
SpeX: 0.7-5.3 Micron Medium-Resolution Spectrograph and Imager
NASA InfraRed Telescope Facility(IRTF), Institute for Astronomy, University of Hawaii
SpeX Observer Documentation Technical Documentation

SpeX Observation Calculator (May 2020)

This form can be used to estimate:

  1. The limiting fluxes.
  2. The integration time needed to reach a requested signal-to-noise.
  3. The signal-to-noise from an input source flux, temperature, and integration time.
Click here for the User Instructions.
Simple guide for using ETC in each observing mode.
Contact Mike Connelley for further information or assistance.

Quantity to be estimated:
Select Observing Mode:
Slit width (arcsec):
Seeing (FWHM) in arcsec at 2.2 microns: Required for all
Required Signal-to-Noise ratio: Required for Limiting Flux, Total ITIME
Single frame integration time (sec): Required for all
Total integration time(sec): Required for Limiting Flux, Signal-to-Noise
Source Flux at 2.2 microns: Required for Total ITIME, Signal-to-Noise
Source blackbody temperature (K): Required for Total ITIME, Signal-to-Noise