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 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.
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