STIS Exposure Time Calculators

ETC Release Notes Updated 12/07/2011

The Exposure Time Calculators (ETCs) are online tools that predict the count rates and S/N in various observing modes given specified source characteristics. STIS provides ETCs for three separate scenarios:

Spectroscopic Science Exposures

Use this ETC to calculate the count rates and S/N ratio for a simulated spectrum of ONE source in a STIS spectroscopic observation.

• STIS Spectroscopic ETC

Imaging Science Exposures

Use this ETC to calculate the count rates and S/N ratio for imaging observations of external targets.

• STIS Imaging ETC

Imaging Target Acquisition

Use this ETC to calculate exposure times for target acquisition exposure.

• STIS Target Acquisition ETC
• STIS Target Acquisition Simulator (Old CGI version)

Previous Calculations

Use this ETC to recall previous calculations, using the ETC ID number. Note all STIS ETC ID numbers must include the preceding "STIS" to recall a previous calculation.

• Recall Previous Calculations for Cycles after Cycle 18

Known Issues and Features