For general information on the following tools, please see the Help file.
Please see ETC accuracy for general information. CTE or Charge Transfer Efficiency effects are important and are not included in these calculations; for discussion of CTE effects see the Quick Start Guide.
Estimate WFPC2 Exposure Time/SNR for:
Point sources.
Extended sources.
Point sources + stellar background.
Extended sources + stellar background.
The WFPC2 Filter Throughput directory contains throughput tables for all WFPC2 filters.
ETC - News: On 2/1/2007 we changed the default data analysis method in the point source ETCs from "Optimal PSF Weighting" to a 2.0 pixel radius circular aperture. Optimal PSF weighting can still be selected by clicking its button.
Known Bugs in the ETC.
Please send comments about this page to biretta@stsci.edu.