Intermediate settings have roughly a factor of two less accuracy. Assumes star is well-centered in slit. See the HST Data Handbook for a more complete description of the impact of centering on accuracies. See the HST Data Handbook for a fuller description of the impact of slit width on photometric accuracy. All accuracies refer to prime wavelength settings and directly calibrated special secondary settings.
Intermediate settings have roughly a factor of two less accuracy.
Assumes star is well-centered in slit. See the HST Data Handbook for a more complete description of the impact of centering on accuracies. Assumes use of a wide photometric slit. See the HST Data Handbook for a fuller description of the impact of slit width on photometric accuracy. For 0.2x0.2 arcsecond slit.