Major revisions since Version 3.0 may be summarized as follows:
- Comparisons to FOC, STIS, and NICMOS.
- Observation Strategies: A new chapter (Ch. 7) has been added specifically to assist observers in preparing Phase II proposals.
- Exposure Time Estimation: Ch. 6 has been largely re-written. Signal-to-noise ratio equations for Poisson-limited, background-limited, and generalized cases are now included for point sources (both with PSF fitting and aperture photometry) and extended sources. The WWW on-line Exposure Time Calculator program is briefly described. A new Appendix gives representative SNR values for various exposures of stellar, power law, and emission line sources.
- CCD Performance: Material on dark current and CTE (charge transfer efficiency) has been updated.
- Calibration: Material on UV throughput, dark current calibration, flat fielding, and impact of focus variations on photometry has been updated. Cycle 6 calibration proposals are described.
- Other changes include addition of an index and an acronym list.