In Phase II, proposers of SBC observations are required to check their targets and fields in detail for excessively bright sources, by the Phase II deadline. The relevant policies and procedures are described here. See also the ACS Instrument Handbook, Section 7.2, including Tables 7.3 and 7.4, which give the applicable countrate and V-magnitude screening limits, respectively. STScI has developed bright object tools (BOT) to conduct detailed field checking prior to SBC program implementation. These tools are based on automated analysis of the fields by means of data from the second Guide Star Catalogue (GSC2) and displays of the Digital Sky Survey (DSS). GSC2 provides two magnitudes (photographic J and F), hence one color, for most fields down to about 22nd mag, which, combined with conservative spectral-type vs. color relationships, supports determinations derived from the Exposure Time Calculator (ETC) of safety or otherwise for individual objects. In the best cases, these procedures allow expeditious safety clearing, but in some cases the GSC2 is inadequate because of crowding or absence of one of the filters, for instance. Then supplementary information must be provided by the proposers to support the bright object protection (BOP) process. The target should always be checked directly in the ETC with the more detailed information generally available for it, rather than relying on its field report data. STScI will check all targets and fields before any SBC observations are cleared. However, by policy GOs must provide screened, safe targets for SBC programs, and supplementary data as needed to verify target and field safety. The APT/BOT, including an Aladin interface, makes the BOP procedures accessible for GO use. Extensive help files and training movies are available. While the procedures may appear complex on first exposure, their convenience and straightforward application rapidly become apparent. All SBC proposers must conduct BOP reviews of their targets and fields in conjunction with their Phase II preparations. Thus, they will become aware of any problems earlier, such as the need for supplementary data, which may otherwise entail lengthy implementation delays following the Phase II deadline. (An exception is moving target fields, which must be cleared after the scheduling windows have been established.) To assist with these procedures, a Contact Scientist (CS) who is an SBC/BOP specialist will be assigned to each SBC program, to interact with the GO as necessary and requested during the Phase II preparations, and through program execution. Briefly, for a single default SBC pointing with unconstrained orientation, a field of 70 arcseconds in diameter must be cleared. The APT/BOT automatically reports on all GSC2 stars within that field. If any displacements from the default pointing (e.g., POS TARGs, patterns, or mosaics) are specified, the field to be cleared increases commensurately. POS TARG vectors and the enlarged, rotated field circles are conveniently displayed in APT/Aladin. No unsafe or unknown star may lie within 5 arcseconds of the detector edge at any orientation. Conversely, POS TARGs and orientation restrictions may be introduced to avoid bright objects in the fields (but beware of moving back to the bad rows or the edges of the detector). In case a single guide-star implementation becomes necessary, the field to be cleared increases to 140 arcseconds in diameter, but usually that will not become known until scheduling is attempted after the Phase II deadline. An SBC GO must send his/her CS, by the Phase II deadline, ETC calculations for each discrete target, and reports on any unsafe or unknown stars from APT/BOT for each field, either showing that the observations are in fact safe, or documenting any unresolved issues. In the latter case, including inadequacy of BOT/GSC2 to clear the observations, other photometric or spectroscopic data sources must be sought by the GO to clear the fields. Many of these are available directly through the APT/Aladin interface (although automatic BOP calculations are currently available only with GSC2), including the STScI Multimission Archive (MAST), which contains the IUE and GALEX data in addition to the HST data. An existing UV spectrogram of the target or class may be imported directly into the ETC; IUE data must be low resolution, large aperture for BOP. If model spectra are used, the original Kurucz (not Castelli & Kurucz) set should be used for early-type stars. None of the provided models is adequate for late-type stars, since they lack chromospheric emission lines; actual UV data must be used for them. In worst cases, new groundbased data or HST CCD UV exposures may be required to clear the fields for BOP; in general, the latter must be covered by the existing Phase I time allocation. If a given star has only a V magnitude, it must be treated as an unreddened O5 star. (The older Kurucz O5 model with higher Teff in the ETC should be used for BOP purposes.) If one color is available, it may be processed as a reddened O5 (which will always have a greater UV flux than an unreddened star of the same color). If two colors are available, then the actual (main-sequence) spectral type and reddening can be estimated separately. The APT/BOT now automatically clears faint stars with only one GSC2 magnitude available, on the unreddened O5 assumption, greatly reducing the number of stars reported as "unknown". Any remaining unknowns must be cleared explicitly. In some cases, the 2MASS JHK may be the only photometry available for an otherwise "unknown" star. It is possible to estimate V and E(B-V) from those data on the assumption of a reddened O5 star, and thus determine its countrates in the ETC. F. Martins & B. Plez, A&A, 457, 637 (2006), derive (J-H)_0 = -0.11 for all O stars; and (V-J)_0 = -0.67, (V-H)_0 = -0.79 for early O types. (The K band should be avoided for BOP because of various instrumental and astrophysical complications.) M.S. Bessell & J.M. Brett, PASP, 100, 1134 (1988), Appendix B, give relationships between the NIR reddenings and E(B-V). These data determine the necessary parameters. Note that the ETC also supports direct entry of observed J, H magnitudes with E(B-V). It is not expected that all such issues will be resolved by the Phase II deadline, but they should at least be identified and have planned resolutions by then. Another possible resolution is a change to a less sensitive SBC configuration. Any SBC targets or fields that cannot be demonstrated to be safe to a reasonable level of certainty in the judgement of the CS will not be observed. It is possible that equivalent alternative targets may be approved upon request in that case; but any observations that trigger the onboard safety mechanisms will not be replaced. A related issue is SBC pointing specification changes after the targets and fields have been cleared by the STScI BOP review. Any such changes must be approved by the ACS Team on the basis of a specific scientific justification and a new BOP review by the GO, which may be submitted via the CS if absolutely necessary. However, in general such requests should be avoided by ensuring that submitted SBC specifications are final, to prevent a need for multiple BOP reviews. GOs planning SBC observations of unpredictably variable targets, such as cataclysmic variables, are reminded of the special BOP procedures in effect for them, which are detailed in ACS ISR 06-04.