The north-south shift could be used to avoid a good fraction of the problems created by the contaminated zones if objects north of 0° declination were always observed from KPNO while objects south of 0° were observed from CTIO. However, in order to avoid the contaminated zones completely, these zones for the respective observatories must not overlap in declination. In Figures 3A and 3C the zones for CTIO and KPNO do overlap a small amount, creating a band between declinations -2° and +2° in which faint object astronomy would not be feasible from either observatory. This 4° band represents the minimum effect, reflecting the assumptions made in the Briefing Document. However, by doubling the apparent brightness of the individual satellites (Figures 3B and 3D), this band is increased in width to 12°, more than one-tenth of the visible sky. This doubling would increase the width of the zone in which SPS is a severe hindrance to more than 40°, or approximately one-third of the sky. This condition dramatically illustrates a major concern of the working group-- that seemingly small deviations from the Briefing Document description of the SPS will result in a considerably amplified effect on optical astronomy. A final consequence of the positioning of the satellites in geostationary orbits is illustrated in Figure 1 of the Briefing Document. This figure shows the apparent position of the satellites as they would appear from several observatories. The working group noted that if the satellites were positioned as described in the Briefing Document, Mauna Kea Observatory (MKO) in Hawaii would be far less affected by the SPS. The possibility that the Pacific Ocean area could be kept free of power satellites was perceived as an important possibility. This, however, would make Hawaii ineligible for power from the SPS. EFFECTS ON OPTICAL ASTRONOMY The primary effect of the SPS on optical astronomy is to contaminate a large region of the sky to the extent that the study of astronomical objects currently at the limit of detection would be impossible within that zone. The size of the region is extremely sensitive to the properties of the SPS and the meteorological conditions at specific observatories. The impact is greatest for those observatories at longitudes nearest the center of the satellite
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