On 28 February your 1850 zone time DR position is LAT 27°49.0'N, LONG 159°24.0'W. Considering their magnitude, azimuth, and altitude, which group includes the three stars best suited for a fix at star time?
• Star selection for evening/morning fix: altitude between about 30°–70°, stars spread well apart in azimuth (ideally 60°–120° between them) • Date and DR position effect: observer’s latitude (about 28°N) and time of year (late February) control which stars are high enough and not too low • Understanding star brightness and identification: focus on major navigation stars and their approximate sky regions (north, south, east, west)
• From 27°49′N, which stars in each group are likely to be very low (near the horizon) or very high (near the zenith) and therefore poor for a fix? • Looking at each triple, which set gives you three stars that are well spread in direction around the horizon instead of all clustered to one side of the sky? • Which group has stars that are all strong, commonly used navigational stars, with reasonable altitudes at typical evening star times in late winter in the North Pacific?
• For each choice, mentally place each star as generally north/south/east/west of you at that date and latitude; avoid groups that concentrate in one quadrant • Eliminate any set where a star would likely have altitude less than ~15° (too low) or greater than ~75° (too high) at star time for your latitude • Prefer the group that gives an even spread of azimuths (e.g., roughly separated around the horizon), not three stars along nearly the same bearing
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