🔍 Key Concepts

• Great-circle vs rhumb-line routes on a gnomonic chart (straight line = great circle) • How to determine the vertex latitude and longitude of a great-circle track between two positions • Relationship between solar declination (~23.5°N at June solstice) and visibility of the sun at both upper and lower transit (midnight sun)

💭 Think About

• Sketch or mentally visualize the great-circle track between 48°30'N, 125°00'W and 44°00'N, 161°00'E on a gnomonic chart: where is the highest latitude (vertex) relative to the Aleutians and to the arrival longitude? • Compare the highest latitude along your great-circle track with 53°N to see if the voyage passes through or near the stated military exercise area limits. • On 21 June, compare the maximum latitude of your track with the solar declination to decide if the sun would remain above the horizon for a full 24 hours (allowing both upper and lower transit to be visible).

✅ Before You Answer

• On a gnomonic chart, a straight line is a great-circle track; verify where that straight line crosses its highest latitude relative to 53°N and the Aleutian chain. • Use a standard vertex formula or plotting method to estimate if the vertex lies east or west of 161°E, then compare that to the wording of choice D. • For choice C, verify whether a latitude south of the Arctic Circle can observe both upper and lower transit of the sun on 21 June, given maximum solar declination of about 23.5°N.