Campbell Cove, October 6, 1999.
On this day, due to the equation of time, the sun was approximately 16 minutes before the clock. Campbell Cove (123 W) is also 3 degrees west of the 120th meridian Pacific Standard Time 12:00, making it 12 minutes late by the clock. Therefore, the actual meridian transit of the sun (see watch in photo) occurred at about 12:56 PDT (11:56 PST).
Note the shadow of the foresight on the backsight, and the concentric halo of light surrounding the hole through the backsight.
It is this very excellent sighting method that makes the astrolabe a useful instrument--a 9" diameter astrolabe is, after all, a quadrant of only 4 1/2" semi diameter!
