PM Sun Sight / Running Fix

Afternoon sun sight, then Sun-Run Fix — FairWinds advances your AM LOP by the boat track and crosses it with the PM LOP.

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When

Two Daily Schedule steps share this afternoon window:

After the noon window → sunset. Best practice in the app: 2–4 hours after the AM sight, with ≥60° of azimuth change between the two. The engine accepts pairs from about 30 minutes to 12 hours apart on the same day.

In FairWinds (Guided)

1. Take the PM sight

1. Sun tab → Sextant → shoot the sun → Save
2. Confirm a PM badge on the new Sun Sights row

2. Compute the Sun-Run Fix

1. Still on the Sun tab, check exactly two sights (your AM and PM)
2. The Sun Worksheet shows Running Fix with Course / Speed / Elapsed / Run from your boat track between the two sight times
3. Tap Compute Running Fix
4. Optional: Plot Running Fix
5. Tap Save to Log

Saved as a Sun run fix in Positions.

FairWinds does not advance a noon latitude line against a single PM LOP for this step. The product path is sun-run-sun: AM LOP advanced by the logged run, crossed with the PM LOP.

How the run is calculated

1. Each sight stores UTC plus the DR/position used at capture
2. Running Fix builds the run vector between those two attached positions (distance + course)
3. Displayed speed is distance / elapsed for that interval

Changing a DR later does not rewrite DR values already stored on older sights — keep your Positions / AP workflow consistent between the two sights.

Why it matters

This is your main afternoon full fix when you are working the sun. It confirms the morning work and gives you a fresh position before sunset and evening twilight.

Expert mode

Auto Compute Running Fix is hidden. Reduce both sights externally, advance the AM line by your run, then Fixes tab → Enter Fix → Running Fix.

Required — afternoon position and DR reset for the evening.