[Munchausen]

Originally Posted by Frederf

I kinda have to complain that this "real nav" mod removed all the fine lines on the map for lat/long. This makes plotting your position, once calculated a real pain! I can still zoom in the same amount but now there's just blank ocean-blue paper there.

I didn't install the mod ... I just try to use sun and moon tables to determine when to surface and when to remain submerged. So I didn't realize this was part of the mod. In fact, the navigation chart should have more, not fewer, lines. I suspect the lines were removed to keep the player from "cheating" ... but it's hard to plot a D.R. or fix without latitude, longitude and tic (incremental marks along lat/long) lines.

The base time should be defined as the local time in the center of the time zone that your base is in. Basically if your base is in San Francisco your base time is GMT-8.

My base (point of departure) was Fremantle. Although sunset is later than I'd expect using the Tables, it comes nowhere near what I'd get if I used GMT +/- Fremantle's time zone.

Also using sun for latitude is not a simple 90-A = L arrangement but involves what day of the rear it is. Can anyone post details about that correction?

Thanks to the tilt of the earth, the sun doesn't "top out" at the same height above the horizon every day of the year. The sun reaches its highest point ("topping out") at what's called Transit ... and you can build a table for transit times in much the same way as you build a table for rise and set times.

Example:

It's the 4th of July and you want to find your latitude by taking a "noon" sun shot. Using the sextant, you track the sun and find that it tops out around 1204 local time, at 82 degrees ... to the north.

Transit tables show that, at latitude 30* north, the transit altitude of the sun is 83 degrees on the 4th ... but the sun is south of the observer. So ... you've got the wrong table.

At latitude 20* north, transit time is 87N (the sun is now north of the observer ... so, somewhere in between 30* north and 20* north, the sun was directly overhead ... if you were to sail quickly from 30* to 20* you'd watch the sun pass from south to overhead to north of you).

At latitude 10* north, transit time is 77N.

Interpolating, transit time for 82N would be latitude 15* north. This would be your present postion.