Celestial navigation by day

[Rockin Robbins]

You can forget about the sky being anywhere near good enough in SH4 to do ANY celestial navigation from it. The only celestial navigation that can be done comes from knowing the position of the sub, putting those figures into a planetarium program and then doing the celestial navigation from there. SH4 was never meant to be a night sky simulation and it is not. It has a sky. That sky, especially solar system positions, is not accurate for date and time.

Typically, what is done with the Sun is meridian transit times. You have an accurate chronometer set for GMT. You get the time the sun passes its highest point. That is noon. The difference between GMT and your transit time is your longitude. This is not particularly accurate due to the size of the sun and the interpolation between precisely timed observations necessary to determine transit time. But it will get you in the same zip code.