Meridian Nav

Meridian is a celestial navigation toolkit built at sea by a working deck

officer — fully offline, because mid-ocean is exactly where you need it.

SIGHT REDUCTION

Compute Hc, Zn and intercept for the Sun, Moon, four planets and 63

navigational stars. Enter your DR position, date/time and sextant altitude

— get your line of position.

COMPASS ERROR

Check gyro error by azimuth of any celestial body — the daily routine,

without the almanac and tables. Magnetic variation (WMM2025) is built in

for magnetic compass work.

STAR FINDER

A polar sky-dome view shows exactly which bodies are observable right now

from your position — plan your twilight sights before stepping out on

the bridge wing. Includes an azimuth-scatter view for picking the best

LOP geometry.

SUN / MOON

Rise, set, meridian passage and twilight times for any position and date.

MARINE CHART — FULLY OFFLINE

A custom offline vector chart with world time-zone (ZD) boundaries, DST

awareness, ports and waypoint routes. Import route files (.rtz / .rou)

straight from your ECDIS.

CLOCK PLAN

Generate the entire voyage's retard/advance schedule from your route —

including DST transitions and solar-zone departures. Reorder or edit the

changes, then export a clean calendar-style PDF or Excel notice, ready to

post on board.

UNIT CONVERTER

The conversions a navigator actually uses, in two taps.

ACCURACY & VALIDATION

Every body — Sun, Moon, planets and 63 navigational stars — is

cross-checked against JPL ephemeris data (the same source behind the

official Nautical Almanac) to arc-minute agreement. Star positions are

computed for the current date from the ESA Hipparcos catalogue. Sun

azimuth verified at sea against a ship's bridge calculator, and against

NOAA's solar calculator (0.000° difference).

MADE FOR

Deck officers who want a fast backup and sanity check, cadets and

officers studying celestial navigation, and anyone who believes a

navigator should still be able to find a ship without a satellite.

No account. No ads. No subscription. No internet required. One-time

purchase.

IMPORTANT

Meridian is a reference and training aid for celestial navigation. It is

not a certified navigation system and does not replace official nautical

publications, charts, or type-approved equipment.