Sun navigation challenges

Enjoy exploring this page sun navigation challenges BUT ONLY AFTER COMPLETING the foundational La Rochelle exercise.

The main goal of these exercises is to calculate and understand how to calculate the line of position with the sun in daytime.

“La Rochelle” is the first in a series of eight identical exercises, each named after a major city in the world near the simulated sextant observations.

This page focuses on the Tokyo exercise and can find the others on the Celestial Course page.

While the La Rochelle exercise is for free, the answers for the remaining exercises can be bought in the store.

Sun navigation challenges:

Keep in mind that when the Latitude aligns with the sun’s Declination, a situation common in the tropics, the St. Marcq method becomes inapplicable. (see below: design number 5)

Sun navigation challenges, image difference between sun's declination and latitude
Some possible differences between the sun’s declination and the latitude.

Firstly, on this page Tokyo you will find all the sextant sun sight observations required after taking a sun sight at sea off the coast of Tokyo.

Tokyo Tower(2016) author: Kakidai

Sun navigation challenges:

Sun navigation challenges, image calculator

print/download PDF worksheet or copy by hand

Sun navigation challenges, worksheet with red entries

First part of the sheet of the sun sight observations

Firstly, start manually completing the red entries on this page.


sun navigation challenges Tokyo:

Time UT and Date

Sun navigation challenges, image watch

DAY = Sunday; DATE = 06/03/2022; UT Time = 20:16:54


sextant height (Hs)

Sun navigation challenges, image sextant height

lower limb


index error

Sun navigation challenges, image sextant index error

Non adjustable error

Sun navigation challenges, image inspection certificate

Sun navigation challenges:

`eye height

Sun navigation challenges, image eye height

Dead reckoning position:

Latitude (L) :

33°21′ North

Longitude (G) :

150° 18′ West


daily page

nautical almanac

Sun navigation challenges, image daily page nautical almanac

Also this daily page has been downloaded on the nauticalalmanac.it website with the kind permission of its author Capt. Roberto Iori




Malmö, Sweden Maria Eklind

sun navigation challenges: the sea east of Tokyo


The sea east of Tokyo is the Pacific Ocean, known for its vastness and significance in global maritime trade. Overall, it encompasses the Kuroshio Current, a powerful warm current that influences the region’s climate and supports diverse marine life.

Furthermore, the Pacific Ocean has historical importance, having witnessed pivotal events like World War II’s Pacific Theater. Also, Tokyo Bay, situated along the coast, serves as a vital port and plays a crucial role in Japan’s economic activities.

The sea also hosts various recreational activities, such as boating and fishing. While providing valuable resources, the Pacific Ocean faces environmental challenges, including pollution and overfishing.

Overall, the sea east of Tokyo is a dynamic and multifaceted ecosystem, playing a central role in the cultural, economic, and ecological fabric of the region.