The Sun altitude correction tables are permanent: the Nautical Almanac reprints the same table every year.
Accordingly, on this page, you can download a Sun correction table, calculated by easysextant, for practical use at sea.
Sextant Corrections at a Glance:
Page 1: Hs to Ha – THEORY
Page 2: Hs to Ha – CALCULATION
Page 3: Ha to Ho – THEORY
Page 4: Ha to Ho – CALCULATION
Altitude correction tables. sun stars and planets
The star and planet corrections, as well as the lower limb correction, appear on this page in the Nautical Almanac.
The apparent altitude and dip correction table for the Sun from EasySextant.
Here is a table displaying apparent sun altitude corrections spanning from 16° to 90°. It includes corresponding adjustments for Dip, reflecting the impact of the observer’s elevation above sea level, within the range of 1 to 12 meters (3.3 to 39.4 feet).
Importantly, these corrections on my website are specifically calculated for the lower limb of the sun and do not account for the upper limb.
Sextant altitude correction tables
The Nautical Almanac provides the altitude correction tables for the sun. The tables cover all altitudes from 0° to 90° and the heights of the eye from 1 to 48 meters.
They provide corrections to apply to both the upper and lower limbs of the sun and are divided into two parts.
The first part explains the effects of refraction, semi-diameter, and parallax, while the second part offers the corrections for dip. Since the sun’s distance from the earth changes throughout the year, the tables account for the variation in semi-diameter.
Sextant altitude correction tables: two sections dependent on the time of the year.
The tables divide into two sections: one uses a semi-diameter of 16.15′ during the period October to March, and the other uses a semi-diameter of 15.9′ during April to September.
The observer enters the first table with the apparent altitude and the second table with the observer’s height of eye.
True altitude.
After applying all corrections, you obtain the true altitude: the angle above the celestial horizon as seen from the Earth’s center.