Before GPS, polar parties fixed their position the way you are learning to: an instrument, a home-made level surface,
a watch and a book of tables. What they wrote down, from their own books.
Roald Amundsen
AntarcticSouth Pole · Dec 1911
Kit: Two sextants, three artificial horizons (two black-glass, one mercury), five watches.
- Steered by compass and sledge-meter; noon sights for latitude on the way, no longitude.
- Near the Pole: a midnight sight turned out wrong. Amundsen: a single sight is “unreliable and valueless”.
- Three skiers boxed in the area (diagram above) while two men took sun sights every hour from 6 a.m. to 7 p.m.
- At “Polheim”: a snow pedestal for the horizon, a second one to rest the sextant on; sights every hour for 24 hours, in two six-hour watches.
TimeAbout 3 days at the Pole; the 24-hour series alone took a full day and night.
ResultProbably 2–3 km from the Pole (Alexander 1912; Hinks 1944; Orheim 2011).
Note: Which horizon they used at the Pole is uncertain: a glass one was left in the tent; a photo caption shows mercury.
Sources: Amundsen, The South Pole · Orheim 2011, Polar Record · Lantz 2022, Polar Record
Robert F. Scott & Henry Bowers
AntarcticSouth Pole · Jan 1912
Kit: A theodolite: it measures altitude against its own spirit level, so no horizon was needed.
- Bowers was the only observer, and he also worked out longitude as they went.
- Sights at lunch and in the evening in a hard wind at −29 °C.
- He worked out the results in his sleeping bag “long after the others are asleep”.
TimeAbout a day of sights and marching at the Pole.
ResultFirst 3.5 miles from the Pole; after walking on, “½ to ¾ of a mile”.
Sources: Scott's Last Expedition, vol. I · Scott's diary, 17 Jan 1912 (SPRI)
Kit: A 2 lb theodolite, a pocket sextant, a glass artificial horizon (10 oz), watches, a Nautical Almanac.
- Latitude, longitude (time against their watches) and compass variation, observed on the drift ice.
- Worked out in the sleeping bag: logarithms with “tender, frost-bitten fingers”.
- Turned back at 86°14′ N, the farthest north then reached.
- Then they let both watches run down. Nansen rebuilt the time from a sight plus a guessed longitude.
TimeOne reduction could take most of a day.
ResultLatitudes were good. The watches were 26 minutes out: longitude wrong by about 6½°, which they only found at Jackson's camp in June 1896.
Note: Lesson for you: time is longitude. Check your watch against GPS time every night.
Sources: Nansen, Farthest North, vol. II
Kit: A sextant and a mercury horizon in a wooden trough under a glass roof, in a wooden box.
- If windy: a semicircle of snow blocks, two tiers high, open to the sun.
- Bed the box firmly in packed snow; lay a skin over the snow against glare and melting.
- Warm the mercury in the igloo, then pour it into the trough. Roof on, long side towards the sun.
- Lie flat on a skin, elbows in the snow, notebook and pencil under the right hand.
Time13 single sun altitudes over about a day at “Camp Jesup”, at −11 to −30 °F (−24 to −34 °C).
ResultClaimed within about 10 miles. Disputed ever since.
Note: No longitude sights after leaving land and no trained navigator in the last stretch. A 1989 review said within 5 miles; Wally Herbert and others say he fell short.
Sources: Peary, The North Pole · US Capitol: Peary's calculations
Kit: A 3-inch theodolite, a sextant and artificial horizon, three chronometer watches, two volumes of Hints to Travellers.
- Noon meridian altitudes for latitude on the way: “A meridian altitude gave us latitude 87° 22′”.
- The last dash carried only a flag, camera, glasses and compass.
TimeOne noon sight per day, when the weather allowed.
Result88°23′ S, but that was by dead reckoning, not an observation.
Sources: Shackleton, The Heart of the Antarctic
Kit: A sextant with an artificial horizon, on sea ice.
- “The artificial horizon set up”, then a noon meridian altitude.
TimeOne noon sight.
Result83°20′26″ N, the farthest north at the time.
Note: At the winter observatory, breath froze “on the arcs and verniers … and on the glasses”.
Sources: Markham, The Great Frozen Sea
Kit: A 10-inch sextant, a 14-inch octant, a chronometer, and three artificial horizons.
- A water horizon, trusted most, but too dim for the Moon and stars.
- A glass plate on half a wooden ball, levelled with a spirit level on three screws.
- A spare index mirror on a board, used for stars.
TimeThe chronometer was wound every noon; it lost 15.5 seconds a day, which they allowed for.
ResultLatitude and longitude observations along the whole route, used for their maps.
Note: The closest match to what you do: a liquid horizon, on land, at night.
Sources: Lewis & Clark journals, 22 Jul 1804
Mercury
The standard. It freezes at −38.8 °C: in 1826 Franklin's men froze it into a bullet and fired it at a door. Peary warmed his in the igloo and observed only when it was not much colder than −40.
Black glass
A levelled plate: light, but only as good as its bubble and its flatness. Amundsen, Nansen and Cook all carried one.
Treacle, oil, water
The Royal Geographical Society's Hints to Travellers (1906) suggests “treacle or other viscous liquid”. No polar sledging account found so far describes actually using one.
No horizon at all
A theodolite has its own spirit level (Scott, Nansen, Shackleton). A bubble sextant does the same (Byrd, 1926).
Problems they wrote about: breath freezing on mirrors and scales, brass screws working loose in the cold, frozen spirit compasses,
refraction tables that stopped at −10 °F, and frost-bitten fingers doing arithmetic.