Computing Cook & Peary at the Pole, c. 2000

Does modern technology and computer science have the ability to determine where explorers were 90 years ago based on their diary observations and field notes?  A weather person in the high Arctic and a New Zealand explorer who led a party to the pole in 1996 suggest that data exists to establish such a case.

Where were they on

April 21, 1908 (Cook)?

April 29, 1909 (Peary)?

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Historical allegations at being close to the North Pole are provable.

by Wayne Davidson, Upper Air Station Operator Resolute Bay, Nunavut, Canada


Many journals, books and reviews have covered the famous Peary and Cook debate, the rivalry dates back to the first decade of the 20th century.   Dr. F.A. Cook arrived at the pole April 21, 1908; Peary claimed the Pole on April 6 the following year.  The only way to validate either explorer claims is by analyzing results from the sole instrument they have used to get them to the Northernmost point on earth, the sextant.

Expert analysis by Wally Herbert, the National Geographic Society and others dealt with intangibles, unverifiable facts, such as ice movements, mysterious Islands, picture captions from publications and testimony from Inuit (no longer called Eskimos).  Their analysis, however well informed, has not resolved the issues, but rather polarized the subject almost to the point of no return.

for explorers, pack ice of the Arctic Ocean is the playing field.  It is different every month, and the ice is constantly moving, crushed, displaced and piled up.  Thicker old ice pans are like a big gorilla crushing the young ice to pieces every time it moves, raising pressure ridges as high as ten meters.   It is unwise to estimate ice movement before the advent of buoys and ice stations (1937).  Peary and Cook were not on the ice long enough to make certain pronouncements on Polar ice movements.

Ice moves according to force vectors, they are sea currents, tides, winds and momentum.  Ice easily moves against underlying sea currents for weeks.  Naturally, ice moves according to average circulation patterns just as well.  but wind vectors frequently overwhelm all others from about April to November.  Estimating where Peary was, based on average ice movements is not a good idea.

The playing field is never the same.  Comparing one expedition to the next is not even advisable during the same season.  for instance, many year 2000 explorer skiers have achieved the Pole without support, all had similar equipment, but none achieved their goal with comparable results; the Swedish team established a world record of 41 days to the Pole from Ward Hunt, while royal Marines and a soloist from Iceland took many more days even though they started at the same location.   The Swedes found many North-South frozen leads and this increased their speed enormously, while the Marines and Icelander worked much harder.

High Arctic weather rules the Polar landscape.  With time, winds carve mountains just as easily as sea ice in a few hours.  Temperatures dictate the seasons. The occasional tourist may find that there are two seasons, the long day and the long night periods.  However, Inuits know more than a dozen seasons, all noticed by animal and astronomical events.  Migrating birds arrive according to climatic conditions, they are still part of the Inuit living dynamic calendar.  Very long-range weather prediction usually are wrong for the future and likewise for the past.   Some arctic experts tend to over emphasize their experience and mistakenly project it to another period.  Dominant winds and temperatures vary quite a lot during just a few years.

Polar ice cap explorers eventually learn that cold weather is their friend.  Leads open all the time.  However long-day or "spring" weather is usually treacherous with rotten ice and leads having vast expanses of open water.  More modern expeditions fail because of water -- more so than any other reason.  Peary discovered this the hard way in his 1906 first attempt to the Pole.  It is mainly for this reason that his final attempt was made earlier.

The North Pole is a fictitious appendage, placed in the middle of the Earth vertically.  It is easily recognizable once during the summer solstice where the sun appears to revolve around the sky for 24 hours while maintaining the same elevation.  The North Pole has no Meridian lines, its latitude is 90 degrees North.  Today the pole is about 50 meters wide, the limit of most GPS Units.   Surprisingly, a properly calibrated sextant could achieve a high degree of precision, not as high as the GPS, but one can easily find a location within two miles.   This should have been the standard for Cook and Peary, the Pole was wider in 1908-09.

The sextant had limitations, known perhaps by most navigators.  It was a common practice to use the sextant at noon, when then sun was at its highest point in the sky.  This reduced possible errors caused by refraction, the bending of light passing through air, however, near the Pole the sun is never too high.  Peary relied o his navigation skills, and most certainly on the certain knowledge that Inuit were just as good as him, if not better.  Utah, Iquinuah, Siiglu and Uqlah were part of a navigation high technology heritage, they were capable of finding any direction within their territory.  Even today, Inuit find their way home through the most horrible blizzards.

Peary never bothered finding the 70th Meridian, as he was traveling by "shadows a noon" from Cape Columbia.  It is doubtful, that he kept that Meridian.  Even modern GPS equipped, year 2000 explorers don't travel by a straight geographical North-South lines.  It is doubtful that Peary's Inuit guides understood the abstract concept of cartography mathematics.  Not even then would they have followed the 70th.  Peary himself didn't have sunshine all the way.  He wasn't on the 70th, but he might have been close to it because of Inuit legendary skills, in this case, recognizing the location of Cape Columbia from afar.

Peary's North Pole measurements coincide exactly with a standard old method calculation of refraction, which is no longer applicable.  He could not have measured the sun at that elevation.  It is not an instrument mistake within the margin of error found with sextants, since other measurements at the Pole show the same flaw.  No sextant readings were inscribed in his logbook while he was at the Pole; the pages were left blank.  Instead historically famous paper inserts were placed within.  They are what they appear to be -- inserts placed there sometime after he claimed the Pole.  However, they can't be measurements, rather a contemporary state of the art attempt to fake a sextant observation at the Pole.   Peary probably was somewhere around the Pole -- within 200 miles.  An extremely sophisticated multi-disciplined team can estimate his most likely locations, especially taking into account sea bottom soundings combined with new sextant corrections.   It is quite possible he overshot the 0 to 180 degree West meridian line, and ended up somewhere on the Russian quadrant near the Pole.

In retrospect, Peary would have been better off to report that he couldn't locate the Pole on account of a strange phenomena.  Having doe so, he would have been credited for having found a new navigation flaw, and eventually credited for being very near the Pole, since this refraction anomaly can easily be found especially there.

Dr. Cook was around the Pole on April 21, 1908, a much better time for a sextant.  Doctor Cook's measurements do not show any of Peary's impossibilities.  Dr. Cook's raw observations place him always at equal or higher sun elevations, which is slightly South to where he thought he was.  This means that there were no apparent deceptions in his presentations, which were released shortly after he arrived from the Pole (unlike Peary's 1988 release).

Dr. Cook may have been a victim of bad publishing as well, especially with his famous My Attainment of the Pole photo captions.   Publisher do make caption or editorial mistakes.  Saying otherwise would acknowledge thousands of Internet web sites, including one from NASA, showing the tilt of the Earth axis at 23.5 degrees.  Is it?

No, it is 23.43 degrees.

From Frederick A. Cook, My Attainment of the Pole
1913 edition, page 309.


Can computer refraction data substantiate
the observations of Cook & Peary in 1908 - 09?


Newer Polar refraction tables can pin point with higher accuracy Cook and Peary's locations; they can also tell if they were at the location they claimed. Differential refraction is a term used to explain the strange appearance of the sun one might have seen before sunset and after sunrise. The image of the lower part of the sun disk appears flatter than the upper part, this comes about by the lower part of the disk pushing itself into the upper part. Refraction is higher on the lower rim and less above.

Peary's differential refraction was about 10 seconds of arc, which is roughly five times less than expected by a new but conservative refraction table. Frequent Arctic observations show the sun appearing awfully distorted and compressed. The lower rim of the sun appears quite flat during early spring. Differential refraction in the Arctic seems to be much greater than previously thought, although a lot of field work is needed to prove mathematical models. Confirming a refraction model will tell whether sextant observations were back calculated.

The sextant uses the sun disk in order to determine latitude and longitude.

After the long night the sun rises slowly from below to shed twilight at the Pole. At the spring equinox, March 21, the sun spirals continuously upwards around the Pole until June 21. During the Polar Spring, day and night depends on where the sun is with respect to the rotating Earth. When the sun is shinning on America at noon, it is at its lowest elevation on the other side of the Pole until darkness is reached near the Arctic Circle on the Russian side. Night prevails below that circle. Twelve hours later, when the sun bristles over Russia, the opposite occurs, the lowest sun elevation is found near the North American Arctic Circle.

The sun's elevation is a measurement of its height in degree angles. For the purpose of this narrative we will be dealing with angles not much greater than six degrees, which is quite low in the sky.


Peary claimed being at or near the Pole on three different occasions, and he wrote his observations on paper inserts which were tucked in his navigation log book. The three inserts are dated and timed: April 6 at 1650 GMT (Greenwich Mean Time), April 7 1040 GMT and April 7 at 1640 GMT. All of his observations are, to put it mildly, questionable.


Peary allegedly arrived at the Pole on April 6. His insert for that day was checked with computer programs, and yes it confirms that Peary calculated exactly his location, with no variances at all, he was at:

89 57 11 North 70 West

His sun elevation is nearly perfect provided that his chronometer time was not corrected. His refraction correction is assumed to be exact. This latitude gives a location within 7.2 seconds of arc (600 feet). The wrong time gives the right sun elevation exceeding the precision limits of his sextant.

Unfortunately, this kind of accuracy is not possible without a GPS unit, refraction correction was of course incorrect by about 2 minutes of arc. Correct chronometer time brings Peary about 1000 feet away. The computer and Peary should not agree, especially since the sun elevation measured should not correspond with the wrong time. The only way to achieve this so called measurement is by back calculating from a navigation almanac while using the wrong time.

APRIL 7 1240 AM:

Just 12 hours prior Peary claimed the Pole at Camp Jesup, he decided to move:

"He loaded a sledge with instruments, his artificial horizon paraphernalia, a tin of pemmican and a few skins, and with Egingwah and Seeglo journeyed north for about 10 miles to make a midnight reading. This observation showed him to be beyond the Pole."   Peary at the Pole, p. 41

On April 7, precisely at 0430 GMT, Peary made an observation which defies logic. Peary wrote Apr7 12 40 AM, this is 0430 GMT (his clock is 10 minutes fast). Peary calculated his location as:

89 49 45 North

Right after achieving the Pole within 3 miles on April 6, Peary makes a ten mile journey Northwards! Peary's raw sun elevation for this April 7 observation is:

6 53 35 degrees

This sun elevation does not exist on the 70th Meridian or anywhere on the North American Polar sector, as it is night in America. However identical elevation exists at many points of various distances from the Pole on the Russian side of the Pole. This insert does not say what longitude he was on.

APRIL 7 0640 AM:

"He returned to Camp Jesup and at 6:00 AM, April 7, took another series of observations at right angles to those already made there. From these he calculated that the camp was within 4 or 5 miles from the Pole." Peary at the Pole, p. 41

There is something else which is very obvious, and of course invisible. The next alleged observation on April 7 is at 1030 GMT (0630 AM), Peary measured the sun having an elevation of:

6 degrees 44 minutes and 44 seconds

His own handwritten calculations gave him this location:

90 degrees 4 minutes and 26 seconds of latitude

This location doesn't exist on the Earth. To make it simple, the North Pole is at 90 degrees latitude North, the rest of the world is found at latitudes below 90. The only way to achieve this calculation is by not knowing which longitude he was on.

The Foundation for the Promotion of the Art of Navigation, which did the 1989 report confirming Peary's presence at the Pole, did not dwell too much on this measurement for a good reason: it is virtually not provable and highly impracticable.

Peary's 6 degrees 44 minutes and 44 seconds sun elevation on April 7, 1040 GMT, exists at many points of longitude, not uniquely around the Pole. At the Pole at that time (note 1040 GMT is very early in the morning) the sun elevation is 6 degrees 49 minutes and 48 seconds, 5 minutes higher than Peary's elevation. Further South towards Europe the sun elevation increases.

Using two possible scenarios:

  1. the inserts are authentic measurements, Peary didn't know his longitudes, therefore he was truly lost
  2. he faked North Pole measurements, suggesting a clever but flawed manipulation by Peary. Either way the Pole can not be found by this data.

To counter this the Foundation report finds the missing Longitude to the Southwest, namely at:

89 55 22.24 North 137 West of Greenwich

This location approximately coincides with the stated sun elevation. However, the Foundation gave no reasoning why Peary was moved to the 137th, aside from a tedious mathematical display attempting to determine the exact location of Camp Jesup. By changing Peary's longitude, the Foundation admitted that he was not traveling on the 70th Meridian after all, but they chose the closest possible locations having the greatest proximity to the Pole in agreement with Peary's sun elevations. The report bias in favor of Peary sticks out like an iceberg at this point.

Not taking Peary's notes literally casts a tremendous cloud over any evidence he provided. Likewise the famous April 7, 1040 GMT, sun elevation can be found at any chosen longitude:

Possible location of sun having elevation of 6 44 44:

Longitude Latitude Distance from Pole
Nautical Miles
68 W 85 59 N 241.0
70 W 88 20 N 100.0
75 W 89 23 N 37.0
80 W 89 36 N 24.0
110 W 89 52 N 8.0
140 W 89 54.5 N 5.5
170 W 89 54.5 N 5.5
150 E 89 51 N 9.0
120 E 89 18 N 42.0

All locations are valid provided that Peary's longitude is forgotten. But if one disregards Peary's steady 70th, he could have been anywhere between 5 to 200 miles from the Pole. 


Peary's closest observation to the Pole was made at the same time as all other observations while he was on his 70th West Northward track. The 1240 PM time is crucial, it is the time for Local Apparent Noon on the 70th Meridian. This insert shows a latitude:

89 58 37 North

This position can be accurately calculated despite Peary's small declination error, he really claimed Camp Jesup to be at:

89 58 26 North and 70 West at 1240 PM (1640 GMT)

According to this data, Peary was precise within an incredible 3.6 seconds of arc (300 feet), corrected time brings him a half a mile away.

1240 PM is of course off by 10 minutes. The erroneous time gives once again the precise location. Making other attempts to place Peary elsewhere is not necessary, since many other longitude locations will correspond to identical sun elevations at the same time. This 1240 PM insert is unique, it is not subject to interpretation, Peary himself attested to being on 70 West. This insert looks a lot like a back calculation.


Second guessing where Peary was, as in the Foundation Report, completely undermines Peary's credibility. Navigation logs are the greatest element of value for any explorer. They must be taken literally otherwise there is nothing to prove. A sextant reading without longitude has no meaning.

Any 20th-century explorer being at the North Pole should have had suspicions about the accuracy of sextant measurements at low sun angles. Dr. Cook very accurately stated doubts about his exact position:

"The exact altitude of the sun at noon of April 22, 1908, on the pole, was 12 9' 16", but owing to ice-drift the impossibility of accurate time and unknown error by refraction, no such pinpoint accuracy can be recorded. At each hour the sun, circling about the horizon, casts a shadow of uniform length." My Attainment of the Pole, p. 309

Dr. Cook doubted refraction corrections from his almanac, and they are indeed different. Having doubts about refraction could be achieved after a long journey to the Pole, where time of day can play havoc with preconceptions.

Two slightly different refraction computer models, show promise in reconfirming whether back calculations were done. Peary's measurements utterly contradict one model, almost comes close but fails another. Dr. Cook passes both models, however I have not reviewed any of his handwritten notes.

Ultimate proof for Cook and Peary may very well be small expeditions at the North Pole making sextant and GPS measurements simultaneously. But, for the time being, some of Peary's facts speak for themselves


The North Pole is an elusive modern concept. Although you can leave something on the very slow moving Antarctic South Pole ice, North Pole pack ice is much more mobile. Some say that it is impossible to prove whether Cook or Peary were at the Pole, as they didn't have a chance in leaving such proof. Evidence exists however that Cook and Peary had one unknown factor embedded in their observations which is better understood today.

Refraction is a physical phenomena of the bending of light through different transparent mediums. One can take a glass of water, put a pencil in it, and notice that it is no longer straight at the juncture of air and water. The sun disk goes through the same bending process. There are many different air layers in our atmosphere, each layer bends light not as much as water, but in essence the sun disk appears higher than it really is. This extends daylight at dawn and dusk everywhere on the Earth but much more at the poles.

Cook and Peary used a sextant, a portable telescope. This instrument can pinpoint the position of the sun with a high degree of precision. According to the Foundation for the Promotion of the Art of Navigation, Robert Peary's sextant could measure astral objects within 10 seconds of arc. Ten seconds translates to about 900 feet on the ground, once used properly, this instrument can locate the user within 900 feet. Today a Global Positioning System (GPS) instrument can locate the modern explorer within 50 meters (150 feet). 

Peary surely had a lot of surveying experience, and one must conclude that his Arctic measurements should come very near the limits imposed by his sextant. The claimed problem with reviewing Peary's North Pole inserts is that there was no way of checking if he was there. Herbert estimated that he was somewhere to the West of the Pole by about 150 miles. This number might have been inspired in part by the Earth's rotation speed of 900 miles an hour (at the equator), Peary's clock was off by 10 minutes in 10 minutes the Earth rotates 150 miles.

Wally Herbert's conclusion that Peary was taken West by ice drift is a bit contentious. Polar pack ice never moves in a consistent pattern during short time spans. But, Local Apparent Noon (upper transit) measurement of the sun disk position was the only way sextant measurements could have determined longitude.

Arctic refraction cause sun disks at lower elevations to be very distorted in winter, more so than sunset sunrises in warmer climates. The sun also appears much flatter and jagged, this is also caused by refraction. The sextant user will be somewhat compromised by other distortions as well such as ice crystal generated sun Pillars. The two top photos of the sun here illustrate this phenomenon.

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(above) Low sun early Spring in Resolute Bay, photo by Marko Riikonen.

(top right) First Sunrise North of Devon, video frame from "Hunting by Moonlight."

(right) Sunset somewhere in USA desert, photo by Tony Crow,

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NOTE:  Wayne Davidson submitted this professional paper as an individual with many years in High Arctic weather recording and research. The conclusions are his and in no way reflect those of the government of Canada or any of its agencies.


Court, Andrew. "Refractive Temperature," Compendium of Meteorology, 1951.

"Refraction in the Upper Atmosphere," Journal of the Franklin Institute, 1944.

Cook, Frederick A. My Attainment of the Pole, 1913 edition. New York: Mitchell Kennerley.

Frederick A. Cook Papers, Special Collections, Library of Congress. Field notes and computations, 19 Feb. 1908 to June 1908. Box 1, Reel 1; 30 March to 21 April, 1908. Box 21, Reel 22.

Peary at the Pole, Foundation for the Promotion of the Art of Navigation, 1989. Supplement Report, 10 pgs. and photos, 1990. Rockville, MD.

Peary, Robert E. The North Pole: Its Discovery in 1909, 1910. New York: Frederick A. Stokes Co.

U.S. Naval Observatory, Nautical Almanac Office. Air Almanac, 2000. Department of the Navy.

Editorial Note: Wayne Davidson is a weather observer for the Canadian Government. Since 1986, he has seen and consulted with most supported expeditions seeking to get to the geographical and magnetic North Pole on the North American side of the Arctic. He has learned from successful expedition members on their way home just as much as he has helped them with ice and weather information before departure. A graduate in several environmental science techniques, he maintains and runs important ozone research projects amongst other duties. Davidson has spent some time researching Sir John Franklin's ill fated 1845-48 expedition and studies actively atmospheric effects on star observations during the long High Arctic night. Both of these projects are posted on the Internet.


Copyright 2005 - The Frederick A. Cook Society