He made the first measurement of stellar parallax: 0. 3 arcsec for the binary star 61 Cygni.

Aberration should not be confused with stellar parallax, although it was an initially fruitless search for parallax that first led to its discovery.

61 Cygni is significant because Friedrich Wilhelm Bessel determined its parallax in 1838, the first star to have a known parallax.

With this work under his belt, Bessel was able to achieve the feat for which he is best remembered today: he is credited with being the first to use parallax in calculating the distance to a star.

Astronomers had believed for some time that parallax would provide the first accurate measurement of interstellar distances — in fact, in the 1830s there was a fierce competition between astronomers to be the first to measure a stellar parallax accurately.

According to Mohani Mohamed, the Arabian astronomer Alhazen ( 965 – 1037 ) made the first attempt at observing and measuring the Milky Way's parallax, and he thus " determined that because the Milky Way had no parallax, it was very remote from the Earth and did not belong to the atmosphere.

Among its results were determinations of the lunar and of the solar parallax ( Mars serving as an intermediary ), the first measurement of a South African arc of the meridian, and the observation of 10, 000 southern stars.

The first direct measurement of the distance to a star ( 61 Cygni at 11. 4 light-years ) was made in 1838 by Friedrich Bessel using the parallax technique.

It was one of the first stars whose distance was estimated through parallax measurements.

The first person to publish a star's parallax was Friedrich G. W. von Struve, when he announced a value of 0. 125 arcseconds ( 0. 125 ″) for Vega.

Thus most astronomers at the time, including Struve, credited Bessel with the first published parallax result.

Astronomers of the era expected that changes over time in the apparent separation and relative location of these stars would provide evidence for both the proper motion of stars and, by means of parallax shifts in their separation, for the distance of stars from the Earth ( a method first suggested by Galileo Galilei ).

* 11th century — Ibn al-Haytham ( Alhazen ), an Arabian astronomer, refutes Aristotle's theory on the Milky Way by making the first attempt at observing and measuring the Milky Way's parallax,

Their measurement of γ Virginis in 1718 was the first made of the components of a double star and was directed towards the determination of stellar parallax.

The first successful measurement of stellar parallax was made by Friedrich Bessel in 1838 for the star 61 Cygni using a Fraunhofer heliometer at Königsberg Observatory.

Measurement of annual parallax was the first reliable way to determine the distances to the closest stars.

The first successful measurements of stellar parallax were made by Friedrich Bessel in 1838 for the star 61 Cygni using a heliometer.

He was also the first to measure the parallax of Vega, although Friedrich Bessel had been the first to measure the parallax of a star ( 61 Cygni ).

Some conversions from one system of units to another need to be exact, without increasing or decreasing the precision of the first measurement.

: A further argument is that relativistic difficulties about establishing which measurement occurred first also undermine the idea that one observer is causing what the other is measuring.

This is totally spurious, since no matter who measured first the other will measure the opposite spin despite the fact that ( in theory ) the other has a 50 % ' probability ' ( 50: 50 chance ) of measuring the same spin, unless data about the first spin measurement has somehow passed faster than light ( of course TI gets around the light speed limit by having information travel backwards in time instead ).

This method of measurement is inherited from the method used for the first generation of CRT television, when picture tubes with circular faces were in common use.

It is one thing to say that physical measurement of the first particle's momentum affects uncertainty in its own position, but to say that measuring the first particle's momentum affects the uncertainty in the position of the other is another thing altogether.

His announcement of Sirius's " dark companion " in 1844 was the first correct claim of a previously unobserved companion by positional measurement, and eventually led to the discovery of Sirius B.

Among the first investigations of ferromagnetism are the pioneering works of Aleksandr Stoletov on measurement of the magnetic permeability of ferromagnetics, known as the Stoletov curve.

In 2008 it was suggested that the Pharos was the vertical yardstick used in the first precise measurement of the size of the earth.

The psychometrician L. L. Thurstone, founder and first president of the Psychometric Society in 1936, developed and applied a theoretical approach to measurement referred to as the law of comparative judgment, an approach that has close connections to the psychophysical theory of Ernst Heinrich Weber and Gustav Fechner.

Slipher first reports on his measurement in the inaugural volume of the Lowell Observatory Bulletin.

* One time, as the referees were spotting the ball before a measurement to determine if the Chiefs got a first down, Stram yelled to the officials, " You didn't mark it right!

Then they made an exact, or ' strong ', measurement of the first polarization to see whether it had been disturbed by the second measurement.

The results of the first test can be treated as a baseline or control measurement ; all subsequent tests can then be compared to the baseline to indicate improvement.

* Friedrich Bessel makes the first accurate measurement of distance to a star.

In practical conditions and measurement, the multipath time is computed by considering as last impulse the first one which allows to receive a determined amount of the total transmitted power ( scaled by the atmospheric and propagation losses ), e. g. 99 %.

When the input is a pure sine wave, the measurement is most commonly the ratio of the sum of the powers of all higher harmonic frequencies to the power at the first harmonic, or fundamental, frequency:

A short distance further, below Brugg it receives first the Reuss, and shortly afterwards the Limmat.

* 1888 – Bertha Benz drives from Mannheim to Pforzheim and back in the first long distance automobile trip, commemorated as the Bertha Benz Memorial Route since 2008.

If the object point be infinitely distant, all rays received by the first member of the system are parallel, and their intersections, after traversing the system, vary according to their perpendicular height of incidence, i. e. their distance from the axis.

In addition to the towns and monuments noted below, the Black Forest is crossed by numerous long distance footpaths, including some of the first to be established.

* Bertha Benz ( 1849 – 1944 ), German marketing entrepreneur who was the first to drive an automobile for a long distance

The distance eventually became fixed at 26 miles 385 yards, or 42. 195 km, though for the first years it was variable, being around — the approximate distance from Marathon to Athens.

A good example from the late 1980s was the Ordnance Survey's first digital maps, where the absolute positions of major roads were sometimes a scale distance of hundreds of metres away from ground truth, when shown on digital maps at scales of 1: 250, 000 and 1: 625, 000, because of the overriding need to annotate the features.

The car was first called Solitude, but got its final name from the several long distance speed records it made on the Autodromo Nazionale Monza in Italy in November 1956.

Clay pigeons are fired off two at a time from a first person perspective and are aimed into the distance.

The University of London claims to be the first university to offer distance learning degrees, establishing its External Programme in 1858.

The Open University of the United Kingdom ( UKOU ), established in 1969 as the first educational institution in the world wholly dedicated to open and distance learning, still relies heavily on print-based materials supplemented by radio, television and, in recent years, online programming.

The South Galatian view holds that Paul wrote Galatians before or shortly after the First Jerusalem Council, probably on his way to it, and that it was written to churches he had presumably planted during either his time in Tarsus ( he would have traveled a short distance, since Tarsus is in Cilicia ) after his first visit to Jerusalem as a Christian, or during his first missionary journey, when he traveled throughout southern Galatia.

The first explanation, that an effect propagated instantly, across a distance, is in conflict with the theory of relativity.

The scale length divided by this value yields the distance from the nut to the first fret.

That distance is subtracted from the scale length and the result is divided in two sections by the constant to yield the distance from the first fret to the second fret.

Before Guam's inclusion, calling the U. S. required dialing the international 011 first, thus resulting in higher long distance rates and less frequent calls to the U. S. by relatives in Guam.

The early colonial governors held an almost autocratic power due to the distance from and poor communications with Great Britain, until 1824 when the New South Wales Legislative Council, Australia's first legislative body, was appointed to advise the governor.

Having gained 8, 030 km per hour in speed, the spacecraft flew by Earth twice, the first time at a range of 960 km at 20: 34: 34 UT on 8 December 1990 before approaching the minor planet 951 Gaspra to a distance of 1, 604 km at 22: 37 UT on 29 October 1991.

Coriolis was the first to coin the term " work " for the transfer of energy by a force acting through a distance.

He was the first European to ascend the river for a distance considerable enough to make important observations.

The factual content of the work tends to be deemed more credible as it discusses more recent times, as the distance in time between the events described and the composition of the saga was shorter, allowing traditions to be retained in a largely accurate form, and because in the twelfth century the first contemporary written sources begin to emerge in Norway.