[DOC] [TLE] Stellar parallax - Wikipedia [PAR] Then in 1838 Friedrich Bessel made the first successful parallax measurement 
ever, for the star 61 Cygni, using a Fraunhofer heliometer at Knigsberg... [DOC] [TLE] Measuring distances to stars via parallax [PAR] The smallest angle one can measure from the ground with an optical telescope is 
... Astronomers need a VERY long baseline in order to produce a parallax angle 
which ... Give it a try: the first star to have its parallax measured was 61 Cygni. In 
1838, Friedrich Bessel calculated its parallax half-angle to be  = 0.314 arcsec. [DOC] [TLE] Parallax - Cosmic Distance Ladder - NAAP - UNL Astronomy [PAR] It is the observed location of one object with respect to another  nothing more. ... 
distant objects first throught one eye alone and then through the other eye. ... a 
stellar parallax were made by Friedrich Bessel in 1838, for the star 61 Cygni. ... 6 
months and measure the position again relative to the much more distance stars. [DOC] [TLE] The Distances to Nearby Stars | Astronomy 801: Planets, Stars ... [PAR] Since this shift was not observed by the Greeks, nor by later astronomers like ... 
The first scientist to do so was Friedrich Bessel in 1838. ... We can setup a right 
triangle if we use half of the measured angle that the star appears to move in 6 
months. ... To calculate the parallax of any star, you can use the same 
trigonometric... [DOC] [TLE] Seeing Earth's Orbit in the Stars: Parallax and Aberration - arXiv.org [PAR] measure the annual parallax of stars using telescopes. None of them succeeded. 
Annual stellar parallax was not successfully measured until 1838, when Friedrich
. Bessel detected the parallax of the star 61 Cygni.2 But the early failures to ... 
and observations are made from opposite sides of Earth's equator (the points O1. [DOC] [TLE] parallax | optics | Britannica.com [PAR] The largest measured stellar parallax is 0.75, for the nearest star, Alpha ... With 
an angular distance z from the zenith, Z, it can be found from the ... In practice, 
stars near the Moon are observed also to eliminate errors of refraction and 
instruments. .... Friedrich Wilhelm Bessel was the first to measure stellar parallax 
in 1838. [DOC] [TLE] The ABC's of Distances [PAR] Jul 25, 2016 ... A star with a parallax of 1 arc-second has a distance of 1 parsec. ... The first 
stellar parallax (of the star 61 Cygni) was measured by Friedrich Wilhelm Bessel (
1784-1846) in 1838. ... the angular expansion rate d(theta)/dt using pictures 
taken many years apart, and; the radial velocity of expansion, VR, using... [DOC] [TLE] Gaia - The University of Sydney [PAR] the stars? We use exactly the same methods that surveyors use ... and the 
Hellespont (~500 km apart) ... In order to measure distances to stars, the only 
baseline long enough is the ... 1838: Friedrich Bessel measures the parallax of 
the star. 61 Cygni: it ... By observing from space, Hipparcos avoided many of the 
problems... [DOC] [TLE] Friedrich Wilhelm Bessel facts, information, pictures | Encyclopedia ... [PAR] Get information, facts, and pictures about Friedrich Wilhelm Bessel at ... Bessel 
made his first time determination with a clock and a sextant that had been built to 
.... If this angle  can be measured, then the distance r of a star can be obtained 
from ... After observing for eighteen months, by the fall of 1838 Bessel had 
enough... [DOC] [TLE] Astrometry [PAR] Jan 15, 2014 ... No one technique can measure distances at all ranges encountered in ... From 
Earth, the greatest parallax angle is obtained with two measurements 6 months 
apart, from ... to a nearby star was carried out in 1838 by Friedrich Bessel at the ... 
The lack of observed stellar parallax at the time was used as the... [DOC] [TLE] How Are Distances to Stars and Galaxies Calculated? [PAR] Jan 1, 2016 ... As of the present date, the most distant observed galaxy is some 13.2 billion ... An 
interesting online tool, which one can use to determine first-

Question: In 1838 Friedrich Bessel first measured a star's distance by using parallax--using observations this many months apart
Answer: 6