It has also been called "Bessel's Star" or "Piazzi's Flying Star". ==Observation history== ===Early observations=== The first well recorded observation of the star system using optical instruments was made by James Bradley on 25 September 1753, when he noticed that it was a double star.
His observations led to the conclusion that binary stars were separated enough that they would show different movements in parallax over the year, and hoped to use this as a way to measure the distance to the stars. In 1792, Giuseppe Piazzi noticed the high proper motion when he compared his own observations of 61 Cygni with those of Bradley, made 40 years earlier.
Of apparent magnitude 5.20 and 6.05, respectively, they can be seen with binoculars in city skies or with the naked eye in rural areas without photopollution. 61 Cygni first attracted the attention of astronomers when its large proper motion was first demonstrated by Giuseppe Piazzi in 1804.
Piazzi's repeated measurements led to a definitive value of its motion, which he published in 1804.
Peters calculated a better value based on observations made by Bernhard von Lindenau at Seeburg between 1812 and 1814; he calculated it to be 470 ±510 mas.
Von Lindenau had already noted that he had seen no parallax, and as Friedrich Georg Wilhelm von Struve pointed out after his own test series between 1818 and 1821, all of these numbers are more accurate than the accuracy of the instrument used. Friedrich Wilhelm Bessel made a notable contribution in 1812 when he used a different method to measure distance.
Peters calculated a better value based on observations made by Bernhard von Lindenau at Seeburg between 1812 and 1814; he calculated it to be 470 ±510 mas.
He then followed this up with direct parallax measurements in a series of observations between 1815 and 1816, comparing it with six other stars.
He then followed this up with direct parallax measurements in a series of observations between 1815 and 1816, comparing it with six other stars.
Von Lindenau had already noted that he had seen no parallax, and as Friedrich Georg Wilhelm von Struve pointed out after his own test series between 1818 and 1821, all of these numbers are more accurate than the accuracy of the instrument used. Friedrich Wilhelm Bessel made a notable contribution in 1812 when he used a different method to measure distance.
Von Lindenau had already noted that he had seen no parallax, and as Friedrich Georg Wilhelm von Struve pointed out after his own test series between 1818 and 1821, all of these numbers are more accurate than the accuracy of the instrument used. Friedrich Wilhelm Bessel made a notable contribution in 1812 when he used a different method to measure distance.
All of these estimates, like earlier attempts by others, retained inaccuracies greater than the measurements. When Joseph von Fraunhofer invented a new type of [Bessel carried out another set of measurements using this device in 1837 and 1838 at
In 1838, Friedrich Bessel measured its distance from Earth at about 10.4 light-years, very close to the actual value of about 11.4 light-years; this was the first distance estimate for any star other than the Sun, and first star to have its stellar parallax measured.
All of these estimates, like earlier attempts by others, retained inaccuracies greater than the measurements. When Joseph von Fraunhofer invented a new type of [Bessel carried out another set of measurements using this device in 1837 and 1838 at
All text is taken from Wikipedia. Text is available under the Creative Commons Attribution-ShareAlike License .
Page generated on 2021-08-05