Changes

In Genesis, the stars were made in the fourth day,<ref>[Genesis 1-8 (Translated)|Gen 1:14]</ref> and their number is compared to the number of descendants of Abraham.<ref>[Genesis 9-16 (Translated)|Gen 15:5]; an earlier count of the number of descendants of Abraham was the number of grains of dust of the Earth (Gen 13:16)</ref>

In Genesis, the stars were made in the fourth day,<ref>[Genesis 1-8 (Translated)|Gen 1:14]</ref> and their number is compared to the number of descendants of Abraham.<ref>[Genesis 9-16 (Translated)|Gen 15:5]; an earlier count of the number of descendants of Abraham was the number of grains of dust of the Earth (Gen 13:16)</ref>

The [[Bible]] implies that the number of stars is virtually countless,<ref>[Jeremiah 27-34 (Translated)|Jeremiah 33:22]; similarly to Genesis, the number of descendants of David is compared to the number of stars and the number of grains of sand</ref> but for many years this was not accepted.  Hipparchus in 128 B.C. stated there were 1,026 stars in the sky.  [[Kepler]] in 1600 A.D. did his own count and found the number to be 1,005.  Today, thanks to telescopes (especially the [[Hubble Telescope]]) showing many stars previously too dim to be seen, we are now aware of some 70,000,000,000,000,000,000,000,000 (7×10²⁵) stars.<ref>[http://www.cnn.com/2003/TECH/space/07/22/stars.survey Star survey reaches 70 sextillion]</ref>

The [[Bible]] implies that the number of stars is virtually countless,<ref>[Jeremiah 27-34 (Translated)|Jeremiah 33:22]; similarly to Genesis, the number of descendants of David is compared to the number of stars and the number of grains of sand</ref> but for many years this was not accepted.  Hipparchus in 128 B.C. stated there were 1,026 stars in the sky.  [[Kepler]] in 1600 A.D. did his own count and found the number to be 1,005.  Today, thanks to telescopes (especially the [[Hubble Telescope]]) showing many stars previously too dim to be seen, we are now aware of some 70,000,000,000,000,000,000,000,000 (7×10²⁵) stars.<ref>[https://www.cnn.com/2003/TECH/space/07/22/stars.survey Star survey reaches 70 sextillion]</ref>

==Measuring stellar positions==

==Measuring stellar positions==

=== Distances ===

=== Distances ===

The oldest method of measuring the distance from our solar system to a distant star is the parallax method. To use this method, astronomers measure the right ascension on the sky of the star at two times of the year, half a year apart. The two measurements will differ by a small angle with respect to the most distant stars in that region of the sky. Exactly half this angle is the ''parallax angle'', having symbol ''p''. This is the angle that the star makes with the [[sun]] and the position of the [[earth]] at a right angle with that star.<ref name=Britannica3>"[http://www.britannica.com/eb/article-52809/star Star: Determining stellar distances]." ''Encyclopædia Britannica''. 2008. Encyclopædia Britannica Online. Accessed 21 Apr. 2008</ref> The distance s of the star, in astronomical units (AU), is:

The oldest method of measuring the distance from our solar system to a distant star is the parallax method. To use this method, astronomers measure the right ascension on the sky of the star at two times of the year, half a year apart. The two measurements will differ by a small angle with respect to the most distant stars in that region of the sky. Exactly half this angle is the ''parallax angle'', having symbol ''p''. This is the angle that the star makes with the [[sun]] and the position of the [[earth]] at a right angle with that star.<ref name=Britannica3>"[https://www.britannica.com/eb/article-52809/star Star: Determining stellar distances]." ''Encyclopædia Britannica''. 2008. Encyclopædia Britannica Online. Accessed 21 Apr. 2008</ref> The distance s of the star, in astronomical units (AU), is:

<math>\,\!s = \cot p</math>

<math>\,\!s = \cot p</math>