The constellation dates from antiquity, and is said to have been introduced by the Greek philosopher Thales around 600 BC. For as long as ships have sailed the seas Polaris has been an essential guiding star.
However the Pole Star isn't, as one might think, constant, but rather it changes gradually through several thousands of years. The earth's axis moves very slowly, like a top, completing a circular path every 25,800 years. During this "precessional cycle" several stars take turns becoming the Pole Star.
The present pole star, alpha Ursae Minoris, will be at the closest to the pole in 2102 AD, at which time it will only be 27' 31" from the north pole. However beta UMi (Kochab), the brightest star in the constellation, is sometimes closer to the pole than is alpha, as it was 3000 years ago.
The brightest Pole Star is Vega (alpha Lyrae), which will resume this title in another 12,000 years. Another star which periodically becomes the Pole Star is Thuban (alpha Draconis), as it was some 4600 years ago, at the time of the pyramid building in Egypt.
Traditionally amateur astronomers have used the constellation as a rough guide on the clarity of the evening's sky. The stars range from second magnitude down to fifth (and even sixth); if these latter stars are clearly seen, it's a good night for viewing.
Stars In Ursa Minor
Polaris - North Star
Polaris is a lovely yellow star with a fine deep yellow companion. Of course, one of the most important stars in the sky because of it's proximity to the North Celestial Pole less that 1/2 a degree away.
It is Believed the small object orbiting around Polaris in the picture is in fact a planetary body commonly known as a brown dwarf in the constellation of Ursa Minor
Unlike planets, brown dwarfs most likely form the same way stars do, condensing out of an interstellar cloud. Planets on the other hand, form from a disk of gas which surrounds a newly formed star. Brown dwarfs will also have more star-like convection currents in the atmosphere and probably no solid core.
Galaxies In Ursa Minor
Polarissima Borealis (NGC 3172)
A spiral galaxy in the constellation Ursa Minor, which is the closest NGC object to the North Celestial Pole. Because of its proximity - less than 1 degree from that most northerly declination -it received the name Polarissima Borealis.
NGC 5034
NGC 5034 a small galaxy in ursa minor. Right Ascension (J2000): 13h 12m 19.1s Declination (J2000): +70º 38' 58" . Visual Magnitude: 13.5 Surface Brightness: 12.8. Blue Magnitude: 14.2
NGC 5939
NGC 5939 a spiril galaxy in ursa minor. Right Ascension (J2000): 15 : 24.8 and Declination (J2000): +68 : 45". Magnitude: 13. p
NGC 6324
NGC 6324: a galaxy in ursa minor. Right Ascension : 05.4 (hours : minutes) and Declination: +75 : 25 (degrees : minutes) Apparent Magnitude: 13. p
NGC 2256
NGC 2256 in Ursa Minor RA: 17h 03m 42.0s Dec: +78 43' 00" spotted a clump of galaxies, need more time on these. Saw NGC 6331 mag15.4 and unidentifiable clumps for another night.
NGC 6071
NGC 6071 (mag. +16,8) Discovery: 6 February from Tom Boles. Position: R.A. = 16h02m08s.11, Decl. = +70°24' 55".5. Offset:4".8 And 5".9 S
Planetary Destination In Ursa Minor
HD 150706 (GO V)
Parent Star: HD 150706 (GO V) in the constellation of Ursa Minor is located at a distance of 88.71 Light Years from our Solar system. Co-ordinates of Right Ascension: 16 31 17.5856 & Declination: 79 47 23.189. The apparent Magnitude of the star is 7.029. The Inner Edge of Habitability Zone is 0.48 AU & the Outer Edge of Habitability Zone: 1.5 AU. Orbiting around HD 150706 is planet HD 150706 b the planet is believed to be a Water Cloud Jovian and its exitence has been confirmed. The planets appearance is white water ice clouds and the planet is possioned at inner edge of habitabilty zone at Mean Orbital Distance of 0.82 AU. The estimated mass of the planet is 1 Jupiters. The planet Orbits around the star every 264 ± 5.8 Days, and was discovered by M. Mayor, D. Naef, F. Pepe, D. Queloz, N.C. Santos, S. Udry on 18 Jun 2002.
