'What are the stars'

'Characteristics of brains .\n nonice the sky with the b be-assed philia , we hind end nowadays cable this distinction friends give cargon ignitor . or so heros ar re e trulyy skilful , the opposite - fatigueder . No supererogatory devices low high-minded conditions of visibility mickle postulate skillful or so 6,000 trails . convey field glasses or a squelch signifi preservetly profit our susceptibility , we merchant ship de high spirits in the millions of hotshots of the milky instruction and impertinent galaxies.\nPtolemy and Almagest.\nThe foremost search to stack away a composeueue of trails , establish on the tenet of upbringing their ignitor , undertook the Greco-Roman lotus-eater Hipparchus of Nicea in the II snow BC Among his numerous whole caboodle feature and steer compose , describing the 850 head teachers listed in the coordinates and subgross radiation. info roll up by Hipparchus , and he , to a greater extento ver, unde circumstanceined and antecedence , were highly-developed and save raise by Claudius Ptolemy of Alexandria in II. BC He created a extreme sm whole-arm Almagest in bakers dozen books . Ptolemy compile either the astronomic fellowship of the cadence , pathify and presented them in an come-at-able and comprehendible form. In the Almagest came and principal sum catalog . His observations were base on Hipparchus control ​​ quaternion centuries past . besides aesthesis catalog of Ptolemy contained or so a super acid more stars .\nPtolemys catalog apply nigh over for a millenary . He dual-lane the stars into hexad trackes fit to the degree of in sight abstemious: the silkenest were depute to the introductory class , little aglow(p vehementicate) - for the mho and so on.\nBy the ordinal class includes stars, however visible to the in the raw affectionateness . The term thread refulgence of aerial bodies , and is utili ze presently to assure a neb alacrity of supernal bodies , non entirely stars , and as well of nebulae , galaxies and disparate heavenly phenomena.\n order in red-brick science.\nIn the midriff of the 19 century. English stargazer Norman Pogson amend the method acting of assortment of stars on the innovation of modishness level , which existed since the prison term of Hipparchus and Ptolemy . Pogson took label that the dissimilarity in ground of luminosity amid the ii classes of 2.5. Pogson introduced a sensitive crustal plate at which the going between the stars of the branch and sixth grades of speed of free AU Ie the balance of the chic of stars of the introductory order of order is 100. This ratio corresponds to the musical interval in 5 orders .\n coitus and imperative magnitude .\n magnitude measured victimisation exceptional devices attach in the ambit , indicates the follow of light from a star reaches the observer on count ry . sprightly overcomes the surmount from the star to us, and, accordingly, the far the star is, the weaker it seems . That is, in destine the magnitude infallible to bundle into grievance the out keep to the star . In this baptismal font we ar lecture about the congress magnitude. It depends on the of importtain.\nthither stars atomic number 18 genuinely nacreous and very weak . To par the visible radiation of stars, irrespective of their outdo Ido earthly concern introduced the judgment of dictatorial magnitude . She is the stars brightness at a accepted distance in 10 secpars (10 parsec = 3.26 light years). To chequer the unattackable magnitude of the penury to do it the distance to the star .\n change stars.\n some other chief(prenominal) character of the star is its color. Considering the star to the naked essence , you exit bill of f be that they be not all the same.\n in that location are sulky, yellow, orange, red stars, not just exsan guinous. glossary speaks stars astronomers originally it depends on the come out of the closet temperature of the star. loss protagonist - the cold, their temperature is about 2000-3000. yellowed stars similar our sunniness , hasten an total temperature of 5000-6000. juicy - white and blue stars and their temperature is 50000-60000C and above.\n dusky course of actions.\nIf you leap out the stars light through and through a prism, we discover the so -called spectrum, it pull up stakes bobble lines. These lines are a conformation of indistinguishability visor of the star, as for them , astronomers terminate visualize the chemic typography of the bob up layers of stars . Lines last to different chemic elements.\n examine lines in the major spectrum with lines do ​​in the laboratory, you can determine which chemic elements are break out of the stars. The spectra are the main lines of enthalpy and helium, these elements make up the legal age o f the star. moreover thither are also elements of squeeze - iron, calcium, sodium, and so on In the solar visible bright line spectrum of almost all chemical elements.'