86 Syrgy-Sidihtaka Delambre), and the true apparent diameters of the planets, as seen from the enrth at their geabest and leust distances. Apparef Dicters of the PRMeta, (certag to the strug-Sidddotg , to Tucko Brahae, and to Motor Sciece. ModerUB : Sorrya-Siddhanta : Tycho Planet. Bahe in yejanaB|in MIC . leael. | greatest. |
2’ 8। Mats 8a turn Mercury Jupiter, Venus 1' +। ’ 6()' 2' 1 }' 45 3 15 27 1 12 874 45 52 6} 8' ) 1' 14' This table shbox how groglly exaggerator une wont to be any deter nituations of the Tagnitude of the planetary orbs made by the unassisted oye one. This effeek is due to the well-known phenomenon of the irradia tion, which increases the apparent size of . brilliant body when seen at some distance, I wः be noticed that the Hitlu estimmtck o not greatbly exceed those of Tycho, the most noted an ecurate of १astronomical obs¥es prior to the invention of the telescope. In respect to order of magnitude they entirely agree, and both accorn with the relative apparent size of the planets, except that to Mercury and Venus, whose proportional brilliancy, from their nearness to the sum, is greator, is assigned too high a rank Tycho also established a sofile of parent diameters for the fixed stats, qछrying from 2, for the first magnitudedown to 20y, for the sixtbh 's do not find that tolemy made any similar estimates, ei blan for planets. or for fixed state. The Hindus, however, push their empiricism one step further, gravely laying down a rule by which, from those nean values, the thrue values of the apparent diameters at any लोiven time nualy be found. The fundamental bpportion is, of course, true dist. र mean dist. : : team app. dinan. : true app. diam. 'he second torm of this proportion is represented by radius: for the first we have, according to the translation given, one half the sum of radius and the fourth hypothenuBe, by which is meant the ‘‘ variable hypothenuse
- e karp) found in the course of the fourth, ot list, process for finding
the true place of the planet (see above, ii. 43-45). 'he verihoweve! (twittpkary), which is translated ff radius and the fourth hypothenue is much more naturally rendered third and fourth hypothouses and bhe latter interpretation is also mentioned by the conumentator as one