Общая Астрономическая Конференция > Практика > Астрономические наблюдения > Оценим наше небо! ... Просмотр полной версии : Оценим наше небо! ... The Bortle Dark-Sky Scale . ... A fully dark adapted observer should be able to spot it under skies good enough to rate Class 4 or better on the author's dark-sky scale. ... Thus, upon finding a semirural observing site where stars of magnitude 6.0 to 6.3 are marginally apparent to the unaided eye, they believe they have located an observing Nirvana! ...