🌐EnglishEnglishDeutschEspañolFrançaisNederlandsPolskiРусскийالعربية한국어中文日本語EntityQ352923· pop 12· linked from 42 articlesair massoptical path length through Earth’s atmosphere for light from a celestial sourceAvailable in 11 languagesFrançaisDeutsch中文РусскийالعربيةArmenianNederlandsPolskiUzbek한국어ConnectionshorizonEntityzenithEntityCategoriesAstronomical imagingAtmospheric optical phenomenaIgnored ISBN errorsObservational astronomyOptical quantities