EntityQ427293· pop 28· linked from 197 articlesoctantSign in to savemeasuring instrument used primarily in navigation; type of reflecting instrumentConnectionscircular sectorEntityastronomy in medieval IslamEntityMuḥammad ibn Ibrāhīm al-FazārīEntityBackstaffEntityLunar distanceEntityFranceCountryIsaac NewtonPersonuniverseEntityPhiladelphiaEntitygalaxyEntitygravityEntityAvicennaEntitytinEntityInternational Standard Book NumberEntityOmar KhayyámEntityMuḥammad ibn Musa al-KhwarizmiEntitytelescopeEntityIslamic calendarEntitycompassEntityAverroesEntityCategoriesAngle measuring instrumentsAstronomical instrumentsCelestial navigationNavigational equipment