A star’s latitude or position north or south of the celestial equator is called declination, while its longitude or position east or west is called right ascension and measured in hours, minutes, and seconds. The position of all stars and deep sky objects on the celestial sphere is mapped relative to the celestial equator and poles, just as different locations on Earth are mapped using the equator and Greenwich, England. Similarly, the constellation Ursa Minor, which contains Polaris, the closest bright star to the north celestial pole, cannot be seen from most places south of the equator. Crux, also known as the Southern Cross, which is prominent enough in the southern sky to be featured on several national flags in the southern hemisphere, can never be seen from most locations north of the equator. While some of the southern constellations can be seen from northern latitudes at certain times of year – Scorpius, for instance, is visible over the southern horizon in the summer – others never rise over the horizon. Observers can never see all 88 constellations from a single location on Earth. Southern hemisphere sky map, image: Roberto Mura With the celestial poles on the horizon, all stars appear to rise in the east and set in the west for observers at the equator. Near the equator, there are no circumpolar stars. The stars that are close to the poles never set below the horizon for observers in locations where the stars are visible: they are circumpolar. The farther they are from the poles, the wider the circle the stars make across the night sky. Students will match the names of the following constellations to the constellation diagram: Great Bear, Gemini, Persues, Cassiopeia, Cepheus. Objective: Identify five constellations visible in the Northern hemisphere all year. Polaris and other stars lying near the celestial poles appear to move across a smaller area than stars lying closer to the equator. MatchCard Science Northern Constellations Worksheet Worksheet. The south celestial pole is a bit trickier to pinpoint because there are stars visible to the unaided eye marking its location. The north celestial pole can be easily located because it is marked by Polaris, a relatively bright star located in Ursa Minor constellation. Similarly, the Earth’s North and South Poles, extended into space, mark the north and south celestial poles. The celestial sphere, an imaginary sphere surrounding Earth, is divided into the northern and southern hemispheres by the line of the Earth’s equator, extended into space. ![]() Northern hemisphere map, image: Roberto Mura
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