The Celestial Sphere from Latitude 45° North

2100 Hours Sidereal Time

The sky from 45°N at 2100 hours sidereal time

This page contains a description of the stars, constellations, and deep-sky objects that can be seen in the sky at around 2100 hours sidereal time. It is assumed that the observer is located at approximately 45° latitude north.

To use the sky map, orient it so that the direction you are facing is at the bottom of the map. Zenith, the point directly overhead in the sky, is located at the centre of the map.

Looking North

The bright star disappearing in the northwest is Arcturus in the constellation Boötes. This kite-shaped figure seems to stand erect on its brightest star. Following Boötes around the sky is the half-circle of stars that comprises Corona Borealis.

Looking around to the north, the 'Big Dipper', part of the much larger constellation Ursa Major is low to the horizon. The two stars at the end of the dipper point upwards to the current pole star, Polaris, in Ursa Minor. Winding its way between these two constellations is Draco whose lozenge-shaped head never strays far from the brilliant blue-white star Vega which is high overhead.

Very high in the northern sky is Cepheus but his consort Cassiopeia, represented by a W-shaped group of stars, is much better known and nearby is Perseus. The bright object very low in the northeast is Capella in the constellation Auriga. The rising of this star heralds the arrival of the bright winter stars in Taurus, Orion, Gemini and Canis Major.

Looking South

Just rising in the east is the large but faint constellation of Cetus. Preceding it across the sky is another watery constellation, Pisces, a member of the zodiac. However, it is easier to locate the two constellations above Pisces which are Andromeda and Pegasus. The asterism of the 'Great Square' of Pegasus stands out high in the eastern sky. Andromeda, the daughter of Cepheus and Cassiopeia in mythology, is attached to the upper left star of the 'Great Square' and contains the farthest object visible to the naked eye, M31, the Andromeda Galaxy. This spiral galaxy seems to be broadly similar to our own Milky Way but is located approximately 2.5 million light years away.

Aquarius is getting easier to find as the it rises higher in the sky. Just below this unexceptional constellation is the bright star Fomalhaut in Piscis Austrinus. Triangle-shaped Capricornus is due south. Also due south but much higher in the sky is the 'Northern Cross', the popular name for the constellation Cygnus. Its brightest star, Deneb, stands nearly at zenith. With Vega in Lyra to the west and Altair in Aquila to the south, Deneb makes up the asterism of the 'Summer Triangle'.

Disappearing from view in the southwest is Sagittarius, never easy to see from far northern latitudes. The collection of faint stars low in the west belongs to Ophiuchus and his snake Serpens. Higher in the western sky, between Lyra and Corona Borealis, is the constellation of Hercules. On the right side of the 'Keystone' of Hercules is M13, a globular cluster, which can be seen with the naked eye.