Diagram caption: The constellation Delphinus with its brighter stars and surrounding constellations. Delphinus is surrounded by (going clockwise from the top): Vulpecula, Sagitta, Aquila, Aquarius, Equuleus and Pegasus. Delphinus is a relatively small constellation with few bright stars.

Delphinus lies just north of the celestial equator and thus the whole constellation is visible at some point in the year to all but the most antarctic regions. The constellation is best viewed in the evenings in the early northern hemisphere autumn and early southern hemisphere spring.

The globular cluster NGC 6934 lies in Dephinus. It is marked here with a yellow circle with a plus sign superimposed on it.

The y-axis of this diagram is in degrees of declination with north as up and the x-axis is in hours of right ascension with east to the left. The sizes of the stars marked here relate to the star's apparent magnitude, a measure of its apparent brightness. The larger dots represent brighter stars. The Greek letters mark the brightest stars in the constellation. These are ranked by brightness with the brightest star being labeled alpha, the second brightest beta, etc., although this ordering is not always followed exactly. The dotted boundary lines mark the IAU's boundaries of the constellations and the solid green lines mark one of the common forms used to represent the figures of the constellations. Neither the constellation boundaries, nor the lines joining the stars appear on the sky.

Diagram credit: Adapted by the IAU Office of Astronomy for Education from the original by the IAU and Sky & Telescope. Credit Link

Related glossary terms: Apparent Magnitude , Aquarius , Celestial Coordinates , Celestial Equator , Constellation , Declination , Globular Cluster , Right Ascension (RA)
Categories: Naked Eye Astronomy

Diagram license: Creative Commons Attribution 4.0 International (CC BY 4.0) Creative Commons Attribution 4.0 International (CC BY 4.0) icons