NGC6946 8.9 (mag) 11 x 10 (arc min), the “Fireworks Galaxy,” lies between 10 and 20 million light-years away on the border between the constellations of Cepheus and Cygnus, and was discovered by Sir William Herschel (1738-1822) on September 9, 1798. It continues to fascinate astronomers, who estimate that it contains about half as many stars as the Milky Way. They often use it to study and characterize the evolution of massive stars and the properties of interstellar gas.
NGC 6939, approx. 40 arc minutes northwest of NGC 6946, is located at a distance of approximately 5,800 light years. NGC 6939's total brightness is about 8th magnitude and it contains about 80 stars in its 8 arc-minute diameter and its brightest member is about 12th magnitude.