NGC 247

NGC 247 is the designation for a spiral galaxy in the constellation Cetus. It has a visual angular spread of about 21 '× 7' and an apparent brightness of 8.9 mag. The galaxy is one of our Local Group of neighboring Sculptor Group and is about 3.4 Mpc (11 million light years ) away.

NGC 247 was discovered on 20 October 1784 by the German - British astronomer William Herschel.

One difficulty in determining the distance of NGC 247 is that we see from Earth, the galaxy from the side. The distance of galaxies is determined from the apparent brightness of variable stars, the Cepheids. By the side view of the light is attenuated by interstellar dust and the stars seem to be farther away. Measurements of the Araucaria project in the infrared region from 2009 showed that the absorbance was underestimated in previous studies something and led to lower by 7% distance estimation.