Sh2-170 imaged from my Creedmoor site on October 11th, 2016 in Ha is an emission nebula in Cassiopeia. It lies in the Perseus arm of our galaxy around 7500 light years distant. At its centre is a small, young star cluster, Stock 18. The bright star at the centre of the nebula is ionizing the surrounding hydrogen gas and causing the nebula to glow. To give a sense of scale, the nebula is about 2/3 the diameter of the full moon.