NGC 7822 (Sh2-171) in Cepheus

NGC 7822 (Sh2-171) is an emission nebula in the constellation of Cepheus. It is situeted in the eastern part of the constellation of Cepheus, about 9 ° north of the bright star Caph, in a stretch of the Milky Way strongly obscured by interstellar dust and unlit nebulae. It is actually the northern part of the large cloud complex of Ced 214, linked to the stellar association Cepheus OB4. It has an elongated shape in the east-west direction and in the detailed images jagged structures called elephant proboscis are well evident, globules in erosion due to the strong stellar wind coming from the massive stars of the open cluster Berkeley 59. This cluster contains nine blue stars with spectral classes between O7 and B3, among which stands out BD + 66 1673, one of the hottest stars located within a radius of 1000 parsecs from the Sun. It is an eclipse binary in which the primary star, class O5V, has a surface temperature of 45000 K and a brightness of 100,000 L⊙. Its variable star abbreviation is V747 Cephei.. Below can be seen a Ha SII OIII combination in so called "Hubble Palette":