This impressive and bright emission nebula in Cygnus, more commonly known as the Tulip Nebula, lies very close to η-Cyg (mag 3.89) and spans 8.8 light-years in diameter.
Lying at a distance of 8,750 light-years away, the excitation of hydrogen and the consequent nebula emission is attributed to the O6.5III class star HD 227018 (mag 9.02) (see the bluish star in the lower half of the nebula below and lying to the immediate upper right of the bright orange star SAO 69230 (mag 7.69)).
What is of great interest is the fact that the well-known black hole candidate Cygnus X-1 lies very close to the Tulip Nebula and which is just outside the field of view at the bottom right corner.
Technical Details:
Jul 30, 2009 @ 00:30 - 04:40 UT+3
AP 160 f/7.5 StarFire EDF, AP 1200GTO GEM, SBIG ST-10XME, SBIG CFW10, AstroDon TruBal CRGB
RRGB @ 120:60:60:60m 6-min subs, 1x1, - 12.5° C
Further details: http://www.perseus.gr/Astro-DSO-Nebulae-Sh2-101.htm