The Cave Nebula, Sh2-155 or Caldwell 9, is a dim and very diffuse bright nebula within a larger nebula complex containing emission, reflection, and dark nebulosity. It is located in the constellation Cepheus and is approximately 2400 light years from Earth.
M: Avalon linear fast Reverse
T: Takahashi FSQ85 0.73x
C: QSI690-wsg with 3nm NB filters
21 hours total integration time.