A very dim and diffuse emission nebula Sh2-155 is commonly referred to as the Cave Nebula.  To help overcome the dimness this image was taken through narrowband filters which bring out the ionized hydrogen, oxygen and sulfur.

OTA:  William Optics Star71

Camera:  Atik 460ex w/EFW2 filter wheel

Filters:  Astrodon Ha/OIII/SII  (3nm)  LRGB

Mount:  AP Mach1

Exposure:  Ha:OIII:SII:L:R:G:B     400:120:120:48:48:48:48 (m)  rgb bin 2x2

Data obtained:  August - November 2015

Meadowlark Ridge Observatory
Meadowlark Ridge Observatory