The original intention with this picture was to take 5 hours of sub frames of the Cave nebula (Caldwell 9), aka Sh2-155 in Cepheus. However, a problem with the focusser meant that after the first 90 minutes the remaining images were offset in RA. Fortunately, there was enough overlap to enable me to join the images in a wide field mosaic. The bright cluster bottom left is M52.
There’s some residual light pollution down the centre of the image. This is very hard to deal with in mosaics. Also, there’s a lot more noise in the right hand side due to the relative lack of exposures.
