NGC891 or Caldwell 23 is a spiral galaxy 31 M light years away in the constellation Andromeda. It was discovered by Caroline Herschel in 1784. It has a flying saucer apperance because we see it edge on and the dust lane common to sprial galaxies is very prominent.
Details
Data taken between 2018-12-30 and 2019-03-04
20" f/4.6 telescope at the SDG Observatory of Garry Sedun in Arizona. TeleVue 3" Paracorr coma corrector and Moravian G3 16200 camera with off axis ZWO ASI 174 mini guiding camera and Optec Gemini Focusing Rotator. Mount - Paramount ME Exposures - used 50 B. 56 G, 54 L and 41 R subs each 300s with darks and bias, but no flats for calibration. Processing in Pixinsite and Photoshop.