Observer's guide
About NGC 891
NGC 891 (C23) is catalogued as a galaxy in Andromeda. Its J2000 position is RA 02:22:33, Dec +42:20:57, corresponding to 35.6371 degrees RA and 42.3483 degrees Dec. The local catalogue places it about 31,000,000 light-years away. Its referenced angular extent is approximately 12.3 by 2.45 arcminutes.
Observing tips
This is rated as a very hard target at magnitude 10.8. It is associated with autumn observing, with midnight placement typically strongest around October. From 52 degrees north its theoretical meridian altitude is about 80.3 degrees; local horizons and the live altitude chart determine the practical window.
Because it is faint, use a larger aperture where possible, avoid bright Moon conditions, and use averted vision.
What to expect
The SIMBAD classification for the matched source is H2G. SIMBAD records the morphology as SA(s)b?. A published radial velocity value is 528 km/s. The SIMBAD record currently connects it to 1755 bibliographic references.
At roughly 12.3 arcminutes across, it benefits from a narrower field and adequate image scale. Use the listed 12.3 by 2.45 arcminute extent to check framing, and treat catalogue magnitude as integrated brightness rather than a direct measure of visual contrast.