According to the Cologne Cathedral's English website (now decimated to a single page):
Service hours Masses at Cologne Cathedral are held at the following times: Working days (Monday to Saturday): Mass: 6.30 a.m., 7.15 a.m., 8.00 a.m., 9.00 a.m., and 6.30 p.m. Devotion: Monday to Friday, 6.00 p.m.
Sundays: Mass: 7.00 a.m., 8.30 a.m., 10.00 a.m., 12 midday, 5 p.m., and 7 p.m. Divine Office: 6.00 p.m.
Please consult also our up-to-date Mass times page.
I want to attend such an event, for secular and artistic reasons only (I am not a Christian). I want to consult the best time to attend such an event (e.g. maybe the "Divine Office" is the longest and most impressive). Do all the masses include an organ and a choir?
What is the best time to visit a mass in Cologne Cathedral to get the most out of the artistic experience? Any tip regarding experiencing a mass (specifically one in Cologne Cathedral) will be welcomed.
I am not a Christian, so I have no clue which mass or service is being considered more important or festive, so names like "high mass", "devotion" and "divine office" are meaningless to me.
One last note: to make "impressive" less prone to opinion-based interpretation I would define a mass as impressive if it is long enough and includes a choir and a pipe organ. Also, a mass is more impressive if it is held in the main nave and choir, not in a side chapel.