The heyday of Islamic astronomy ended before there were telescopes. Azophi (European transliteration of "Al Sufi"), a Persian naked eye astronomer, described it as a "little cloud" in the mid 900s. He also first observed and described the Magellanic Clouds.
In 1612 it was Marius, a German astronomer/astrologer, first observed Amdromeda with a telescope and said that it looked like a candle shining through horn. That's probably the description that you're alluding too. Burnham quotes Marius in his essay on M31 in the Celestial Handbook.
Can you name another current hobby where participants discuss other participants who participated in the 900s and 1600s? If law is the second oldest profession, astronomy must be the second oldest hobby.
As for Messier, most of his observing occurred from an urban Parisian rooftop at the Hotel de Cluny. It's now a museum to the "Middle Ages" with some very nice gardens.http://tinyurl.com/ccg7msm
Paris in Messier's day was a dirty, wood and coal heated, dank, smelly, and (for a pre-industrial city) well-illuminated city. La Ville-Lumière
by edict of Gabriel Nicolas de la Reynie became Europe's first illuminated city in the late 1600s. Parisians were required to keep candles burning in each street-facing window, primarily for crime suppression since de la Reynie also established the metropolitan police force.
If I had to guess, I'd say that by midnight, atop the Hotel de Cluny, Messier might have enjoyed Magnitude 5 skies or a little better at zenith. I'd guess low transparency due to the miasma of smoke, ash and noxious vapors from the city's poor sanitation was as much an issue as illumination. I'd also bet that his telescopes fell a darned sight short of "diffraction limited" in optical quality.
Old Chuck didn't have it so easy, really.