Jacksonville, IL Night Sky Brightness
Jacksonville, IL: how dark is the sky here?
Satellite radiance puts Jacksonville in the suburban band. Light dome dominates much of the sky. Only the brightest stars and planets stand out clearly. Only 65.6% of the 3,206 cities measured here read darker than Jacksonville.
This comes from a satellite measuring light radiating upward, not a person's eyes on the ground, so it isn't the same as a Bortle class, though the two track each other closely - see the Bortle scale guide for where they can disagree.
The nearest darker sky to Jacksonville
The closest place in this dataset with a meaningfully darker sky is Chatham, IL, roughly 29 miles away in a straight line, rated suburban edge. Road distance will be more.
Chatham, IL is itself still a measured city, not a designated dark-sky park, this only compares against the 3,206 places this dataset covers.
How Jacksonville compares nationally
Jacksonville, IL has a population of about 17,801, one of 3,206 US cities of 10,000 or more residents in this dataset. Jacksonville places 2,093 of 3,206 cities in this dataset's darkest-to-brightest order, ranked by the method in the methodology guide.