Terraformed Mars in the 19th Century

[Dalex]

Lights of cities? No. Definitely not, the telescopes were not nearly powerful enough back then and Martian cities are supposed to be "victorian-like" so no city size of Oregon.

But there is something they might be able to see and it would be pretty informative. Forest fires, the big ones like those two years ago in Russia. All you need is random asteroid, volcanic eruption or just very dry season and you can have a nice light.