I've seen it at a couple places. One is Lowell observatory in Flagstaff AZ. They have pretty good light conditions despite being in a city. Second is in certain

I've seen it at a couple places. One is Lowell observatory in Flagstaff AZ. They have pretty good light conditions despite being in a city. Second is in certain national parks which tend to be away from any big city. Third was on a plane flight over the pacific ocean.