I discuss the current low Earth orbit artificial satellite population and show that the proposed ‘ megaconstellation ’ of circa 12,000 Starlink internet satellites would dominate the lower part of Earth orbit , below 600 km , with a latitude-dependent areal number density of between 0.005 and 0.01 objects per square degree at airmass < 2 .
Such large , low altitude satellites appear visually bright to ground observers , and the initial Starlinks are naked eye objects .
I model the expected number of illuminated satellites as a function of latitude , time of year , and time of night and summarize the range of possible consequences for ground-based astronomy .
In winter at lower latitudes typical of major observatories , the satellites will not be illuminated for six hours in the middle of the night .
However , at low elevations near twilight at intermediate latitudes ( 45-55 deg , e.g .
much of Europe ) hundreds of satellites may be visible at once to naked-eye observers at dark sites .