Places · Ground station
Space Telescope Science Institute
Schedules Hubble and Webb, and holds the archive both write into — most of what either telescope has ever seen is downloadable from this building.
The sky from here
Measured at these coordinates the sky is zone 9: core, which is Bortle 9 and a naked-eye limit of about magnitude under 4.0. The brightest handful of stars, and nothing else. Orion is recognisable only by its belt.
Of the 110 Messier objects, 4 are an unaided-eye target from a sky this dark, 27 are comfortable in 10×50s and 30 in a 130mm reflector. You would have to get roughly 208 km south-east before the sky reaches Bortle 2.
Every night of the year reaches full astronomical darkness at this latitude; the Sun always gets its eighteen degrees below the horizon, which places much further from the equator cannot say.
The centre of the galaxy reaches 22° at its highest, which puts the brightest part of the Milky Way clear of the horizon murk without ever being overhead. Of the 110 Messier objects, 11 never set from here and every one of them rises at some point in the year.
Cat's Eye Galaxy, Andromeda Galaxy and Sunflower Galaxy pass close to the zenith from this latitude — an object at the zenith is being seen through the least air it will ever be seen through, and the difference against the same object low in the south is not subtle.
Little Dumbbell, Pinwheel Galaxy and Owl Nebula never set from this latitude, so they are available on any clear night of the year rather than for one season of it.
Read at 39.33°N 76.62°W. Darkness is estimated rather than measured; everything else follows from the latitude and holds along the whole parallel. How accurate this is.
Nearby
Questions
What part of the sky never rises at Space Telescope Science Institute?
Everything south of declination −51°. From 39.3°N that is a cap 39° in radius centred on the south celestial pole, which is 11% of the whole celestial sphere. It is out of reach permanently rather than seasonally: no time of year and no instrument brings it above the horizon. The matching 11% around the north celestial pole is the same geometry inverted, and never sets.
How many hours of true darkness does Space Telescope Science Institute get?
11 hours 23 minutes on the best night, around 21 December, falling to 5 hours 2 minutes around 21 June. The measure is astronomical darkness — the Sun a full eighteen degrees under — not simply the hours between sunset and sunrise. Every night of the year gets there eventually, which is the quiet advantage of not being any further from the equator than this.
When is the Milky Way best from Space Telescope Science Institute?
Mid-June at its highest, with a workable season either side of it running from about May into September. Because 39.3°N keeps full astronomical darkness all year, the whole of that season is usable, which is not the case for observers much further from the equator, who lose the peak of it to summer twilight.
How far is Space Telescope Science Institute from the other sites on this map?
Wallops Flight Facility is the nearest thing to it here — 184 km to the south-east. The nearest other ground station is Johnson Space Center — Mission Control, 2,010 km to the south-west. Measured as the great circle between coordinates, which is the shortest path across the surface and rarely the one you could travel.