Places · Observatory
South Pole Telescope & IceCube
A 10 m millimetre-wave dish mapping the cosmic microwave background, above a cubic kilometre of instrumented ice that detects neutrinos by the light they leave passing through it.
- Where
- Amundsen–Scott Station, Antarctica
- Coordinates
- 89.99°S 0.00°E
- Since
- 2007
- On the map
- Show me
- More
- icecube.wisc.edu
The sky from here
The sky over this spot is zone 1 — pristine, Bortle 1–2, with a naked-eye limit around magnitude 7.2–8.0. The Milky Way casts a shadow. Airglow is visible, the zodiacal light reaches across the sky, and the darkest places on Earth look like this.
Against that sky 107 of the 110 Messier objects are straightforward in 10×50 binoculars and 107 in a 130mm, with 58 reachable by eye alone. There is nowhere darker worth driving to; this is already among the better skies on the planet.
Between 1 August and 11 May the Sun never gets eighteen degrees below the horizon from this latitude, so there is no astronomical darkness at all for those 284 nights. Nothing faint is observable in that window, however far you drive from the nearest town.
The centre of the galaxy reaches 29° 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, 46 never set from here and 64 never rise.
The sky here is kindest to Lagoon Nebula, Trifid Nebula and Omega Nebula, each of which passes within a few degrees of overhead — 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.
Ptolemy's Cluster, Butterfly Cluster and Southern Pinwheel never set from this latitude, so they are available on any clear night of the year rather than for one season of it.
Against that, Virgo A, Phantom Galaxy and Beehive Cluster never clear the horizon here at all. No amount of aperture or patience changes that; the only remedy is to travel.
Read at 89.99°S 0.00°E. 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 South Pole Telescope & IceCube?
Exactly half of it — the whole northern celestial hemisphere. Standing on the pole the celestial equator lies along the horizon and stays there, so nothing rises or sets at all: every star south of declination 0° circles the sky at a fixed altitude all year round, and nothing on the far side of that line ever comes up. It is the only place on Earth where the sky turns without anything appearing or disappearing over the horizon.
How many hours of true darkness does South Pole Telescope & IceCube get?
Between nothing at all and 24 hours, depending entirely on the date. The longest night falls around 13 May; around 1 January there is no astronomical darkness at any hour, however far you get from the nearest town. That counts only proper astronomical night, with the Sun eighteen degrees down; the merely-dark hours either side of it are longer.
When is the Milky Way best from South Pole Telescope & IceCube?
Around 17 June, when the galactic centre crosses the meridian at local midnight — and because this is a southern site, that is also midwinter, with the longest and darkest nights of the year underneath it. The brightest part of the Milky Way reaches its highest point on the best nights available, rather than during a summer that will not go dark. That coincidence is most of the reason the world's large optical observatories are in the southern hemisphere.
How far is South Pole Telescope & IceCube from the other sites on this map?
Aoraki Mackenzie Dark Sky Reserve is the nearest thing to it here — 5,150 km to the north. The nearest other observatory is Pierre Auger Observatory, 6,090 km to the north. Distances are great-circle, so they are what a signal covers rather than what a road does.