Places · Dark sky
Exmoor National Park
Europe's first designated dark-sky reserve. On a good night the Milky Way casts a faint shadow here, which almost nobody in southern England has ever seen.
- Where
- England, United Kingdom
- Coordinates
- 51.13°N 3.66°W
- Since
- 2011
- On the map
- Show me
- More
- darksky.org
The sky from here
The sky over this spot is zone 3 — rural transition, Bortle 3–4, with a naked-eye limit around magnitude 6.2–7.0. The Milky Way is clearly there but loses its detail near the horizon. Light domes are obvious in several directions.
Against that sky 106 of the 110 Messier objects are straightforward in 10×50 binoculars and 106 in a 130mm, with 38 reachable by eye alone. The nearest sky of Bortle 2 or better lies about 67 km west of here.
Between 25 May and 18 July the Sun never gets eighteen degrees below the horizon from this latitude, so there is no astronomical darkness at all for those 55 nights. Nothing faint is observable in that window, however far you drive from the nearest town.
The centre of the galaxy only ever reaches 10° above the horizon from here, so the richest part of the Milky Way is always seen through the thickest air. It is the single biggest difference between this sky and one further south. Of the 110 Messier objects, 21 never set from here and every one of them rises at some point in the year.
The sky here is kindest to Whirlpool Galaxy, Spindle Galaxy and Sunflower Galaxy, 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.
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 51.13°N 3.66°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 Exmoor National Park?
Everything south of declination −39°. From 51.1°N that is a cap 51° in radius centred on the south celestial pole, which is 19% of the whole celestial sphere. That part of the sky is not merely a winter object or a difficult one; it is geometrically unavailable from this latitude. The equivalent cap around the north celestial pole is the compensation, and it never sets.
How many hours of true darkness does Exmoor National Park get?
Anything from 12 hours 1 minutes down to none whatsoever. Around 21 December the night is as long as it gets here, and around 25 May the sky simply never finishes darkening — a problem no amount of driving solves, because it is the Sun's depression angle and not the streetlights. Astronomical darkness is the Sun more than eighteen degrees below the horizon, which is a stricter thing than the Sun being down.
When is the Milky Way best from Exmoor National Park?
Late August, as a practical matter — not June, when it is highest. The galactic centre crosses the meridian at local midnight around 17 June everywhere on Earth, and from 51.1°N that date falls inside the stretch of summer when the sky never finishes getting dark. The core is therefore at its best in precisely the weeks it cannot be seen. By late August it is still up in the evening and the nights have come back, and that overlap is the whole northern season for it.
How far is Exmoor National Park from the other sites on this map?
Its closest neighbour on this map is Bannau Brycheiniog Dark Sky Reserve, 85 km away to the north. That is also the nearest other dark sky, with the next one 955 km beyond it. Distances are great-circle, so they are what a signal covers rather than what a road does.