Places · Dark sky
Pic du Midi Dark Sky Reserve
A reserve built around a working observatory on a 2,877 m summit, reachable by cable car — one of the few places where the public can sleep beside a research telescope.
- Where
- Hautes-Pyrénées, France
- Coordinates
- 42.94°N 0.14°E
- Since
- 2013
- On the map
- Show me
- More
- darksky.org
The sky from here
This is a zone 4 sky — suburban edge on the nine-grade scale, Bortle 4–5, reaching roughly magnitude 5.7–6.5 unaided. The Milky Way is a faint band overhead and gone lower down. The sky is noticeably grey rather than black.
That grade puts 99 of the catalogue within easy reach of 10×50 binoculars and 100 within a 130mm — 21 of them need no instrument at all. Genuinely dark sky — zone 2 or darker — starts about 243 km north-west.
There is no season here in which the sky fails to get properly dark — the Sun clears eighteen degrees below the horizon on all 365 nights.
The centre of the galaxy only ever reaches 18° 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, 14 never set from here and every one of them rises at some point in the year.
Of everything in the catalogue, Sunflower Galaxy, Andromeda Galaxy and Cat's Eye Galaxy are the best served here, climbing to within a few degrees of straight up — 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.
Whirlpool Galaxy, Little Dumbbell and Pinwheel Galaxy 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 42.94°N 0.14°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 Pic du Midi Dark Sky Reserve?
Everything south of declination −47°. From 42.9°N that is a cap 43° in radius centred on the south celestial pole, which is 13% 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 Pic du Midi Dark Sky Reserve get?
From about 4 hours 2 minutes at the thin end of the year, near 21 June, up to 11 hours 34 minutes around 21 December. The measure is astronomical darkness — the Sun a full eighteen degrees under — not simply the hours between sunset and sunrise. Unlike sites further from the equator, no part of the year here is written off entirely.
When is the Milky Way best from Pic du Midi Dark Sky Reserve?
Mid-June at its highest, with a workable season either side of it running from about May into September. Because 42.9°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 Pic du Midi Dark Sky Reserve from the other sites on this map?
Madrid Deep Space Complex is the nearest thing to it here — 459 km to the south-west. The nearest other dark sky is Exmoor National Park, 955 km to the north. These are straight-line distances over the surface, not driving distances, and in this part of the world the two can differ considerably.