Places · Impact site
Manicouagan crater
The ring-shaped lake is the flooded rim of a 100 km crater 214 million years old — one of the most recognisable impact structures from orbit.
- Where
- Quebec, Canada
- Coordinates
- 51.38°N 68.70°W
- Age
- 214 million years ago
- On the map
- Show me
The sky from here
This is a zone 1 sky — pristine on the nine-grade scale, Bortle 1–2, reaching roughly magnitude 7.2–8.0 unaided. 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.
That grade puts 107 of the catalogue within easy reach of 10×50 binoculars and 107 within a 130mm — 58 of them need no instrument at all. There is nowhere darker worth driving to; this is already among the better skies on the planet.
58 nights a year are written off before you start: from 24 May to 20 July the Sun does not sink eighteen degrees below the horizon, and nothing faint can be seen at any hour of them.
The galactic centre tops out at 10° from this latitude — low enough that the busiest part of the Milky Way is always behind the most atmosphere, which is what separates this sky from a southern one. Of the 110 Messier objects, 21 never set from here and every one of them rises at some point in the year.
Of everything in the catalogue, Whirlpool Galaxy, Spindle Galaxy and Sunflower 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.
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 51.38°N 68.70°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 Manicouagan crater?
Everything south of declination −39°. From 51.4°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 Manicouagan crater 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 24 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. The measure is astronomical darkness — the Sun a full eighteen degrees under — not simply the hours between sunset and sunrise.
When is the Milky Way best from Manicouagan crater?
Not when it is highest, which is the frustration of observing from 51.4°N. Mid-June puts the galactic centre on the meridian at midnight and also falls inside the weeks when this latitude has no true darkness, so the two best things about summer cancel each other out. The answer in practice is late August, with the core lower in the south but a genuinely dark sky behind it.
How far is Manicouagan crater from the other sites on this map?
Mont-Mégantic is the nearest thing to it here — 683 km to the south. The nearest other impact site is Sudbury Basin, 1,050 km to the south-west. These are straight-line distances over the surface, not driving distances, and in this part of the world the two can differ considerably.