Alexandria Partial Eclipse

The city that measured the Sun

Alexandria has the strongest claim of any city on Earth to be the birthplace of quantitative astronomy, and it is worth understanding what happened here before deciding what to do on eclipse day.

Eratosthenes and the well at Syene

Eratosthenes of Cyrene ran the Library of Alexandria in the third century BC. He knew that at Syene, far up the Nile, the midsummer noon Sun cast no shadow — it stood at the zenith and lit the bottom of a well. In Alexandria on the same day, a vertical gnomon did cast a shadow, and the angle worked out at about one-fiftieth of a full circle. If the Earth were a sphere and the Sun effectively infinitely distant, the distance from Alexandria to Syene had to be one-fiftieth of the planet’s circumference. He multiplied, and got roughly 252,000 stadia — a figure that, depending on which stadion he was using, lands within a few per cent of the correct answer.

It is a beautiful piece of reasoning and it works from a shadow and a walk. Two thousand two hundred and seventy years later, the geometry of the Sun, the Moon and this same stretch of coast is being computed to the second from Besselian elements — and it is the same problem, solved with better tools.

Hypatia, Ptolemy and the rest

Claudius Ptolemy compiled the Almagest here in the second century AD, and its tables of solar and lunar motion were the basis of eclipse prediction across Europe and the Islamic world for well over a thousand years. Hypatia taught mathematics and astronomy in this city until her murder in 415. Whatever happens in the sky on 2 August, the ground you are standing on is where humanity first got serious about working out where the Sun would be.

Where to feel it today

• The Bibliotheca Alexandrina. The modern library on the Corniche, a vast tilted disc of granite facing the sea, with a planetarium in the plaza outside it. The most fitting place in the city to watch a partial eclipse, if you are staying.
• The Citadel of Qaitbay. Built in the fifteenth century on the site of the Pharos, one of the seven wonders of the ancient world, using some of its fallen stone. It sits at the tip of the eastern harbour with open sky in every direction.
• Kom el-Shoqafa and Pompey’s Pillar. Roman Alexandria underground and above it.
• The Corniche itself. Fifteen kilometres of seafront. At 76° altitude you need no view at all, but if you want the light on the water, this is where it will be.

Route one: south, through Cairo, into the valley

This is the obvious plan and the one most people will take. Alexandria to Cairo is about 180 km in a straight line, a fast and frequent train journey of roughly two to two and a half hours on the main line, or a comparable drive on the desert road. Cairo is where every onward option begins.

From there the path is still 175 km further south, so this is emphatically not a same-morning journey. Alexandria to the nearest totality is a full day’s travel in any realistic scenario. Plan it as a move, not a trip:

• To Minya — about 353 km from Alexandria in a straight line, reachable by rail via Cairo. 4m 07s of totality from 12:55:34. The shortest journey from Alexandria that gets you a genuine total eclipse.
• To Asyut or Sohag — further up the same railway line, and worth it: 6m 07s and 6m 22s respectively. Sohag has the longest totality of any Egyptian city.
• To Luxor — the sleeper from Cairo, or a domestic flight. 6m 20s beneath an 82° Sun, over Karnak. If you are going to travel the length of Egypt, travel the length of Egypt.

Whichever you choose, arrive on 1 August at the latest. Nothing about this route survives a delayed train on the morning of the 2nd.

Weather, and why the coast is the weakest link

One more reason Alexandria is not the place to be: it has the least reliable sky in the country.

August on the Mediterranean coast is effectively rainless — rain here falls in winter — but “no rain” and “no cloud” are not the same statement. The sea breeze that makes an Alexandrian summer bearable also feeds humidity into the lower atmosphere, and coastal stratus, morning murk and high haze are all commoner here than they are 700 km up the Nile. Upper Egypt in August is one of the driest, clearest places on the planet; the Delta coast is merely quite good.

At 76° altitude the Sun is high enough that low-level haze is not a serious threat to seeing the partial phases. But the general point holds and it applies to the whole trip: every kilometre you travel south improves your odds as well as your duration. See our weather and cloud prospects page for the comparison across the country.

Alexandria in early August

• Daytime highs typically around 30–33°C — markedly cooler than Cairo or Luxor, but humid with it.
• A steady northerly sea breeze most afternoons.
• Long summer evenings on the Corniche; the city is at its most alive in August.
• Peak domestic holiday season. Alexandria fills with Egyptian visitors escaping the interior heat, and accommodation is tighter in August than at any other time of year — eclipse or no eclipse.