Eclipse glasses for a summer camp or summer school: one per child, one per leader, plus spares

One per child, one per leader and a few spares: with 40 children and 6 leaders, 46 pairs plus the reserve ones. On Monday 2 August 2027 there’s no school, but there are summer camps, summer schools and sports camps, and the morning is long: in Tarifa, the Moon starts covering the Sun at 09:40:56 and doesn’t let go until 12:00:35. That’s more than two hours with children, August sun and glasses. All times are mainland Spanish time (CEST, UTC+2).

How many: the sums

The AAS (American Astronomical Society) says that a large group can share a few pairs of glasses, because the partial phase moves slowly and an occasional look is enough. With children, we wouldn’t. The AAS itself asks adults to supervise children using solar filters at all times, and with shared glasses, whoever is waiting their turn does so with the Sun in front of them and nothing on. The leader also watches and has to check everyone else’s glasses, so the sum is children plus leaders plus spares.

You need spares because the AAS says to throw away any scratched, punctured or torn filter, and at a camp some pair will get bent, wet or trodden on. With one spare in ten, rounding up (an example):

If you’re going to do the paper-plate trick, each pair stays stuck to its plate and can’t be lent out any more.

Sizes, plates and names

On a small face, adult glasses leave gaps at the sides. The family guide (in Spanish) explains children’s frames and the elastic band trick. The plate trick, which NASA and the American Academy of Pediatrics suggest for the youngest children, is explained step by step in eclipse glasses for children. If the children make the plates themselves, NASA’s lesson plan asks the teacher to check each pair to make sure it is firmly stuck; at a camp, that job falls to the leader. Writing each child’s name on the cardboard, never on the filter, stops pairs getting swapped.

How many adults

On this website we argue for one adult for each young child (in Spanish) while the Sun is in view. A camp doesn’t have that ratio, so the way to get closer to it is to split up the morning: while most of the group does activities that don’t involve looking at the Sun, a leader goes out with a small group to look through glasses for a couple of minutes and comes back. It’s one way of organising things, not a rule.

The morning, town by town

The partial phase has two long stretches, before and after totality. In Tarifa they last 1 h 04 min before and 1 h 11 min after, according to our contact times. Some examples (mainland times; totality from the IGN, Spain’s National Geographic Institute):

Your own town’s times, with the moment of maximum eclipse, are on what time is the eclipse.

What to do during the partial phase

Children aren’t going to look at the Sun for two hours, and there’s no need for them to. What works is whatever you can do without looking at it:

• Project it with a colander, a box with a hole in it or the shade of a tree: it’s all in the homemade viewer (in Spanish).
• Measure the temperature every ten minutes and write it down, to see what happens: how much does the temperature drop during an eclipse.
• Draw the phases or explain why it happens: explaining the eclipse to children.
• Look through the glasses now and then, in groups and with their leader. That’s what the AAS suggests for a group: a glance every few minutes is enough to see the Moon move along.

When to take them off

Inside the path, glasses come off only during totality and at the leader’s signal, and the leader must know the exact second for their town: it’s in when to take off eclipse glasses in totality. Outside the 105 towns with totality, as in Granada or Seville, they stay on all morning.

Shade, water and the August sun

At the time of maximum eclipse, the Sun will be high, between 34.5° and 47.6° above the horizon depending on where you are on the mainland, and still climbing. Waiting in the shade and going out to look in turns works well with the heat: cap, water, sun cream and the group together.

On Order your glasses you can ask for ours: cardboard, with the EN ISO 12312-2 certificate, along with the phone filter and packs for groups. We reply with the price and the delivery time.

Sources: AAS — How to View a Solar Eclipse Safely (a group can share a few glasses; a glance every few minutes; always supervise children; discard a damaged filter); NASA, My NASA Data — Solar Eclipse Safety Activity (the plate for young children; the teacher checks each pair); start, end and contact times, and the Sun’s altitude: eclipseando data (skyfield engine + DE440s); totality durations: IGN.