Events · August 13, 2026

The Perseids After the Peak: Six Nights That Still Work

The maximum fell on the night of 12 to 13 August, under a Moon-free sky, and a great many people missed it: clouds, or simply going to bed. The good news is that a peak is not a door closing. The Perseid stream is active from 17 July to 24 August according to the International Meteor Organization’s calendar, and on two counts the geometry of the following nights is better than that of the peak itself.

The first point is routinely ignored: from western Europe, the Perseid radiant never sets. It sits at 3 h 13 min of right ascension and +58° of declination, and any declination above 41.1° is circumpolar at the latitude of Paris. There is therefore no hour of the night at which the shower is out of play. There are only hours at which it is too low to be worth your time.

Why the stream does not stop on 13 August

A meteor shower is not an event, it is a crossing. Earth takes more than five weeks to pass through the ribbon of dust laid down by comet 109P/Swift-Tuttle, and the maximum marks nothing but the densest stretch of it. On either side the rate falls off, quickly, but it does not drop to zero from one evening to the next.

We are not publishing a decay curve: the real rate on the night after a peak depends on the fine structure of the ribbon, and that is measured afterwards, not calculated in advance. What we can calculate are the two factors that decide everything else: the altitude of the radiant, and the Moon.

The six nights that are left

Night by night, computed for Paris: the window of astronomical night (Sun below −18°, the only regime in which the sky background stops being lit), the altitude of the radiant at 2 a.m., the illuminated fraction of the Moon at the same instant, and the time it leaves the sky.

The column that decides everything is the last one. Up to and including 18 August, the Moon sets before astronomical night begins: 22:52 at the latest on the 18th, against a true night that opens at 23:06. Which means the six nights from the 13th to the 18th hand you the whole of their astronomical night without a gram of moonlight in it. Five and a half hours of full dark, every night.

On 19 August the Moon takes the sky back

The turn is sharp and it has a date. On the night of the 19th to the 20th the Moon sets at 23:17, sixteen minutes after astronomical night begins: the overlap starts. The following night it is forty-eight minutes, and from the 21st a two-thirds lit Moon holds the sky until 00:28. On 24 August, the last day of the stream’s activity, it shines at 90 % until 03:30 in the morning: barely an hour of real night is left before dawn, and only the brightest trails will survive it.

So this is a window with a short shelf life. If you are only going out once, go out before the 19th.

The radiant climbs, and that is pure gain

The second factor works the other way, in your favour. A low radiant delivers only a sin(h) fraction of its rate: at 26° of altitude you are capped at 44 % of what the same stream would give overhead. And the radiant climbs all night, a little higher with each night that passes.

On the night of the 13th to the 14th it stands at 26.5° when astronomical night opens, 42.7° at 2 a.m., and 61.9° at the astronomical dawn of 04:30. Eleven nights later, at the same markers, it will have gained one degree at the start and nine at the end. The practical conclusion does not move an inch: the best hour is the last one, between 3 a.m. and dawn.

And the aiming advice is the same as on peak night: do not stare at the radiant. Trails seen there are foreshortened, therefore short. Look 30 or 40° to one side, lying down, and let your peripheral vision do the work. To find exactly where it stands at the hour you step outside, the SkyChart sky map puts it at its computed position, between Perseus and the W of Cassiopeia.

What will actually decide your night

Neither the radiant nor the Moon is your first enemy: it is the glow over your own town. A meteor shower is a faint-magnitude spectacle, and faint magnitudes are precisely what light pollution erases first. Between a class 9 sky and a class 4 sky the difference is not « a few meteors fewer », it is an order of magnitude, as we measured in our article on the Bortle scale. Thirty minutes of driving usually beats an hour of patience.

The limits of these figures

The times, altitudes and phases are geometric: they are exact, and they contain no weather whatsoever. The reference zenithal hourly rate of 100 published by the IMO is a catalogue value, not a forecast for a given night, and in any case it only holds for a sky of limiting magnitude 6.5 with the radiant overhead, two conditions no observer in western Europe meets this month. Finally, the times are computed for Paris: the further west you stand, the later true night begins, by roughly four minutes per degree of longitude.

Source for the stream’s activity period: the International Meteor Organization Meteor Shower Calendar. Everything else is computed by the SkyChart ephemeris engine.

• Perseids
• August 2026 sky