V · Report and join
Report a halo
Tell us what you saw. We reply with the name of every arc and the Sun’s height at the minute you saw it. Sending a report makes you a member; it costs nothing.
What to write down
Five things we need
- WhenThe date and the time, to the minute if you can. The arcs move with the Sun, so the minute matters.
- WhereThe town or the nearest place with a name. We work out the Sun’s height from it.
- WhatRings, bright patches, arcs, a pillar. Which side of the Sun, above or below.
- How farIn hands at arm’s length if you had nothing else. One hand is about 22°.
- How longWhen it appeared and when it faded. The 1535 display over Stockholm lasted two hours.
After you send it
Within a week, a reply
Two of us read every report. We work out the Sun’s height for your place and minute, name each arc you describe, and say which crystals made it.
Every 20 April we meet at 10:00 at Storkyrkan, in front of the 1636 copy of Vädersolstavlan, then walk to Södermalm, where its painter looked at the sky. Members bring their year’s best report.
Questions
Before you write
Often, not always. The thin cirrostratus that makes halos can run ahead of a warm front, so rain may follow within a day; but the same cloud also comes and goes with no change in the weather.
No. Rainbows come from water drops. Halos come from ice crystals, and sit around the Sun, overhead or level with it. A corona, the small coloured disc right round the Sun or Moon, comes from water droplets too.
It needs the Sun at 58° or higher. North of 55° the Sun never gets that high, and Stockholm is at 59°. London gets about 140 hours a year of it.
Yes. Send it as it came from the phone: the time stored in it helps us work out the Sun’s height.
