Exploding Meteor in a Milky Way Time-Lapse: Wes Eisenhauer, South Dakota

On the night of 16 October 2014, photographer Wes Eisenhauer was shooting a Milky Way time-lapse outside Custer, South Dakota, when a meteor exploded in the frame. Its glowing trail lingered in the sky for several minutes and twisted in the upper-atmosphere winds, a rare event called a persistent train.

Eisenhauer noticed movement at the edge of his vision while the camera was running. When he played back the footage, he found what he titled Meteor explosion Milky Way Time Lapse. Space and astronomy sites, from Universe Today to the American Meteor Society, featured the clip within weeks.

How the Milky Way time-lapse was shot

The kit and settings are listed with the video:

• Canon 5D Mark II with a 16–35 mm lens on a Manfrotto tripod;
• a Vello Shutterboss intervalometer to fire the shutter automatically;
• 120 consecutive exposures of 30 seconds each, at f/2.8 and ISO 5000.

That adds up to about an hour of sky squeezed into a few seconds of playback. The trail the meteor left behind lasted several minutes in reality, yet on screen it seems to writhe and fade in moments. That is why the “four seconds” in many headlines is a playback mark, not the length of the event.

What is a persistent meteor train?

A fireball is a very bright meteor, brighter than about magnitude −4, roughly as bright as Venus. A fireball that ends in a sudden terminal flash, often breaking apart, is called a bolide. As a meteoroid tears through the upper atmosphere it ionises the surrounding air. When electrons recombine with atoms, the air glows, leaving a luminous trail.

Astronomer Phil Plait put it simply: “Technically, that’s called a persistent train, and it’s not actually smoke.” According to the American Meteor Society, these glowing trains of ionised air generally form above 80 km. Most last only a few seconds, but rarely one survives for several minutes, and winds at around 100 km of altitude bend it into loops and spirals. That is the slow, twisting shape visible in Eisenhauer’s footage.

Was it an Orionid meteor?

Mid-October is close to the Orionid meteor shower, but Universe Today noted that the footage was taken before the shower officially began. It was more likely a random, larger-than-usual meteor. Several thousand fireball-class meteors enter Earth’s atmosphere every day. Most fall over oceans or empty land, or in daylight. An experienced observer sees a magnitude −4 fireball roughly once every 20 hours of watching, so catching one on camera with a lingering train is a real piece of luck.

Tips for night-sky photography and reporting a fireball

• Find dark skies. Rural areas far from city glow, like the Black Hills around Custer, show the Milky Way best.
• Shoot wide and fast. A wide lens at f/2.8 and high ISO, with 20–30 second exposures, captures faint stars before they trail.
• Keep every frame. Save the raw sequence as well as the edit; a surprise like this one often appears only on playback.
• Report what you see. The American Meteor Society collects fireball reports at fireball.amsmeteors.org. Note the time, brightness, colour, duration, and start and end points against the constellations.

Compare the compressed time of a time-lapse with Kwon O Chul’s real-time aurora film. For still images of the night, explore Mikko Lagerstedt’s night photographs.

Related reading

• Vincent Brady’s Toroidal Sky: A Four-Camera Night-Sky Experiment
• Kaspars Daleckis’s Latvian Aurora Time-Lapse
• Sun Halos over Finland: Understanding Pauli Hänninen’s Photographs
• Vincent Brady’s Planetary Panoramas
• Mike Taylor’s Maine Aurora Photography and a Change of Direction
• Thierry Cohen’s Darkened Cities: Imagining Urban Skies Without Light Pollution
• Thomas O’Brien’s Meteor-Shower Time-Lapse Around Aspen
• The Mountain: Seven Days of Sky Photography at Teide

Sources