Red flashes beyond La Silla
Processed image. Panorama and six enlarged exposures from 20 January 2015. Labels run from 07:22:17 to 08:04:16 UT: separate flashes, not one continuous event. Stars, airglow and observatory provide context. WebP conversion retains the full framing and clock labels.
CC BY 4.0
· Original image source · Image licenceFind the small red tendrils near the horizon, then compare the enlarged panels. What connects the photographs with a distant storm?
- World
- Earth
- Location
- Chile
- Case date or period
- 20 January 2015
Look beyond the Milky Way
Find the red structures near the horizon, then inspect the enlarged panels. ESO combines a La Silla panorama with six sprite views. The presentation preserves their surrounding sky while making faint details easier to see. It is a published composite, rather than a continuous movie or one simultaneous configuration of every flash.
An observer notices brief red light
Horálek was photographing the Milky Way on 20 January 2015 when brief red flashes caught his attention. His camera’s infrared-blocking filter had been removed to improve its response. The later observer-led account documents that instrument history. Increased sensitivity helps explain the successful capture; the photographs do not provide a calibrated spectrum or an individually measured sprite altitude.
The storm was far from the camera
Horálek and his co-authors associated the display with thunderstorms over northern Argentina. Their Meteosat-10 weather image, taken at 07:30 UTC that day, placed the storm core about 560 kilometres from La Silla. This combines ground photography with a separate satellite observation. It identifies a likely weather system rather than triangulating every discharge. The camera’s Chilean observatory and the distant Argentine storm are different locations in the story.
Several flashes across a longer interval
ESO describes a display lasting roughly forty minutes, with individual sprites lasting fractions of a second. The enlarged panels therefore do not show a persistent object. Their labels allow the separate recorded appearances to be compared. The subsequent Paranal observation belongs to another night and is excluded here.
Colour gives context, not a spectrum
ESO’s explanatory account connects the red light with excited atmospheric nitrogen and describes electrical structures with beads, puffs and tendrils. Compare those descriptions with the visible shapes. This supplies a physical explanation for the phenomenon class; it is not a chemical measurement of these exposures. The same distinction applies to general altitude ranges, which cannot become measured heights for individual photographed sprites.
What the photograph leaves to investigate
Dim flashes lasting fractions of a second are difficult to record. The successful photographs let us examine structures that a casual glance might miss. They also leave a useful next step: matching each exposure to its triggering lightning stroke. The photographs, weather association and physical explanation work together, while questions about the electrical timing and geometry remain open.