Departures of note

In the years following the 1883 explosion of the Krakatoa volcano, William Ascroft, a British landscape painter, systematically recorded the striking red sunsets over Chelsea, England. Commissioned by the Royal Academy of Arts, he produced more than 500 color sketches of these twilight skies, capturing details that would otherwise have been lost before the invention of color photography.

Ascroft was known for his regular habit of sketching the sky at sunset, a practice that proved invaluable in documenting the atmospheric effects of the volcanic eruption. His works remained a visual record of the phenomenon for over a century.

In 2010, John Rowlands, a Welsh astronomy author and observer, identified several of Ascroft's post-sunset sketches as indisputable depictions of noctilucent clouds—a twilight phenomenon of the mesosphere. Rowlands suggested that these clouds likely became more common following the Krakatoa eruption, and that continued industrial emissions later made them a predictable, repeating summer phenomenon.

Ascroft's sketches thus serve not only as artistic works but also as scientific evidence, bridging the gap between art and atmospheric observation in the late 19th century.