Excellent. I was teaching physics (secondary school) at the time and got my students to read it. Resulted in some interesting discussion

A very long time since I read it (1984/5), so can’t remember much about it!

Also "The Planiverse: Computer Contact with a Two-Dimensional World" A K Dewdney (1984)

Passage of light through hexagonal ice crystal that gives rise to circumzenithal arc involves two refractions whereas that through a drop of water involves two refractions & one reflection. The colours of Cz Arc are better separated (i.e purer) than those of a rainbow

Strangely there is no specific term for the brightness within the primary arc, though there is one for the reduction in brightness between primary & secondary despite not always being evident: Alexander’s dark band. (Alexander of Aphrodias 2nd century AD)

The corona around the moon is visible in the reflection in the river but not around the moon itself. This not uncommon because reflections are less bright making it easier to see/ photograph

Is anyone's? The extent of the "known world" according to 15th C Europeans is as much evidence of their inquisitiveness as it is of their desire to enrich themselves through trade. I believe that the Mesoamericans were unaware of the islands of the Caribbean.

In his correspondence he emerges as a remarkably likable and well balanced man. Described as “in his person he was of a middle stature, inclining to tallness, of a thin habit of body, and a fair complexion, and always spoke as well as acted with an uncommon degree of sprightliness and vivacity.”

But did they know about one another. As far as I know, they did not even through they shared landmass. Make of that what you will

Initiated by Faraday in 1825

A close friend noted that “…his mind could never bear to pass up any phenomenon without satisfying itself at least of its general nature and causes.” Among those was that of colour vision. Independently of Helmholtz, he proved there are 3 types of cone cells and measured their relative sensitivity.

Helmholtz was indirectly responsible for obtaining proof of Maxwell's em waves by inspiring Hertz's experiment that created radio waves. Curiously, M. never sought such proof, though as head of the Cavendish lab, he had the means to do so.

Thomas Young who got the ball rolling with his double slit expt, & Faraday with his 1846 suggestion that light might be an electromagnetic wave both deserve a place in the this pantheon.

Keats famously-and mistakenly-accused science of consigning the rainbow to the “dull catalogue of common things” and of stripping it of wonder. He had Newton in mind, I suspect. Ruskin was of the same mind: “For most men, an ignorant enjoyment is better than an informed one…" Mod Paints v3

Discovery favors the prepared mind and you knew they were worth a second look!

It’s not just cars at night. I was left with an after image that lasted a couple of minutes when I inadvertently glanced at the bright led bike light of an electric bike mid morning on a sunny day.

Together with the eye catching sun dog images you posted, what a great start to your day. Only wisps of cirrus here in Wimbledon this am

Austria scrawny eagle looks as if has been through a hedge backwards