Last night’s eclipse was spectacular. The reddening moon hung below Regulus (the brightest star in Leo) and next to Saturn.

It was the twenty-sixth eclipse of Saros Cycle 133, which began with the lunar eclipse of May 13th, 1557, and will end with the eclipse of June 29th, 2918. Each Saros Cycle comprises eclipses with very similar geometries and approximate periodicity of 18 years, 11 days and 8 hours. There are currently forty-one different active lunar Saros Cycles.

Babylonian astronomy had become quite sophisticated by the time of the reign of Nabonassar (747-733 BCE), and the Saros Cycle was well understood by Babylonian astronomer-priests by the sixth century BCE. Lacking knowledge of the true geometry of the solar system (or so we presume), the Babylonians kept records of the observable circumstances of lunar and solar eclipses beginning perhaps as far back as the eighteenth century BCE and eventually gleaned their hidden patterns of recurrence. Ancient Babylon is present day Iraq.

This picture is a composite of three bracketed shots, layered together in Photoshop. I took it with a Nikon D80. It was attached by a t-connector to a TeleVue Pronto telescope - effectively a 480mm (equivalent to 720mm on a 35mm camera), f6.8 telephoto lens.

As I reluctantly left the house on this 4° F morning, the first sound I heard was the distinctive song of the Northern Cardinal shown here, perched on a bare branch of my neighbor’s maple tree. Why do they stay here in winter? Not only here; cardinals are year-round residents as far north as upper Michigan and southern Ontario.

Birds have a varied arsenal of defenses for coping with the cold, honed by the benevolent hand of adaptive evolution via the mechanism of natural selection. Feathers can be fluffed, creating pockets of air that protect a bird’s skin from heat loss. Many species of birds have circulatory systems that can greatly reduce the loss of heat through their unprotected feet and legs in cold weather by strategic narrowing and expansion of their arteries and veins. Some birds have the extraordinary ability to let their body temperature fall precipitously — lethal hypothermia in human talk — and bring it back up when conditions permit.

But cardinals don’t do the hypothermia trick, so the question persists. Why do they stay here in winter?