Minimal Astronomy

When we imagine early astronomy from ancient times to the medieval we assume that lacking optical devices they would see only pinpoints of light fixed in their place all eternity. Sure they would have noticed that the Sun and Moon moved across that backdrop, and these stars would make interesting patterns, but that’s about all the naked eye could show you, after all we wouldn’t see much more today.

Then I realised that until relatively recently the skies were really dark. Consequently the night sky would have been far more dramatic and dynamic to the ancient eye than it is to our own. Modern skies are so bright that it’s easy to fail to notice there’s anything up there at all, and most don’t even bother to look.

The Sun and Moon are bright enough to be seen in the most light polluted sky, but the planets all the way out to Saturn are bright enough to be easily visible to your eyes, and although their true nature might not have been known they were named and their strange paths commented upon: these were not normal stars!

The rugged bright band of the Milky Way moves across the sky with the seasons being right overhead in the late summer and autumn at mid-northern latitudes. In the dark it casts a shadow so I’m told and is a mosaic of dense starlight and dark dust clouds.

They certainly noticed that the patterns of stars that give rise to the constellations also move throughout the year and gave many of them names. The fact they managed to pick these stars out of the dazzling background shows that they were really observing. Several stars were singled out as having special significance in connection with seasons.

To cap it all some of the “unchanging stars” were seen to vary in brightness, such as Algol (beta Persei), and new stars would very occasionally appear in a dazzling flash that would become known as Novae or Supernovae, such as that which created the Crab Nebula.

Comets would have been more noticeable and invested with the power of victory or doom. I can only imagine how spectacular the regular meteor showers would have appeared.

I would love to experience those skies, but I really don’t like to travel and few places in the World remain where you can see what the ancients might have. All the same much of what I’ve mentioned is available in a diluted version to modern unaided eyes (well perhaps with glasses).

I’d urge you to try really observing the Moon and see what you notice; have a go at making brightness estimates for variable stars like Algol; try splitting some wide double stars and see what’s the closest you can manage; and examine the large scale structure of the Milky Way. You don’t need any equipment to be an amateur astronomer.

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