Seeing astronomical events

A total solar eclipse is an amazing spectacle.  You might not even notice other astronomical events.

In a few weeks the US will be treated to a total solar eclipse.  It is a spectacular thing to see and our astronomer urges everyone to get to the path of totality if they can.  Well, maybe not everyone; someone must keep the rest of the country ticking over.  So for the rest of the population, and for other days, what about other astronomical spectacles?

The unfortunate fact is that, while a total solar eclipse will get your attention even if you aren’t looking for it, most modern people would not notice anything else in the astronomical sky.  This seems a strange thing to say, when fantastic images from astronomers appear regularly in news media, but it’s true.

What about those pictures of planets?  Wonderful swirling clouds on Jupiter, the rings of Saturn, the deserts of Mars?  They come from space probes in orbit or on the surface of those places, and they’re very far from here.  While planets are often among the brightest “stars” in the sky, a view through any Earthbound telescope is likely to be disappointing.  Invariably, when our astronomer shows Saturn to a member of the public through a telescope, the reaction is, “It’s so small!”  Which is true; the planet covers a small fraction of a degree as seen from Earth.

What about those ominous portents, comets?  The seemed to scare people badly enough in the old days.  Well, at any moment there are several visible in the sky–if you have a telescope.  Most comets are faint.  Those you can even see with your naked eye are rare; those that can compete with artificial lighting, even more so.  The very brightest of comets cannot compare to a streetlight a block away.  Similarly, “meteor showers” mean one visible (mostly faint) meteor every few minutes.  With one or two rare exceptions, there is no rain of stars from the sky.

The most prominent astronomical event, after a total solar eclipse, is a total lunar eclipse.  The Moon goes from a brilliant Full stage to a dark, reddish object (the picture at the beginning of this post shows an eclipsed Moon).  Stars that were flooded out by moonlight become visible.  If you are looking for it, and if you are familiar with how the Moon normally appears, it’s spectacular.  If you aren’t, you might notice that the Moon looks strangely dark and red, or you might not.

For the next solar eclipse, many people will not be able to get to the path of totality, and will be able to see only a partial eclipse of the Sun.  It will be hard to notice.  Even when the Sun is 90% covered by the Moon it looks like daytime outside; the light may seem a little strange (appearing as if the landscape is under water), but not even as dark as a thick overcast.  You’ll only notice that the Sun is the wrong shape (DON’T LOOK AT THE SUN WITHOUT A PROPER FILTER!), and then only if you know it should be quite round.  If you have a tree where the Sun shines through gaps in the leaves, normally forming round blobs of light, those blobs will turn into crescents.  (That’s probably worth a picture.)

Astronomical events are noticeable, even spectacular, only when you are familiar with how the sky routinely appears.  Alternatively, like our ancestors you could spend much time outside under a dark sky.  But then the sky itself becomes rather spectacular.