Tuesday, August 24, 2010

Where did all Bayer's letters go?

Johann Bayer published his celebrated Uranometria atlas in 1603, and it's from there that we get many of the Greek designations, such as Alpha Centauri. But did you know that, when he'd exhausted all 24 letters of the Greek alphabet, he assigned stars Roman letters?

He started with A (because a could easily be confused with α), and the proceeded from b, down the lower-case alphabet, only ocasionally getting into the 2nd half of the alphabet. It's where we get names such as h Persei, p Eridani and so on.

But have you noticed that they've been disappearing over the past thirty years?

In 1979, Dorrit Hoffleit (astronomer at Yale University) in her paper, "Discordances in Star Designations", pleaded that all roman letters, other than that for Variable stars, be excluded from future catalogues. When she released the 5th edition of the Bright Star Catalogue, that's exactly what she did. The letters were gone. In the popular Sky Catalogue 2000.0 (1982), all but a few Bayer letters were expunged.

But not everyone wants to lose these designations and be forced to use cumbersome catalogue numbers for these stars. Atlases continue to use them, and Morgan Wagman, in his book Lost Stars, goes as far as saying that this practice is patently unfair and discriminatory against stars with Roman letters.

I have sympathies both ways. Without roman letters, many stars remain unlettered, and we're forced to use long catalogue numbers. This is particularly so in the Southern Hemisphere (until we make better use of Gould Numbers). We need further simple designations to use. But I also understand the other side of the argument. Many of the lower-case Roman letters are frequently confused with the Greek ones, meaning that most atlases and catalogues over the past fifty years have multiple errors.

What's the solution? Should we restore them or not? Or should we make some sort of compromise?

1 comment:

  1. Anonymous07 July, 2011

    I agree that they should be restored, for historical reasons. The BSC does not form a complete superset of Bayer's designations, nor Flamsteed's, and certainly not Gould's. Having fully fleshed out Bayer-style designations for the entire sky, with a predefined, modern magnitude cutoff (of approximately 6.5 or 7.0) would be a great start. Of course, that would probably require dipping fairly deeply into the pool of letters for larger and/or denser constellations. Such issues could be addressed by the Flamsteed and Gould designations, but they, too, fall a bit short of completeness in places.