By Andrew James

In ancient times, Hipparchus (fl.c.146BC-c.127BC) first introduced Greek letters for the brightest to faintest stars, later adopted by Ptolemy (fl.2nd AD.). Traditionally, we say that the use of Greek letters in the constellations was first made by the German protestant lawyer, Johann Bayer (or Philolaus) (1572-1625). Here, within the 1603 original star atlas known as Uranometria, Bayer is said to have applied Greek letters for each star within a constellation. Richard Allen in 'Star Names: Their Lore and Meaning.' (1899) has challenged this by saying Piccolomini of Siena adopted this procedure some fifty years earlier. In fact, this is a misconception, that is perpetuated in most of the astronomical books. He did apply these to those constellations north of c.-50o declination, but never assigned them Greek letters to the ‘newer’ ones in the far south. Bayer had adopted only the designs from several engravings made by Albrecht Dürer (1471-1528) in 1515.

Modern writers often place Bayer on a high pedestal, venerating him as a significant force in the development of astronomy. Unfortunately, his true reputation is a little more shaded. Again Richard Allen says of Bayer that he was "“...a poor and inexact cartographer”" and “...a work much tinctured with the occult science.”

We are often told that the constellations were passed down from ancient times, however, no direct evidence of their shapes or component stars truly exists today. Bayer's main contribution was simply to attempt to reapply ancient lore with the visible night sky. In regards the shaping of the constellations and the designing the newer southern ones, Bayer never created nor observed them - all he did was exclusively apply his imagination to the assumed names. The southern skies were different, as his knowledge was either second or entirely third hand. Conversely, Bayer had no problems with the northern stars, as all he had to do was literally walk out the backdoor and look up. Southern positional observations and descriptions used in the original Uranometria were exclusively made by the Dutch southern explorer Pieter Dirckz Keyser (Pieter Theodori) (?-1596). As such, the prominent example of Bayer’s discovery of Omega Centauri as we should accredit a ‘hazy star’ to Keyser not Bayer. [Note: Bayer never labelled it Omega!]

A few of Bayer’s original charts still exist. Most of the information about these charts usually is stated from a revised Uranometria published later in 1732 - a copy of which exists in the Royal Astronomical Library in London. These latter charts are reproductions of the originals, with little modifications or changes. I inspected a set of these in England in October 1996 at an exhibition at the British Library. Both appear more like 'works of art' than historical astronomical documents.

Although the figures are magnificently and skilfully drawn, the stellar positions are far from perfect. An example is the area of Crux and Centaurus. In the 15th Century, Crux was a sub-constellation of Centaurus - existing only as a mere asterism. The image portrayed is of the centaur Chiron (or Chyron) viciously spearing Lupus the Wolf. At the rear of the hind legs is the image of a crucifix - the asterism known as 'Thonis Caesaris (or Thronos Caesaris), named by the ancient historian Pliny the Elder (or Gaius Plinius Secundus Pliny) (23AD-79AD) in honour of the emperor Augustus. [Book 2 in his “Natural History”] Crux then was visible on the southern horizon from Rome during April and May, though due to the precession of the equinoxes it is not visible there today. Ptolemy also placed Crux into Centaurus, and he was much better placed to see both constellations to the south. (Those whom own the software program Redshift 2 to 4 3 have these images already from Bayer’s 1732 edition of Uranometria.) Incidentally, the early Christian church remarkably never adopted Crux as a representative symbol of Christ's worldly death. From the 13th Century seafaring explorers south the equator held some romanticism with Crux - deifying these stars by reinforcing their Christian faith against the fear of the unknown. Bayer first formulated the labelling of the stars of Crux as [epsilon], [zeta], [upsilon] and [xi]; [alpha]= [zeta], [beta]= [xi], [gamma] = [epsilon] and [delta] = [upsilon], as listed in Bayer's attached catalogue. Errors in the drawn caricatures are appallingly inaccurate. In all, these stars are strategically placed not to match the constellation outline, but to fulfill the caricature. For example, [alpha] Centauri is placed high above the Cross, while [beta] Centauri is on the opposite side of the cross near the current position of [delta] Centauri. The star [epsilon], however, is not drawn in the chart. As for the other new constellations of the south, Bayer added no lettering system. Jakob Bartsch (Bartschius) published these in the last year of Bayer's life (1624) in 'Planispaerium Stellatum'. - but had all the same stars seen in Centaurus and Crux in Bayer's original.

In 1679, Augustin Royer is said to have named Crux a separate constellation. Others have suggested it was the Englishman Emeric Mollineux in 1592, though Allen says that he suspects that it origin was two hundred years before this. The 'serious-minded' John Flamsteed (1646-1719) in his first star atlas post-humourously published a new division of the brighter stars by Greek letters. He labelled the first six stars in Crux as [alpha] through [zeta]. Most of the modern Greek designations for southern constellations were applied during the years 1752 and 1753 by the French 'Southern Columbus' Nicolas Louis de Lacaillé (1713-1762). de Lacaille's used new method by following the Greek letters with Roman ones. Here the large Milky Way constellations of the southern hemisphere starts an additional method applying upper and lower Roman letters. Ie. A to Q and a to z, but not the letters' R to Z, because they are reserved exclusively for variable stars. He firstly applied this to the mega-constellation of Argo, labelling 180 stars, then followed this with Centaurus and Lupus. (According to the American Benjamin Apthorp Gould (1824-1896), a grand total of 829 stars were visible to the naked eye in Argo. (11% of all the stars visible to the naked-eye.)) de Lacaille's system was held in limbo for many years, with the adoption of the naming system by the 'British Association Catalogue' (B.A.C.) in 1845.

Flamsteed partially superceded the use of Greek letters in 1729, who sensibly labelled naked-eye constellation stars by ordering them by an increasing number for each constellation. As he could not see many southern constellations, this numbered system suddenly halts south of declination c.-30o. Centaurus is agin a classic example. In the north of the constellation is 2, 3, 4 and 5 Centauri and in nearby constellation of Lupus, 1 and 2 Lupii . Yet below declination -33o, Roman letters are exclusively applied. ie. x Centauri and y Centauri at declination -34o.

Overall, the inherent problem with this random process of naming is that the astronomers could never internationally agreed upon the constellations. This made any subsequent classifications appear very arbitrary. "Miss Clerke" in "The Herschels and Modern Astronomy" aptly describes it as; "...a system of derangement and confusion." They did not achieve ratification of the eighty-eight constellations until 1930, when the International Astronomical Union finally agreed on them. This 'convoluted mess' in labelling of Greek letters (and Roman letters) for southern stars was added literally 'ad-hoc' between c.1680 and the late-1800's.

Only certain constellations have stars with Greek letters that are below 5th magnitude, while others even above 3rd are ignored. It is likely that they make the labelling systems simply to define the outline of the constellation and were never properly or logically organised based on stellar magnitudes. South of declination -55o, the number of Greek letters does not correlate with magnitude but the area of each individual constellation. For example, the similar sized northern constellation of Sagitta has the same problems as Greg suggests for Crux. Here the lowest Greek letter is Zeta (ζ), although Epsilon (ε)is a lowly magnitude 5.6 - and 10 and 13 Sagittae are both brighter! If a global application of some standardised letters were placed on Sagitta, 'Omega' Sagitta would be below naked-eye visibility!

The problem is systematic of the days when ‘romantic’ astronomy bore some general interest to the public. Greg’s use of the latest Hipparchus Catalogue data among the gist of the written text - highlights the difference in our current perceptions of what astronomy is about. As a general criticism we cannot apply the notions of modern astronomy to the antiquated notions from the days of early observational astronomy. They are separate. (I am equally guilty of this point, as in my article in UNIVERSE on the “Gacrux and the Naming of Southern Stars”) I am of the opinion, as an observer and a part-time astrognosist (meaning a non-telescopic observer), that these ‘niceties’ are important - though they do not pertain to the modern astrophysical view of astronomy.

Changes to constellation names and designations are not new. Sir John Herschel and Francis Baily in 1841 suggested a reformation in the naming and assignment of Greek letters to the Royal Astronomical Society. It did not work. As Richard Allen says; “...their changes were too sweeping and were not successful...

Today creating ‘neo-formal Greek designations’ would likely more trouble than it is worth. The IAU has open views on this subject, and amateurs could approach IAU Commission 5 ‘Task Group on Astronomical Designations’, though your chances of success are pretty slim. Commission meetings are scheduled every three years, next likely being August 2000. The IAU would likely disagree with us as it states in in (Section 5; Heading Number 2) Astro.& Astrophyh., 52, 4 “The First Dictionary of the Nomenclature of Celestial Objects”. where Fernandez, Lortet and Spite. (June 1983), state; "Nomenclature based on constellation name: a (very) confusing practice." However, if a general agreement approached the problem among most astronomers - amateur and professional alike, it might be possible.

Another radical approach maybe a Southern Flamsteed Catalogue (SFC) where the southern constellations are assigned a number, numerically based on increasing right ascension. Here each constellation would be numbered based on the Flamsteed magnitude limit of 5.8. Numbers already used in constellations south of -30o declination, could then be reassigned a new SFC number. Introducing these system could be made fair quickly, and would apply to about 1 800 stars. The largest number would be about 230 in the constellation of Centaurus. One minor problem is the 1725 epoch used by Flamsteed has meant that the proper motions have begun to mix up these numbers. For example, 20,21,22,23 Herculis has been now reordered in Right Ascension as 22, 20, 23, 21 Herculis. If a such an index to the southern stars is applied, should it be the 1725 epoch or 2000 epoch?

Furthermore, the overall consequences would definitely affect the modern celestial cartographers, as all atlases and most astro-software would need updating. If we truly adopted such a system, Epoch 2050.0 star atlases could possibly adopt such changes. Do amateurs need such identification? I leave that to you.

As Dante’s final sentence in ‘Inferno’ aptly states;

Thence we came forth to rebehold the stars

I’ll say no more.

Note: Greg Bryant’s article “Stars of the Southern Cross”(UNIVERSE, 45, 7 August (1998) points out the lack of Greek lettered stars in the constellation of Crux. I thought our readers maybe a bit more interested in the evolution of the far southern constellations.


Last Update : 29th October 2005

Southern Astronomical Delights © (2005)


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