This now severely modified article was first published in 1998 as a response to an article in the Journal “Universe” of the Astronomical Society of New South Wales Inc. written by Greg Bryant entitled “Stars of the Southern Cross”; Universe, 45, 7 August (1998). Although the original article points out the lack of Greek lettered stars in the constellation of Crux, my aim in this one was mainly written to importantly correct some of the common factual errors and misconceptions about southern constellations. My attempt was to supply reader who might be a bit more interested in the evolution of our far southern constellations. I added it to the Southern Astronomical Delights Site, as it fits nicely into the other general articles being found here.
IT was during ancient times when the Father of Astronomy, the Nicaean-born Greek astronomer, Hipparchus (fl. c.146BC-c.127BC) first introduced the idea of assigning Greek letters in order of the brightest to faintest naked-eye stars in each constellation. Later this was also adopted by Claudius Ptolemy (fl. 2nd AD.) Such a system continues today. Customarily we often wrongly say that the German Protestant lawyer Johann Bayer (or Philolaus) (1572-1625) was the first to assign use these Greek letters to stars within the classical constellations. Such a system appeared within the 1603 original star atlas known under the shortened title just as Uranometria — from the lengthier “Uranometria : Omnium Asterismorum Continens Schemata, No a Methodo Delineata, Aereis Laminis Expressa.” It was published by Christophorus in Augsburg, Germany, under the name of the Latinised name for Bayer, Ioannis Bayeri Rhainani I.C..
Uranometria is probably more famous as it was the first detailed star atlas and was useful in identifying the stars and the outline of the constellations. Like most books of its day, the page images were fully engraved (by Alexander Mair, and includes a total of fifty-one maps. Opposing each map, the opposite page has a list of all the stars with details the Latin and Greek name of the star, if available, the main Bayer’s designation, stellar magnitude, and what part it star represents within the constellation — the latter being very similar to Ptolomy’s earlier star catalogue.
The southern stars appear at the back of the book on Map 49 with the twelve new southern constellations, followed on Maps 50 and 51 showing the whole northern and southern hemisphere, respectively. The most famous for antipodean observers is probably the engraved image of the Argo Navis — the fabled Greek ship of Jason and the Argonauts.
This is an example of Bayer’s southern map of the mega-constellation of Argo Navis. Note that the northern part of the map, including all the 1st and 2nd magnitude stars have Greek letters assigned, but those further south are simply designated ‘d’, etc. Looking at the False Cross, the stars are clear distorted when compared to how they appear in the sky today. Canopus / α Argus (now α Carina) has been placed at the stern on the waterline that guides the rudder of the fabled ship. A rock piecing out of the water conveniently hide the bow from view, which I assume might be the island occupied by the Sirens that lies according to Homer between Aeaea and the rock of Scylla in Aegean Sea. On the other side of the rock (left) is Centaurus and the Cross, marking a quite different “chapter” of the Greek stories from the Ancient world.
A few of Bayer’s original charts still do exist. Most of the information about these charts are taken from the revised edition of Uranometria published later in 1732 — a copy of which exists in the Royal Astronomical Society (R.A.S.) Library in London. These latter charts are reproductions of the originals, with little modifications or changes, and I did once inspect a set of these in England in October 1996 at an exhibition at the British Library. Both appeared more like works of art than historical astronomical documents.
Yet there are some questions about the origin of Bayer’s designations. For example, according to the author and astronomical popularist Richard Allen, in his book “Star Names: Their Lore and Meaning.” (1899), has first challenged this by saying Piccolomini of Siena adopted this same procedure some fifty years earlier. In fact, this just highlights the perpetuated misconception still frequents many familiar astronomical books.
So, although Bayer or Piccolomini did apply these letters to those to those constellations north of about −50° declination, they never assigned them Greek letters to the ‘newer’ ones in the far south. Bayer, when he did, had really 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 some significant influential force in the development of astronomy. Unfortunately, his eventual known reputation is a little shadier. Again, Richard Allen says of Bayer that he was;
We are often told that the modern constellations were passed down from ancient times, however, no direct evidence of their entire shapes or component stars truly exists today. Bayer’s important 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 entirely second or 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). Another prominent misconception example of was Bayer’s alleged discovery of the brightest globular star cluster ω Centauri. However, the true designation of this ‘hazy star’ should be Keyser and not Bayer. Simply as Bayer never labelled the object as Omega!
Although the figures are magnificent and are 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 crucifix image of 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 Roman emperor Augustus. [Book 2 : “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 could easily see both these southern constellations, so he just placed Crux into Centaurus. (Those whom own the software program Redshift 2, 3 and 4, three have these images already from Bayer’s 1732 edition of Uranometria.)
Oddly, the early Christian church remarkably never adopted Crux as their representative symbol of the worldly death of Christ. 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 formulated the labelling of the principle stars of Crux (as listed originally in Bayer’s own associated catalogue.);
| Old Crux Designations |
| α Cru [alpha]= ζ Cen [zeta] |
| β Cru [beta]= ξ Cen [xi] |
| γ Cru [gamma]= ε Cen [epsilon] |
| δ Cru [delta] = υ Cen [upsilon] |
Errors also in the drawn caricatures are appallingly inaccurate. In all, these strategically placed stars do not to match the constellation outline, but to fulfil the caricature For example, α [alpha] Centauri is placed high above the Cross, while β [beta] Centauri is on the opposite side of the cross near the current position of δ [delta] Centauri. The star ε [epsilon], however, is not drawn in the chart. As for the other new constellations of the south, Bayer added no useful lettering system. It was Jakob Bartsch (Bartschius) who published these in the “Planispaerium Stellatum” — made in the last year of Johan Bayer’s (1624) life. However, all had exactly the same stars seen in Centaurus and Crux in the original Uranometria Bayer chart.
In 1679, Augustin Royer is said to have named the constellation of Crux separately. Others have suggested it was Englishman Emeric Mollineux in 1592, though Allen says that he suspects that it origin was two hundred years before this. Royer then re-labelled the first six stars in Crux from the old Centaurus letters from; α [alpha] through ζ [zeta].
Modern Greek designations for southern constellations were again applied during the years by the French “Southern Columbus” Nicolas Louis de Lacaillé (1713-1762) after he had done his main astrometry in South Africa. In 1752 and 1753 he used a new method by using the Greek letters, and when the ran out, he just added Roman letters. Here the many large Milky Way constellations of the southern hemisphere now start an additional method applying also upper and lower case Roman letters. I.e. A to Q and a to z, but not the letters R to Z — because they were to be reserved exclusively for variable stars. He firstly applied this to the mega-constellation of Argo Navis, labelling some 180 stars, and following this same system with the constellations like Centaurus and Lupus. According to the American Benjamin Apthorp Gould (1824-1896), a grand 829 stars were visible to the naked-eye within Argo Navis, thus making up 11% of all viewable stars to the naked-eye. De Lacaillé’s adopted system was to stay in limbo for many years. Only a few of this numbering system remains, like the second brightest globular in the sky known as 47 Tucanae (NGC 104), who Lacaillé’ catalogue lists as a ‘star’. This was again succeeded with the adoption of another naming system produced by the “British Association Catalogue” (B.A.C.) in 1845.
In 1729, John Flamsteed’s (1646-1719) usage was partially superseded the exclusive use of Greek letters. He sensibly labelled all naked-eye stars that were visible from Greenwich, England by ordering them by an increasing number for each constellation. This appeared in his first star atlas, which was published after his death, along with another newer and slightly modified division of the brighter stars by Greek letters. As he could not see many southern constellations, this numbered system suddenly halts around declinations south of −30°.
Here Centaurus is the classic example of the division between northern and southern hemisphere stars. In the north, the constellation is 1,2,3,4 and 5 Centauri while in nearby constellation of Lupus, has only 1 and 2 Lupi. Yet below declination −33°, Roman letters are then exclusively applied. I.e. x Centauri and y Centauri — each positioned at the lower declination of −34°.
Overall, the many inherent problems with this random naming process is that the astronomers could never get some internationally agreed system applying to the constellations universally accepted. This made any subsequent classifications or ideas appear very arbitrary. “Miss Clerke” in “The Herschels and Modern Astronomy” properly and aptly describes it as being ; “…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 1680 and the late-1800s.
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 −55°, 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 at the lowly magnitude of 5.6v — and 10 and 13 Sagittae are both brighter! If some global application of standardised letters were placed on Sagitta, ‘Omega’ Sagitta would be below naked-eye visibility!
The real problem is systemic of the days when romantic astronomy bore some general interest to the public. Greg’s own use of the latest Hipparcos Catalogue data among the gist of the written text — just highlights the difference in our current perceptions of what astronomy is about. As a general criticism, we cannot really apply the notions of modern astronomy to the antiquated notions from the days of early observational astronomy. They are separate. (I too am equally guilty of this point, as this also appears in my other related article in UNIVERSE — See “Gacrux and the Naming of Southern Stars”)
In my own opinion, as a visual observer and part-time astrognosist (meaning essentially non-telescopic observer), that these ‘niceties’ are important — though they do not pertain at all to the modern astrophysical views of our current technologically savvy 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;
Today creating such ‘neo-formal Greek designations’ would likely more trouble than it is worth. The I.A.U. has open views on this subject, and amateurs could collectively approach the I.A.U. Commission 5 ‘Task Group on Astronomical Designations’, though your chances of success are pretty slim at best. Commission meetings are mostly scheduled every three years, next likely being August 2011.
The I.A.U. would likely disagree with us as it states in Fernandez, Lortet and Spite in “The First Dictionary of the Nomenclature of Celestial Objects” Astro.&Astrophy., 52, 4 (Section 5; Heading Number 2), where (June 1983), state; “Nomenclature based on constellation name: a (very) confusing practice.” However, if there is some general agreement approached the problem among most astronomers — amateur and professional alike, it might be possible.
Another radical approach of my own might be introducing of a Southern Flamsteed Catalogue (SFC). Here among individual southern constellations, each star in numbered based in order of increasing Right Ascension, with a limiting magnitude of 5.8v — the same as the original visual magnitude limit given by Flamsteed. Numbers already used in constellations south of -30° declination, could then be reassigned a new SFC number, and introducing these systems 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 common 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. Were such an index was applied to the southern stars, 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 astronomical 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.
