Reflections on the Star of Bethlehem at Christmas 2005


At Christmas 2005 Venus has been beautifully placed, low in the evening sky bringing with it obvious thoughts of the Star of Bethlehem. These have not been reduced in my mind by the usual round of Christmas talks and interviews about the Star, which have included a Christmas debate in Bristol about the Star of Bethlehem, moderated by the Rev. David Lloyd (Vicar of Henbury), where I argued the case for the 5BC nova and my opponent, Rod Jenkins (a retired engineer who worked on the Giotto probe), argued that the Star was a addendum to the Nativity story that Matthew included after seeing the 66BC apparition of Comet Halley. Similarly, a lecture at the University of Castilla la Mancha in Spain led to an interesting post-lecture debate.


One thing that is evident to all who look into the matter of the Star of Bethlehem is just how confusing things are and how much is based on guesswork, sometimes educated, sometimes less so. With so many guesses involved it is not surprising that the subject of the Star has taxed philosophers, historians, theologians and astronomers for nigh on 2000 years. However, the guesses involved and the answers that one believes in case of conflict between different sources have a profound impact on theories.


The following is anything but complete, but comments on some of the most evident and problematic questions.


The date question: the Gospels


There is profound disagreement on the dating of the Gospels. This has a significant impact on some theories and a profound impact on one recent one.


Some sources date the writing of the Gospels as early as 50-60AD. This has the advantage of allowing them to be eyewitness accounts of the works of Jesus and written comparatively soon after his death.


When writing my book “The Star of Bethlehem – An astronomer’s view” (Princeton University Press, 1999) I initially used the chronology given in my Spanish translation of the Bible (Editorial Herder, Barcelona, 1976) and outlined by Friar Seraphim de Ausejo in his notes and introduction to the Gospel. This suggested that Matthew was written between 60 and 70AD, with a probable date between about 68 and 70AD (peer review suggested that this dating was unrealistic and a much later date was used in the published manuscript).


The evidence for early dating is that Matthew does not speak of the fall of Jerusalem in 70AD, thus it is suggested that the Gospel must date from a date slightly prior to the fall of the city to the Romans.


However, other sources are what we might call “late daters”. They suggest that the Gospels, with the exception of Mark, were written much later and that they cannot possibly be eyewitness accounts because they date from 50-60 years after the Crucifixion.


The advisors used by Princeton University Press suggest, as do many academics (here, as I am not an expert on Biblical chronology I have to trust what genuine experts think), this much later date for Matthew’s Gospel between 85 and 95AD and probably about 90AD.


The reasons for this are subtle; what we could call contextual clues. Here we will see one of the first of the profound disagreements where, starting from the same information, there are two totally opposite interpretations. The late-daters suggest that Matthew does seem to know in his Gospel of the fall of Jerusalem and of the destruction of the Temple. They also point to stylistic clues in the Gospel that suggest a later date of writing, within a more organised church. Luke goes as far as to open his Gospel with a highly revealing comment he has written his story “after investigating everything carefully from the very first” and noting that the accounts that “many have undertaken… were handed on to us by those who… were eyewitnesses”. In other words, Luke is stating explicitly that he was not a witness of the life of Jesus and seems to suggest that the other Gospels were similarly not eyewitness accounts.


The consequences


The fact that different biblical experts reading the same text of Matthew can conclude both that it assumes the fall of Jerusalem and that the author had no knowledge of that fall should give an idea of the sort of problems that we face when a large part of our interpretation of the Star of Bethlehem is based on Matthew’s Gospel.


The date question is not particularly critical to most Star of Bethlehem theories, however, there is a logical suggestion that events that are described a full century after they occurred will be less accurately related than those that are written maybe less than 60 years after the event. In other words, if Matthew and Luke wrote around 90AD and 85AD respectively they were writing some 90-95 years after the Nativity and thus errors and omissions are more understandable than if the Gospels were written little more than two generations after the Nativity. This has strong implications for second date question and the contradictions between Luke and Matthew.


There is though one highly date-critical theory of the Star of Bethlehem. A recent theory published in the Journal of the British Astronomical Association in December 2004 (Jenkins, R.M.: 2004, J.Br.Astron.Assoc., 114, 336-342). This suggests that Matthew included his account of the Star having seen the 66AD apparition of Halley’s Comet and the procession of Magi in Rome to pay tribute to the emperor Nero that occurred close to that time. As it had been in 12BC, this was a moderate apparition of the comet with it visible for 74 days after perihelion and reaching a theoretical magnitude of +0.9. The apparition though has entered history for the famous observation of the comet above Jerusalem shortly before its fall that many people interpreted as being foretold by the comet’s appearance.


If Matthew was written around 70AD the Halley’s Comet theory has a strong basis. Matthew was based in Rome and the combination of seeing the procession of Magi and observing Halley’s Comet, followed by news of the fall of Rome would have left a strong impression on him and would have been an obvious source of the mystical first few verses that he writes in his story of the Nativity. If, in contrast, Matthew was written some 20-25 years later, the case for this theory becomes so much weaker with the increasing distance from the events that are ascribed as his inspiration for the Star.



The date question: Luke v Matthew


Around Christmas many proud parents attend Nativity plays in which their children participate. Few though seem to notice that the traditional Nativity play is a mishmash of Matthew and Luke’s versions of the Nativity with almost nothing in common. Both Matthew and Luke give very clear and strong indications of the date of the Nativity. Unfortunately though, the two dates are in disagreement by at least ten years.


The elements in Matthew’s version of the Nativity are: King Herod, the Magi, and the Star.


In contrast, Luke mentions Caesar Augustus, Quirinius the Governor of Syria, the global census, the journey to Bethlehem, the inn being full, the child lying in a manger (Matthew, in contrast, states that the Magi found the child with his mother in a house) and the annunciation to the shepherds.


Here we have a clear contradiction. If the census and the journey to Bethlehem were critical in the Nativity, why does Matthew not mention them? If the Star and the Magi were critical, why does Luke not mention them? One answer that is offered is that Luke and Matthew were interested in different aspects of the Nativity with Matthew highlighting the more mystical aspects and Luke the historical details. This ties in with Luke being remembered as a doctor and amateur historian, while Matthew was an evangelist.


However, we cannot get around the date question. Just about the only aspect of the Nativity on which there is unanimous or near-unanimous agreement is the fact that Herod died in 4BC, a fact dated by the March 13th 4BC lunar eclipse that preceded his death. We know that on his death Judea was divided between his sons, with each ruling part of the kingdom (in at least one case, with disastrous results). This places the Nativity before 4BC, possibly in 5 or 6BC, although some experts push it back as far as 7BC. However, we know that Quirinius was Governor of Syria in 6-7AD. In other words, Luke’s Gospel states very clearly that the census was made in 6 or 7AD and thus that the nativity occurred then. This places Luke’s date for the Nativity at least 10 years after Matthew’s and possibly as much as 13 years later.


This is a massive and highly controversial discrepancy. All manner of solutions have been suggested. However, it is generally pointed out that Luke was a historian, if an amateur one and very careful with his details; the strong implication is that Matthew was a sloppy researcher who, if he could be so wrong with such important details, could not be relied upon to recount the story of the Star correctly.


Certainly the “Quirinius Problem” is intractable. Although all manner of alternatives to Luke’s chronology have been suggested that allow Quirinius to be in Syria in 8-6BC, none get over the basic problem that the words that the census “was taken when Quirinius was Governor of Syria”. Some desperate attempts have even been made to have Herod the Great live until Quirinius’s governorship, something that is even less plausible. The only suggestion that does make sense is the one that Luke made a mistake, or that there has been a mistranslation. It is an oft-quoted remark that reading a translation is like looking at the reverse side of a tapestry. Think then of the problems in dealing with an English (or Spanish) translation of a Greek text that was in turn produced from an Aramaic original (as may have happened).


Luke’s chronology does raise some interesting problems as the date of the crucifixion is suggested by many authors to have been in 33AD (although my Herder Bible suggests 30 or 33BC), with Luke stating that Jesus started his ministry at the age of “about 30”. Had Jesus been born in 7AD he would have been at most 26 when he died, clearly incompatible with Luke’s statement that he was 30 on starting his ministry; an earlier date for the crucifixion just make this incompatibility worse.


An interesting sidebar on this question is one that most authors have discounted, probably unfairly and possibly even unjustifiably: this is the chronology of Dionysius. Dionysius Exiguous was the Scythian monk who, in the 6th Century AD, fixed the modern Christian calendar. Much is made of the fact that Dionysius committed two “errors” when fixing the date of the Nativity by counting back the dates of the reigns of Roman emperors. In fact, only one of the two was actually an error. Dionysius was hamstrung by the fact that Roman numerals did not use the number 0; in fact, there was no Roman use of zero, largely because with X=10, C=100, M=1000, etc. there was no need for a “0”, which was only introduced when Arabic numbers entered common usage. Thus Dionysius’ calendar jumps straight from 1BC to 1AC without the year 0. More serious and definitely culpable was his failure to recall that Augustus Caesar has reigned for four years under his given name of Octavian. With this 5-year error Dionysius’ date for the Nativity is pushed back to 5BC, one year before the death of Herod the Great.


This 5-year error is used to justify throwing away completely the Dionysian chronology on the grounds that we do not know if he committed more errors. This seems unfair and unjust as nobody has ever presented any evidence for what these further errors might be. The fact that Matthew and Dionysius give compatible chronologies for the Nativity is at least worth noting and seems to be generally ignored in the fuss over the Matthew-Luke incompatibility.


Although Luke does not mention Herod in his Nativity story in Luke 2, it is a misconception that Luke does not mention Herod. Luke 3 speaks of the time when “Herod was ruler of Galilee”, this though was Herod Agrippa, descendent of Herod the Great. Herod the Great appears though in Luke 1. In this chapter it is stated that in the days of Herod the Great Elizabeth was visited by an angel and became pregnant, although barren. Luke goes on to state in Luke 1:26-31 that in the sixth month of Elizabeth’s pregnancy the angel Gabriel visited Mary and announced that she was to bear a child. This seems to place the immaculate conception before 4BC rather than around 6AD. The possible confusion in Luke 1 between Herod the Great and his son, Herod Antipas seems to be eliminated because Luke calls Herod “King Herod of Judea” whereas Herod Antipas was only tetrarch of Galilee and Perea, not the united kingdom of Judea,


We thus have three lines of evidence that suggest that the Nativity was around 5BC rather than around 6AD. There is though a further clue in the New Revised Standard Version of the Bible as to whether it is Luke or Matthew whose chronology can be trusted.


The consequences


The date question is fundamental as many of the most plausible theories of the Star of Bethlehem (as well as some of the less plausible ones) are strongly date dependent. A not necessarily exhaustive list is:



Our report card for the four most plausible and widely accepted theories is thus:



Nativity date




Triple conjunction

Strongly favoured

Ruled out


Ruled out

Strongly favoured



Ruled out

Ruled out

Strongly favoured


Ruled out

Ruled out

Ruled out


Among the less-plausible theories we have



The census question: which census?


The new translation of the New Revised Standard Version states that Augustus decreed that “all the world should be registered”. It then continues “This was the first registration and was taken while Quirinius was governor of Syria”. This is a telling comment because we know when Caesar Augustus ordered censuses: it was in 28BC, 8BC and 14AD. Here we have a clear discrepancy in Luke. If we are talking of global censuses of the Roman empire the first was in 28BC, far before any date of conceivable interest to the Nativity. Thus, when Luke states that it was the first registration, he is clearly in error or not talking of an empire-wide census, despite the description of it as a decree “that all the world should be registered”.


It is generally assumed that Luke is referring to the 8BC census declaration. This though supposes a massive problem. The following inscription is the order to Publius Sulpicius Quirinius (born about 45BC) to hold a census (“Quirini Censum”), where Quirinius is described as “legato caesaris Syriae” (Caesar’s legate in Syria)



This is in disagreement with Luke’s statement that Quirinius was governor of Syria when the census was taken. None of the three known censuses coincided with Quirinius’ governorship in 6-7AD. Multiple solutions have been suggested. The most popular revolve around two possibilities: that Quirinius held a high office other than the governorship in Syria around 8-6BC; or that Luke is mistranslated and that the Greek word used means “prior to” Quirinius’ governorship, such that Luke would actually be stating that this was the last census before Quirinius became governor.


So, once again, we have a strong indication that there is a problem with Luke’s chronology of the Nativity, as commonly accepted, giving a 6-7AD Nativity. And, once again, if the 8BC census is the one being referred to, we have a confirmation that Matthew’s chronology is essentially correct, with the Nativity in the 7-5BC range, allowing time for the census to be promulgated and implemented efficiently.


A second and not inconsiderable problem is the relevance of the census. Augustus ordered censuses in part for tax-gathering purposes, but his largest motive was to have accurate population statistics and to know if the population of the empire was growing under his rule. Here though the word “empire” is relevant: Joseph was a citizen of Judea, a Roman protectorate, not part of the empire (hence Quirinius was governor of Syria, not Judea). Until the Romans finally conquered Judea in 70AD the citizens of Judea paid their tribute to the king, although the Romans maintained a military presence in the region (most famously personified in the form of Pontius Pilate) and Judea used Roman coinage (“render unto Caesar what is Caesar’s”). Joseph would not have been required to register in a census of Roman citizens.


However, there are other possible options. Caesar Augustus was an efficient and organised ruler. A protectorate like Judea might have been requested to hold a register of able-bodied males for military service, or for an oath of loyalty to the emperor. Such options make more sense. The Roman Empire conferred increasing privileges on regions that showed the strongest loyalty and integration, thus giving strong incentives to peaceful rule and co-existence. People respond that the decree was directed at “all the world”, in other words, a global registration of the entire Roman world, but we encounter the same problem… why should Herod’s citizens respond to a decree from Rome? As a strong, autocratic and occasionally brutal ruler, especially towards the end of his reign, Herod the Great would have had strong views on Roman interference in Judea that would have reduced his authority amongst a notoriously rebellious population. One can only suspect that hyperbole was as common in Roman times as it is today and that “all the world” is akin to an American President’s typical comment in a speech that “today, the whole world rejoices…”


The consequences


Really, the census gives the impression of being a red herring. It is not fundamental in any way except for dating. Provided that we can discount the comment that the census occurred during Quirinius’s governorship (in other words, 6-7AD) there is no really clear implication for any theory. The only significant impact is if the census is that of 8BC and if applicable to Judea (which we have seen is highly doubtful), it would support an earlier rather than a later date for the Nativity, which, as shown in our report card, has important implications for some of the most popular theories. A 7BC Nativity rules out strongly three of the four most popular theories, as well as demonstrating that the Dionysian calendar had additional errors to those that are known.


The Star’s behaviour: how did it move?


This is perhaps the most curious controversy and seems to be most prevalent in people who have repeated the comments of others rather than reading Matthew for themselves. The argument is that the Star moved erratically in the sky, first being in the east, then in the south, moving before the Magi and stopping, while appearing and disappearing at will. If the Star did behave as is commonly supposed, moving erratically in the sky, as has often been commented, there is no astronomical explanation. In fact, it is this combination of unnatural movement and the appearances of angels that seem to be the reason why some people even regard the Star as a flying saucer sighting.


What does Matthew actually say?


We have observed his star at its rising


This is uncontroversial. Stars, planets, even comets rise in the east. Matthew is saying unambiguously that the Star was in the east when first observed.


Herod… learned from them the exact time when the star had appeared


Again, there is no significant ambiguity. Some time had passed between the appearance of the Star and the arrival of the Magi at Herod’s court. If the Magi had come from a distant country this is no great surprise. Only if the Magi had come from a nearby region such as Arabia with the rapid transit time to Jerusalem by boat around the coast and then up the King’s Highway from the top of the Red Sea, would there be a possible timing problem. Magi arriving from Babylon would though have posed an interesting difficulty. It is generally supposed that they would have taken the straight-line route across the desert, some 800km to Jerusalem, with its likely journey time of several weeks however, a possibly more logical route (certainly a quicker and more comfortable one) would have been by boat down the river Tigris or Euphrates to the Arabian Gulf and then by coastal vessel to the Red Sea. However, the increasingly popular idea that the Magi were Persian priests implies a long journey time and long visibility for the Star – there would be no reasonable alternative to the long land route as the Arabian Gulf was almost as far away as Jerusalem itself.


He [Herod] sent them to Bethlehem… and there, ahead of them, went the star that they had seen at its rising, until it stopped at the place where the child was.


Bethlehem is about 10km due south of Jerusalem. This passage simply states that the Star was in the south as they travelled to Bethlehem from Herod’s court.


The fact that the Star moved from the east to the south has been given as a strong justification for it being (a) a comet, (b) the triple conjunction, and (c) the planet Jupiter (before the 6BC occultation). The reasoning is that planets move backwards and forwards at different moments, with the retrograde loop (i.e. the planet apparently moving backwards) happening as the Earth passes a planet in its orbit. In the 7BC triple conjunction, Jupiter and Saturn made non-concentric retrograde loops, allowing the three close approaches over 5 months. The stationary points as the planets reached the extreme of a loop are used to explain how the Star could “stand over” Bethlehem. That the planets reverse direction in the sky explains how the Star “went before” the Magi. Similarly, a comet may cross the entire sky, particularly if it passes inside the Earth’s orbit and allows many possible variants on its movement.


The explanations of the Star’s apparent movement are ingenious and often compelling.


They are also completely unnecessary.


All stars rise in the east and set in the west. All stars with a declination south of the observer’s latitude pass through the south. The perspective of the Earth’s movement in its orbit also causes stars to move progressively through the year, with a star that first appears low in the dawn sky moving round to the south at dawn approximately three months later.


In other words, Matthew describes the movement of a totally normal star. They first saw it in the east at dawn. Some weeks or months later it was in the south when the Magi left Herod’s court (presumably before dawn) to travel to Bethlehem. There is no mystery in this whatsoever. The Star was in the south. The Magi were travelling south, so the Star went before them.


The only possible difficulties in Matthew’s comments are the possibility that the Star had disappeared and later reappeared and the matter of the Star stopping “over the place where the child was”. On the former, Matthew is slightly ambiguous (and in this field any slight ambiguity has provided a feast for the theorists). He talks of “the Star that they had seen at its rising” (my italics). Does this suggest that the Star had vanished for a time and then reappeared? Certainly, if it does it is not as clear as the comments that the Star had appeared in the east and was later seen in the south. Even so, there is no need at all to imply unusual behaviour on the part of the Star. Once a month there is a full moon; at full moon its brilliance hides all but the brightest stars and even these are hidden if the Moon passes nearby. Combine the full moon with a few cloudy nights and it is easy to see how the Star could have passed unobserved for a few days or even a week or so, particularly if not exceptionally bright at the time.


How about stopping “over the place where the child was”? Stars do not “stop”. Here is what is apparently the strongest argument in favour of a planet or a comet. A planet’s stationary point would cause it to stop among the stars. However, once again, we are overcomplicating and over-interpreting matters. The Star went before the Magi and stopped on a 10km journey; even making generous allowance for lack of hurry we are talking of the Magi being on the road 2-3 hours at most. Planetary movements and stationary points, on the other hand, are detectable over days and, more normally, weeks and are of no conceivable relevance here. Similarly, a comet can be seen to move from night to night but over a few hours its movement is negligible.


It is far easier to suppose a perfectly innocent explanation with which almost everyone, knowingly or not, is familiar. When one is out driving at night in the countryside you will sometimes have noticed that if the moon, or a bright planet such as Venus is low in the sky to one side of the car it seems to be following you. This is a well known illusion caused by the movement of foreground objects relative to the object in the sky and has probably been the cause of some “close encounter” UFO sightings. Similarly, when you have an object more or less in front of you it seems to move before you, tracking your own movements and always staying tantalisingly out of reach in front. Only when a building rises in front of you does the object seem to stop as the perspective changes.


The consequences


Several theories, particularly the triple conjunction and the occultation, are strongly dependent on the Star appearing and disappearing and its apparent movement in the sky to be plausible. Make the Star’s movement completely natural, like any other star in the sky and these theories are greatly weakened, although not necessarily fatally wounded. Of course, the converse is also true: if the Star’s movement was not the normal diurnal displacement that all stars show, theories that require the Star to be a normal star are fatally wounded (he who liveth by the sword dieth by the sword).


However, the simplest interpretation of Matthew and taking what he says at face value with no complicated linguistic or logical gymnastics is that Matthew is describing the normal day-to-day movements of a completely normal and stationary star. There is no need at all to over-complicate things and make the Star do anything other than follow its normal course in the sky.


One specific question: which Chinese star?


This is only relevant to one group of theories – the ones that suppose that the Star of Bethlehem was the object, or objects, seen by Chinese and Korean astronomers in 5 and/or 4BC. Here, some puzzling mythology has evolved suggesting that we must select the evidence carefully and assume that there are convenient errors where facts are inconvenient. The implication is clear: the oriental reports are too unreliable to be any guide. Such criticisms though are themselves based on a careful selection of the evidence.


Only two events are found in oriental chronicles that are dated around the time of the Nativity. Few indeed are the objects recorded within the 10 years before and after 1AD. The two events that are recorded around 5BC are though very interesting indeed, even if they have caused no end of controversy.


In the book called the “Ch'ien-han-shu”, we find the following reference:


“In the second year of the period of Ch'ien-p'ing, second month, a hui-hsing appeared in Ch’ien-niu for more than 70 days”


The second year of the reign of Ch'ien-p'ing meant the year 5 BC and the second month, in the Chinese calendar, implied the month that ran from March 10th to April 7th. A hui-hsing is a broom star and Ch'ien-niu is the Chinese constellation that included Alpha and Beta Capricornii. Thus the complete translation should read:


“During the interval between March 10th and April 7th of 5 BC, a comet appeared close Alpha and Beta Capricornii and was visible for more than 70 days”


Curiously, the chronicle appears to state that the object remained fixed in the same place in the sky for more than two months, which is rather unexpected if it were a comet. Chinese chronicles were generally meticulous in recording the tracks of comets and often gave details of tail length and even colour. If this was indeed a comet, only an extremely slow moving (and thus distant) object would have not moved enough in ten weeks to merit mention of its track


In the Korean chronicles, a second record is found from about this date in the “History of Three Kingdoms- the Chronicle of Silla (Samguk Sagi)”


“Year 54 of Hyokkose Wang, second month,  (day) Chi-yu, a po-hsing appeared in Ho-Ku”


“Ho-Ku” is the Chinese constellation, or asterism, which includes Altair and various stars of the south of Aquila (the Eagle). A po-hsing is a bushy star: an extremely bright star with rays, or a tail-less comet. The problem here is the date that is given; the day Chi-yu did not exist in the second month of the year. It is almost as if the chronicler had written that the star had appeared on February 30th.


One way of resolving the problem is to suppose that “Chi-yu” really should be “I-yu”, a character written in an almost identical fashion in Chinese and easily confused with it. If so, the chronicle really states:


“Year 54 of Hyokkose Wang, second month,  (day) I-yu, a po-hsing appeared in Ho-Ku”


Day “I-yu” of the second month of year 54 of Hyokkose Wang corresponds to March 31st, 4 BC. Thus the translation would be:


“On March 31st of 4 BC a bushy star appeared close to Altair”


Thus, apparently, two objects were seen, one in China in 5BC, the other in Korea in 4BC. This is, in itself suspicious. Chinese astronomers were meticulous and assiduous – if the far less advanced and thorough Koreans saw the object in 4BC, how did they not see it? Similarly, one can ask how, if they could see an object that the Chinese could not see in 4BC, why did the Koreans not observe the 5BC Chinese star?


In 1977 a group of British researchers (Clark, Parkinson and Stephenson, 1977: QJRAS, 18, 443) pointed out that this curious discrepancy in the date, due to the confusion between “Chi-yu” and “I-yu”, leads to a strange series of coincidences:


1.    ) Apart from the difference of one year, the date of appearance (March) is the same for both objects.


2.    ) Both objects appeared in the same region of the sky; the asterisms of Ho-Ku and Ch'ien-niu are close to each other, with Altair being located in the sky just a few degrees north of Alpha and Beta Capricornii.


3.    ) The objects are both described as comet-like (“hui-hsing” and “po-hsing” respectively) but there is no indication that either of them moved across the sky in cometary fashion.


This led them to the conclusion that there were only two possible explanations for the two records:


·      That the two objects were really the same one, with the year also in error in the Korean chronicle. In this case the object must have appeared close to the border between the two Chinese asterisms, hence it was located between Altair in the north and Alpha and Beta Capricornii in the south. The star would thus have been positioned, they concluded, quite close to the 3rd magnitude star Theta Aquilae.


·      That a comet and a nova, or two bright novae appeared in the same region of the sky, around the same date, in consecutive years.


Of the two explanations, the first is much more plausible than the second, especially considering that the records which are being translated are transcriptions and re-transcriptions of the originals, which were made several centuries later. The idea that two bright comets or novae could appear in the same part of the sky, on the same date, in two consecutive years, seems incredibly implausible. It also seems unlikely, given the known record of the Chinese as observers, that the Koreans would record the 4 BC object, but the Chinese not, particularly as this was an early era for Korean observations.


This has led to the suggestion that we can only reconcile the Chinese and Korean observations by assuming convenient errors in both chronicles and electing the parts of each that we wish to believe. This is most evidently not true. No evidence has ever been presented that the Chinese chronicle is in error apart from the suggestion that the term “hui-hsing” was incorrectly used (and even then this criticism is only relevant if we assume that the Star was a nova). This though highlights a frequent ambiguity in terminology. Although the Chinese used “ko-hsing” (guest star) for novae and supernovae, its usage was inconsistent. Tycho’s Star – the supernova of 1572 – was described by the Chinese, not as a ko-hsing, but as a hui-hsing. Tycho himself commented on observing the supernova for the first time “I am certain that the comet had not been present the previous night”. In their book, “The Historical Supernovae”, Clark and Stephenson encounter numerous cases of objects that are described in Chinese chronicles as hui-hsing or po-hsing, but which appear to be novae (or, potentially, supernovae); bright objects were often described as comets both by oriental and by European astronomers, a fact conveniently overlooked by the critics.


Another point made by the critics of the identity of the Chinese and Korean observations is to say that the named constellations – Ch’ien-niu and Ho-Ku – are not near neighbours, but actually widely spaced in the sky, so the discrepancy between the positions of the two objects precludes them being identical. Here we are in the terrain of matters of opinion.


The star Altair that is, according to Hoffleit, the centre of the constellation of Ho-Ku (the position given by the Koreans) and the star Beta Capricornii (the centre of Ch’ien-niu, the position given by the Chinese) are separated by almost exactly 20 degrees in the sky, a significant, although not huge difference. The two constellations are separated by Thien-Fu, a small asterism formed by Theta and Eta Aquilae (the former magnitude 3.3 and the latter, a variable with an average magnitude below 4 – of these three Chinese constellations, Thien-Fu is the smallest and faintest). Clark et al. get over this difficulty by assuming that the object appeared in the south of Aquila, in Thien-Fu or in the rather barren area between Ch’ien-Niu and Thien-Fu – itself an invitation to an ambiguity in the reported position –, probably somewhere in a circle of around 5 degrees around Theta Aquilae.


It is though, not inconceivable, in fact it is even probable that the careful Chinese reported a more or less accurate position, whereas the Koreans simply selected the nearest bright star and gave that as the position, hence the discrepancy between the two sources.


The consequences


The consequences for the theory that the 5BC Chinese nova was the Star of Bethlehem depend entirely on the level of proof (or, degree of tolerance) that one wishes to apply. Details that appear insignificant to one person may seem grave to another.


For many people the discrepancy between the Korean and Chinese records is a matter of a comparing the impressions of accurate, reliable and careful observers that had a long astronomical tradition with those of a group that had little tradition at the time and was notoriously less accurate – in case of discrepancy, believe the Chinese; however, others find the differences between the Korean and the Chinese chronicle alarming and suspicious and ask if, given so many errors and discrepancies between them whether or not either chronicle has any credibility at all.


Similarly, the fact that the Chinese do not use “ko-hsing” to describe the object is often regarded as a serious difficulty, despite the fact that the Chinese describe a stationary position over 10 weeks in an area of the sky at low galactic latitude (i.e. where novae are expected to appear in the sky). If it walks like a duck and quacks like a duck is it a cow just because someone tells you that it is?