[meteorite-list] OT - Happy Crab Nebula Day!

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Tue, 5 Jul 2011 01:49:03 -0500
Message-ID: <2404E68DE27F4466933EF73B2D40FF4A_at_ATARIENGINE2>

The Calendar-Go-Round!

    Simple answers first: if a source specifies "Julian calendar"
for the date of an event, it almost certainly means the event's date
in the Julian calendar system, proposed and enforced by Augustus,
Julius Caesar's adopted son and first Emperor of Rome.

    By the time Pope Gregory XIII decided the calendarical slide had
gone far enough, the Julian calendar of 1700 and the astronomical
calendar were 11 days apart, by the 1800's when Protestant Europe
adopted the "Gregorian" calendar, it was 12 days off. By 1917, when
revolutionary Russians changed their calendars, it was 13 days. The
Julian lags by one day every 143 years (since Year 1 AD).

    But it's messier than that. For example, when does a year begin?
Jan. 1? No, not for most of the past two millennia. Were calendars,
at a given time, the same in all countries? No.

    The Roman calendar began the year on 1 January, and this remained
the start of the year after the Julian reform. However, even after local
calendars were aligned to the Julian calendar, they started the new year
on different dates. The Alexandrian calendar in Egypt started on 29
August (30 August after an Alexandrian leap year). Several local
provincial calendars were aligned to start on the birthday of Augustus,
23 September.

    The indiction caused the Byzantine year, which used the Julian
calendar, to begin on 1 September; this date is still used in the
Eastern Orthodox Church for the beginning of the liturgical year.
When the Julian calendar was adopted in Russia in AD 988 by
Vladimir I of Kiev, the year was numbered Anno Mundi 6496,
beginning on 1 March, six months after the start of the Byzantine
Anno Mundi year with the same number. In 1492 (AM 7000),
Ivan III, according to church tradition, realigned the start of the
year to 1 September, so that AM 7000 only lasted for six months
in Russia, from 1 March to 31 August 1492.

    During the Middle Ages 1 January retained the name New Year's
Day (or an equivalent name) in all Western European countries
(affiliated with the Roman Catholic Church), since the medieval
calendar continued to display the months from January to December
(in twelve columns containing 28 to 31 days each), just as the
Romans had. However, most of those countries began their
numbered year on 25 December (the Nativity of Jesus), 25 March
(the Incarnation of Jesus), or even Easter, as in France.

    In England before 1752, 1 January was celebrated as the
New Year festival, but the "year starting 25th March was
called the Civil or Legal Year, although the phrase Old Style
was more commonly used." To reduce misunderstandings
on the date, it was not uncommon in parish registers for a
new year heading after 24 March for example 1661 had
another heading at the end of the following December
indicating "1661/62". This was to explain to the reader
that the year was 1661 Old Style and 1662 New Style.

    Most Western European countries shifted the first day of
their numbered year to 1 January while they were still using
the Julian calendar, before they adopted the Gregorian calendar,
many during the sixteenth century. The following table shows
the years in which various countries adopted 1 January as the
start of the year. Eastern European countries, with populations
showing allegiance to the Orthodox Church, began the year on
1 September from about 988.

    Note that as a consequence of change of New Year,
1 January 1751 to 24 March 1751 are non-existent dates
in England.

    The Julian calendar was in general use in Europe and Northern
Africa from the times of the Roman Empire until 1582, when
Pope Gregory XIII promulgated the Gregorian Calendar.
Reform was required because too many leap days are added
with respect to the astronomical seasons on the Julian scheme.
On average, the astronomical solstices and the equinoxes
advance by about 11 minutes per year against the Julian year.
As a result, the calculated date of Easter gradually moved out
of phase with the moon. While Hipparchus and presumably
Sosigenes were aware of the discrepancy, although not of its
correct value, it was evidently felt to be of little importance at
the time of the Julian reform. However, it accumulated significantly
over time: the Julian calendar gained a day about every 134 years.
By 1582, it was ten days out of alignment.

    The Gregorian Calendar was soon adopted by most Catholic
countries (e.g. Spain, Portugal, Poland, most of Italy). Protestant
countries followed later, and the countries of Eastern Europe
even later. In the British Empire (including the American colonies),
Wednesday 2 September 1752 was followed by Thursday
14 September 1752. For 12 years from 1700 Sweden used a
modified Julian Calendar, and adopted the Gregorian calendar
in 1753, but Russia remained on the Julian calendar until 1917,
after the Russian Revolution (which is thus called the 'October
Revolution' though it occurred in Gregorian November), while
Greece continued to use it until 1923. During this time the Julian
calendar continued to diverge from the Gregorian. In 1700 the
difference became 11 days; in 1800, 12; and in 1900, 13, where
it will stay till 2100.

    Although all Eastern Orthodox countries (most of them in Eastern
or Southeastern Europe) had adopted the Gregorian calendar by
1927, their national churches had not. A revised Julian calendar
was proposed during a synod in Constantinople in May 1923,
consisting of a solar part which was and will be identical to the
Gregorian calendar until the year 2800, and a lunar part which
calculated Easter astronomically at Jerusalem. All Orthodox
churches refused to accept the lunar part, so almost all Orthodox
churches continue to celebrate Easter according to the Julian
calendar (the Finnish Orthodox Church uses the Gregorian Easter).

    The solar part of the revised Julian calendar was accepted by
only some Orthodox churches. Those that did accept it, with
hope for improved dialogue and negotiations with the Western
denominations, were the Ecumenical Patriarchate of Constantinople,
the Patriarchates of Alexandria, Antioch, the Orthodox Churches
of Greece, Cyprus, Romania, Poland, Bulgaria (the last in 1963),
and the Orthodox Church in America (although some OCA parishes
are permitted to use the Julian calendar). Thus these churches
celebrate the Nativity on the same day that Western Christians do,
25 December Gregorian until 2800. The Orthodox Churches of
Jerusalem, Russia, Macedonia, Serbia, Georgia, Ukraine, and the
Greek Old Calendarists continue to use the Julian calendar for their
fixed dates, thus they celebrate the Nativity on 25 December Julian
(which is 7 January Gregorian until 2100).

    And... Here's a further deeper sample of calendrical complexity.

    Some examples: Should one use local solar time, local mean
solar time, or standard time? (Prior to the International Meridian
Conference in 1884, the records of that meeting indicate that only
four nations followed standard time systems: the UK, the USA
and Canada - but only just for those two, from the year before.
The Netherlands did not become part of the international standard
time system until 1954, for example.

    With the leap year scheme used in the Western calendar the
time of the vernal equinox ranges over 53 hours within 19-21 March,
producing a corresponding variation in the solar longitudes at which
January, or any other month, occurs.

    It has been assumed for a long time that the seasonal year follows
the spacing between the equinoxes and solstices, the *average* such
time being the familiar *tropical year* of 365.2422 days when again
averaged over some dozens of orbits. This assumption seems to be
wrong. The cycle time of the seasons over the past several centuries
(since temperature records began) is actually the anomalistic year,
the time between perihelion passages, which is near 365.2596 days
again when suitably averaged.

    Because perihelion passage shifts later by about one day every
58 years on the Western calendar, this would imply that not only
does 'January' oscillate by 53 hours in the leap year cycle, but also
the current January is shifted, seasonally-speaking, by more than
two days compared to 'January' back in 1867.

    Apart from anything else, if one kept a calendar held steady
against the perihelion position (and hence the seasonal cycle *at
present* - I would anticipate that this cyclicity is only temporary for
some centuries until perihelion moves far enough away from the
winter solstice to lose the resonance) then the 24-hour period
labelled 'January 31st (Eastern Standard Time)' would in the
past have been in February.

    This all comes back to the calendar one uses. I have employed the
term 'Western calendar', It is a fallacy that the calendar used as the
world-wide standard (with local or religious calendars also employed)
is the 'Gregorian calendar.' That is an ecclesiastical calendar adopted
by-and-large only in various Catholic states around 1582-1610,
persisting since in Italy and Spain. Elsewhere solar calendars have
been legally adopted (by other countries) in which the same
(inaccurate) leap year rule as the Gregorian happens to be used.
The Western calendar derives basically through the major powers:
Britain's calendar reform of 1751, which was inherited by the
American colonies and thence by the initial founding states of the
USA (note that the USA does not have any legal calendar code of its own,
the familiar system is just used by common assent there and hence
elsewhere). It is this which may be termed the 'Western calendar'.

    But that does not make the Western calendar the same as the
Gregorian.

    There are several very significant differences. The Gregorian is a
luni-solar calendar in that it provides for a lunar cycle as well as
a solar sycle. Everyone knows about the leap-year corrections (three
in 400 are dropped: 1700, 1800, 1900, 2100...) but few know also of
the lunar jumps: the lunar phase (the phase of the ecclesiastical moon,
not the real moon) is assumed to follow the Metonic cycle of 19 years
which is close to 235 lunations, except that over a period of 2500 years
there are eight single-day jumps interposed. This is done to
'regularize'
the date of Easter, the main aim of the Gregorian reform. The Gregorian
is a luni-solar religious calendar, whereas the Western is a solar civil
calendar. They are not the same thing.

    That is not to say that Lord Chesterfield's Act of 1751 did not
address
religious matters. It had to, because Great Britain (as it was then)
is a religion-based nation. The monarch is the 'Defender of the Faith.'
In this connection the Act contains several mistakes. For anti-Catholic
and anti-Semitic reasons the phraseology employed (oft-quoted by people
in
some form : "Easter is the first Sunday after the first full moon after
the
equinox") is nonsensical in itself, and does not lead to the Easter
dates
actually printed in the Book of Common Prayer, the tables there
following
the Catholic rules. The statement cited there would imply that Easter
cannot coincide with either an astronomical full moon or the Passover,
whereas such coincidences do occur. I might note that the first person
to have spelled out this nonsense, in about 1850, seems to have been
Augustus De Morgan, one-time Secretary of the Royal Astronomical
Society.

    On top of that - and this is significant - the Act mentions the
desire to
keep the solstices and equinox at the same seasonal dates. Leaving
aside
the recently-recognized fact that the seasons follow the anomalistic
year,
the implied necessary year-length for the calendar (the Western) as
defined
by that Act is the *tropical year* of 365.2422 days (on average, etc.).
The 'Explanatory Supplement to the Astronomical Almanac' (an official
publication of the US & UK governments) actually mis-defines the
tropical
year as the time between vernal equinoxes, and it is NOT. Because of
the
eccentricity of our orbit four different-length years result from the
times between vernal and autumnal equinoxes, and winter and summer
solstices. The Gregorian reform was based upon regularizing Easter and
thus keeping the date of the vernal equinox near-constant (which it
fails to
do; note the 53-hour range mentioned earlier), meaning that the year
counted between those equinoxes is what is needed. This is 365.2424
days
at present.

    This provides another reason why the Gregorian and Western calendars
are not the same thing: their target year lengths are different. That
difference in the fourth decimal place is significant. The mean
Gregorian year of 365.2425 days is much closer to the Vernal Equinox
year of 365.2424 days than the tropical year of 365.2422 days, as used
in the Western calendar. Arguments over whether we need a 'correction'
every 3200 or 4000 years, begun by astronomer John Herschel in 1828,
are thus specious (and apart from anything else, tidal drag is
lengthening the day as defined astronomically as opposed to
atomically).

    The Catholic Church in the later sixteenth century would
have produced a 'better' calendar if it had instead used a 33-year
cycle containing eight leap years, as does the Persian calendar. This
(i) Makes a year 365.242424... days long on average; (ii) Makes a cycle
short enough to keep the equinox within a 24-hour range; (iii) Leads to
a better solution of the lunar phase problem connected with Easter.

    There is more. The Eastern Orthodox Churches have suffered splits
since in 1923 it was suggested that they alter from the Julian calendar
to what has been called the 'Revised Julian'. This would have seven
leap year days dropped from nine centuries, such that the year would
average to 365.242222... days. This was to provide one-upmanship over
the Gregorian scheme, but it is based on the mistaken belief that the
*tropical year* rather than the *vernal equinox year* is the target.
There are still arguments within those Churches on this topic, mostly
based on a totally incorrect understanding of the astronomy.

    But this brings me full circle. So far as I am aware the only one
of
the Orthodox Churches to have adopted the Gregorian calendar is that of
Finland. Thus it is true that the Gregorian calendar is used in
Finland: within the Orthodox Church, and the Catholic Church. As for
the rest of the country, that is a different matter. One would need to
look at the Swedish legislation to see whether they adopted the
Gregorian calendar, in a legal act dated (I would imagine) 1752, the
year before the actual reform took place, although I am not sure
whether Sweden was using the March 25th New Year as was Britain until
31st December 1751. I would imagine that the Lutherans of Sweden, like
the Anglicans of Britain, would have written an Act which did not
mention the Catholic Church/Pope etc., but rather defined a parallel
solar calendar with some definition for when Easter is to be
celebrated. Perhaps they made the same silly (and
religiously-motivated) mistakes as did the British.

    It is very easy to make glib statements like "We use the Gregorian
calendar" without realizing what is actually involved. For example,
making January 1st the New Year's Day is often ascribed to the Gregorian
reform, but that is a false belief. It was already in use before that.
Off and on it has been used since at least 153 BC. Similarly we use
calendar months which have been unaltered since 45 BC, notwithstanding
claims that Augustus Caesar fiddled with them. Thus the months, as
such,
are not defined as part of the Gregorian calendar.

    Our year numbers are ordinals, not cardinals. Notwithstanding the
fact that we count a 'zeroth law of thermodynamics', and a 'zeroth'
Pharaonic dynasty in Egypt, it makes little sense to have a 'zeroth
year'. AD 1 is 'the first year of the Lord'. (1 BC is the 'first year
Before Christ', a seventeenth-century invention by an astronomer, by
the way.) One may wonder how AD 1 can be 'the first year of the Lord'
if he was born on December 25th (I am talking here about *traditional*
dates rather than historically-veracious dates). When Dionysius
Exiguus was setting up his framework for Easter dates in 525-253 (he
was not trying to define an era) he correctly recognized that a Jewish
boy's life is reckoned from his circumcision, not from birth.

   Thus Dionysius equated 1st January (in the year which two centuries
later became labelled AD 1) as the date of the circumcision, it being
the
start of the year. (Look into a Church Missal and you will find January
1st named as the Feast of the Circumcision, and our method of counting
years from that date is technically referred to as the *Stylo
Circumcisionis*.) Circumcision occurs on the eighth day counting
exclusively (see your Bible), putting the traditional Nativity on 25th
December 1 BC, which was the traditional (but not actual, even then)
date of the winter solstice festivities. (The early Church had actually
used January 6th, Epiphany, to avoid the pagan solstice celebrations.)
Dionysius then counted back the nine month gestation period to the
traditional (but not actual) vernal equinox of March 25th in 1 BC, and
he counted years from there as the *Anni ab Incarnatione*. This is the
year which astronomers call 0 (using cardinals) but is more generally
termed 1 BC (using ordinals). The fact that March 25th was the
Incarnation/Annunciation/Lady Day was what led to the British and
eventually American colonies using that date for New Year, although
counted FROM THE WRONG YEAR! (AD 1 instead of 1 BC).

    Although the USA now uses the Western calendar, and previous
to 1752 the Julian was used in the Atlantic colonies, do not imagine
that no use has ever been made of other systems. When the first
Catholic missionaries arrived, they imposed the Gregorian calendar.

   Thus when (say) Texas and California joined the USA, although
their dating systems may have been continuous they did move from the
Gregorian to the Western calendar. Those parts in the Louisiana
Purchase were on the Gregorian until they were administered for three
weeks under the French Revolutionary Calendar in late 1803, before
Napoleon sold the region to the USA. That's something to note next
time you eat Lobster Thermidor in New Orleans.

    Until Alaska was sold in 1868 to the USA it was part of the Russian
Empire, and thus on the Julian calendar. But it is more confusing than
that. The day of the week there was different to that throughout the
rest of North America. Although a change from Julian to Western (or
Gregorian) calendar did not involve a change in the day of week sequence
elsewhere, in Alaska it did because that region, in the absence of any
International Date Line, used both the date and the day of the week
appropriate for Moscow.

[Deep breath]

    But the date of the supernova is recorded in the Chinese calendar,
not the Western calendar, as "Zhihe era of the reign, first year, fifth
lunar month, ji-chou day," says the Wenxian Tongkao of 1280 CE
and the Xu Zizhi Tongjian Changbian of 1320 CE. But the Song
Huiyao, a Sung source, gives the date as "Zhihe era, first year, seventh
lunar month, 22nd day" when it was observed as a faint yellow
star that then brightened. The account contains considerable
observational detail: "...has been seen in daylight, like Venus.
It had rays stemming in all directions, and its colour was reddish
white. Altogether visible [in the day] for 23 days." This date would
shift the supernova date from the Fourth of July into September,
however.

    Japaenese sources (three) all agree with each other but put it
one linar month earlier than the Chinese account and are all
inconsitent with rising times.

    An Islamic oberservation was discovered in 1978 that places
the supernova in the year 446 of the Islamic calendar, which year
ran from 12th of April 1054 to the 1st of April 1055 (it's a lunar
calendar] at the summer low level of the Nile, which fits the July
date. Claims that certain vague European accounts are of the
Crab are rejected by most astronomers.

Interpretations of the dates are not straightforward. the 24th of
April and the 11th of May have also be argued for as the correct
date by various scholare. The July 4 date was calculated by
Jan Julius Lodewijk Duyvendak for Jan Oort in 1942.


Sterling K. Webb
-----------------------------------------------------------------------------------
----- Original Message -----
From: "MexicoDoug" <mexicodoug at aim.com>
To: <paw at wirelessbeehive.com>; <meteorite-list at meteoritecentral.com>
Sent: Monday, July 04, 2011 10:15 PM
Subject: Re: [meteorite-list] OT - Happy Crab Nebula Day!


>
> It ought to be Julian since that was in effect ... or else all the
> references would have to say something about the re-adjustment of the
> date, but that's just an opinion! In astronomy, generally the 1582
> conversion is respected by astronomers if I recall - I.e., before that
> time events are on the Julian Calendar, and afterwards Gregorian, even
> if they nation of the observation was still on the Julian date;
> usually that doesn't matter and by convention the expression I time I
> believe changes in 1582. Jean Meeus's incredibly useful books, if I
> had them would have an excellent discussion of the subject, but I
> don't have my references with me. Some other list member could look it
> up as Meeus'd be the expert.
>
> Best wishes
> Doug
>---------------------------------------------------------------------------
> -----Original Message-----
> From: Patrick Wiggins <paw at wirelessbeehive.com>
> To: MeteorList <meteorite-list at meteoritecentral.com>
> Sent: Mon, Jul 4, 2011 10:12 pm
> Subject: Re: [meteorite-list] OT - Happy Crab Nebula Day!
>
>
> I've often wondered and maybe someone here can answer.
>
> Since 1054 was long before the 1582 conversion from the Julian to
> Gregorian
> calendar, is the July 4 date that gets mentioned for the first
> sighting of
> supernova a Julian date or has it been converted to Gregorian?
>
> ???
>
> patrick
>
>
> On 04 Jul 2011, at 10:25, Gary Fujihara wrote:
>
>> Cosmic Fireworks: On July 4, 1054, Chinese astronomers observed a
> "guest star"
> in the constellation Taurus, the result of a star exploding or going
> Supernova.
> At mag -6, SN1054 (Supernova of 1054) became about 4 times brighter
> than Venus,
> was visible in daylight for 23 days, and lasted a period of two years.
> Today we
> can still see remnants of SN1054 as the Messier Object 1 (M1) Crab
> Nebula.
>>
>> http://bigkahuna-meteorites.com/_M1.jpg
>>
>> Oh, and for those terrestrially bound in the USA, Happy Fourth of
> July!
>>
>> Gary Fujihara
>> Big Kahuna Meteorites (IMCA#1693)
>> 105 Puhili Place, Hilo, Hawai'i 96720
>> http://bigkahuna-meteorites.com/
>> http://shop.ebay.com/fujmon/m.html
>> (808) 640-9161
Received on Tue 05 Jul 2011 02:49:03 AM PDT