PART IV
Comments on
"ECLIPSES AND THE PROMISED MESSIAH"
by Dr David L McNaughton
15th November 1995
("Eclipses and
the Promised Messiah", by Dr Muhammad Aslam Nasir, was placed on the
Internet under " Review of Religions" in March 1994.)
Dr D L McNaughton is a South African meteorologist and astronomer working
at Dubai Airport in the Meteorological Office. He is responsible for
answering all queries of an astronomical nature and is considered to be an
authority on this subject in the UAE. He is well known for his valuable
contributions of articles in this field to magazines and journals both
locally and internationally for the past several years.
In addition to the
following article, at our request, Dr David has examined the occurrenc
e of double-eclipse Ramadans and the statements made by
Mirza Ghulam Ahmad Qadiani. His paper will shortly appear in Hamdard
Islamicus and will be placed here as well, Insha Allah.
- The foundation-stone of Dr Muhammad Aslam Nasir's thesis is his very
drastic reinterpretation of the words of Imam Muhammed al Baqir ibn 'Ali ibn
Husain. That Imam's statement about a lunar eclipse on the first
night of Ramadan, is regarded by Dr Muhammad Aslam as
referring to the 13th of Ramadan - by arguing that the 13th
is the earliest Ramadan date when such an eclipse is possible. Similarly,
Imam Baqir's stipulation of a solar eclipse "in the middle of Rama
dan" has been reinterpreted by Dr Muhammad Aslam as one which would take
place on the 28th of Ramadan!
According to many accounts, when Imam Muhammed al Baqir made his prophecy,
one of his companions suggested that he might have inadvertently reversed the
order of the two eclipses. However, the Imam replied that he had not made a
mistake. If indeed ( as Dr Muhammad Aslam claims) this Imam had really meant
to specify the 13th and 28th of Ramadan, then surely he would have explained
that when questioned.
- The above "alteration" of those Ramadan dates is
compounded by additional uncertainty - because of flexibility in specifying
exactly where crescent sightings are made, when defining the start of that
lunar month.
Islamic countries occupy a wide range of longitudes between eastern Asia and
northwest Africa, so their calendars do not always follow the same Gregorian
dates. There is also a marked bias between the northern and southern
hemispheres: e.g. it is often easier to spot a new-born crescent from
southeast Africa than it is from a Levantine country on the same longitude
(or vice versa) - because of the different angles between the ecliptic and
the horizon at dusk.
Furthermore, there are other Islamic calendar systems in use which eliminate
any dependence on lunar observation: such a calendar (based on a 10631-day
cycle) has been adopted by the Bohra community, and (for certain months) by
the Saudi Arabian authorities. It often runs one or two days behind calendars
which conform strictly to crescent-sighting.
Thus, it is probably unproductive to attempt to examine whether or not
particular eclipses did in fact occur (or commence ) on the 13th of Ramadan,
or on the 14th, or whenever, because of the difficulty in deciding which
Islamic calendar should be utilised.
However, there is absolutely no doubt that there have
been many occasions when a lunar and a solar eclipse have both been witnessed
during Ramadan(McNaughton, 1995).
Dr Muhammad Aslam's article contains another time-misconception in his claim
that all eclipses are confined to one particular Islamic day. On the
contrary, it is by no means impossible for an already eclipsed moon to rise
as the sun sets, having been visible earlier on from countries further east.
Similarly, the sun may set while eclipsed - but continuing to remain eclipsed
and still above the horizon elsewhere. Alternatively, a solar eclipse
observed from west Africa or Europe will often begin before and e
nd after sunset in Pakistan, for example.
- Dr Muhammad Aslam's mention of errors in von Oppolzer's 1887 Canon of
Eclipses is misleading and inappropriate in view of the availability of more
accurate canons, such as those produced by Meeus and Mucke and by Bao-Lin Liu
and Fiala. (In fact, von Oppolzer's analyses were much better than Dr
Muhammad Aslam implies). Also, Dr Muhammad's excuse that past eclipses
cannot be checked properly because of fluctuations in Earth's rate of
rotation and in the moon's orbital motion - is yet another " red herrin
g".
If an eclipse-shadow is scheduled to brush the surface of the Earth, then it
will still do so even if our planet is suddenly forced to spin faster or
more slowly. Admittedly the eclipse timings will be affected (according to a
clock running on UTC) - but past records are almost always good enough to
confirm dates of occurrence - and indeed to enable scientists to deduce what
UTC time-correction is appropriate for each occasion. (The contribution made
to that discrepancy by variations in Earth's rotation-r
ate is known as the "Delta-T" value for the date concerned: these can be
estimated for the past much more reliably than for the future).
Despite what Dr Muhammad Aslam implies, year to year variations in the shape
of the moon's orbit can be modelled and calculated extremely well. Virtually
all astronomers agree that the Chapront ELP-2000/82 lunar theory is by far
the best one presently available. It is true that the moon's long-term
orbital deceleration is not known with 100 per cent. accuracy - but during
the last one or two centuries, eclipse times computed according to the
Chapront algorithm are nevertheless reliable to within a few secon
ds.
- Dr Muhammad Aslam's investigation of future eclipses up until AD 2100 is
unconvincing without a full exposition of criteria he adopted to decide on
the dates of 1st Ramadan. There is a wide "grey" area where crescent
sightability cannot be ascertained in advance because it depends very much on
the thickness of the low-level haze. This often raises doubt as to exactly
when Ramadan may commmence, and an error of a whole day is enough to destroy
Dr Muhammad Aslam's thesis.
A professional approach would also have stated what values were assumed for
the Delta-T correction, to allow for the slowing down of Earth's rotation; it
is just possible that other (equally plausible) values could alter at least
one of his dates.
REFERENCES AND BIBLIOGRAPHY
- Bao-Lin Liu and A.D Fiala, 1992: Canon of Lunar Eclipses, 1500
BC- AD 3000. Willmann-Bell Inc., Richmond, Virginia.
- M. Chapront-Touze and J. Chapront, 1983: The Lunar Ephemeris ELP
2000. ASTRONOMY AND ASTROPHYSICS 124, pp. 50-62. Improved expressions
are given in a later paper, 1988, in ASTRONOMY AND ASTROPHYSICS 190, p. 346.
Their book Lunar Tables and Programs from 4000 B.C. to A.D. 8000 is
published by Willmann-Bell Inc., Richmond, Virginia.
- DAR-E-QATNI 1, p. 188. This mentions the prophecy by Muhammed al Baqir
ibn 'Ali ibn Husain regarding eclipses preceding appearance of the Mahdi -
narrated by Amar bin Shamer, quoting Jaber.
- Explanatory Supplement to the Astronomical Almanac,
1992.University Science Books, Mill Valley, California. It contains a
chapter on "Calendars" and another on the "......Rotation of the Earth " as
well as discussions on Solar System dynamics.
- D.L. McNaughton, 1995: Eclipses during Ramadan. Accepted by
HAMDARD ISLAMICUS, Karachi. Winter 1995/96. Its Table 1 shows double-eclipse
Ramadans occurring every 22 or 23 Islamic years.
- J. Meeus, 1991: Astronomical Algorithms. Willmann-Bell Inc.,
Richmond, Virginia. Chapters 45,47, 48 and 49 discuss the moon's behaviour,
including variations in its distance from Earth. Chapter 52 is devoted to
eclipses and chapter 9 to fluctuations in Earth's spin-rate.
- J. Meeus and H. Mucke, 1983 : Canon of Lunar Eclipses, -2002 to
2526 (2nd edition). Astronomical Office, Vienna.
- H. Mucke and J. Meeus 1983: Canon of Solar Eclipses, -2003 to
+2526. Astronomical Office, Vienna.
- T. R. von Oppolzer, 1887: Canon der Finsternisse. Imperial
Academy of Science, Vienna. (1962 English edition published by Dover
Publications, New York).
- Also see Oppolzer's Great Canon of Eclipses by W.H.C. Carton in
SKY & TELESCOPE November 1989 , pp. 475-478.
SOFTWARE
EclipseMaster, SunTracker and MoonTracker are of high
quality (enabling eclipses to be examined on a personal computer). They are
available from Zephyr Services, Pittsburgh, Pennsylvania.
A companion diskette comes with Meeus's Astronomical
Algorithms.
You are welcome to write to David or drop me a note :
Dr David L. McNaughton
P. O. Box 1897
Dubai,
United Arab Emirates
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