Jyotish. Andrew Mason

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      Solstices and equinox ad 522: Revati Yogatârâ 359° 50′ (ζ Piscium), datum point for Revatipakṣa Ayanāṃśa. GC = galactic centre.

The three Yogatârâ of greatest concern to this narrative are Ashwini, Chitrā and Revati,11 sequentially representing the first, middle and last of the Nakshatras and, latterly, the start, middle and end of the solar zodiac. Ashwini and Revati we’ll consider briefly here; the importance of Chitrā will be outlined in Section 1.6.

The close of Revati12 Nakshatra is marked by a Yogatârâ (of the same name), close to the ecliptic in the constellation of Pisces. Today this star is most commonly identified as ζ Piscium. Due to its 5.2 magnitude it is easily lost to the naked eye, making its choice questionable for such a significant Yogatârâ, that is, that which marks the commencement of the sidereal sphere – 0° Ashwini and subsequently 0° Aries.13

The importance attached to this part of the sky has led some researchers14 to conclude that another star close to ζ Piscium may once have been preferred, but has subsequently been lost to us. Others have considered the possibility that ζ Piscium’s radiance has diminished over the ensuing millennia. Needless to say, there is much conjecture over missing, muted and/or surrogate star theories.

From an astronomical point of view ζ Piscium is not a singular star but in fact a trinary, meaning what is apparently singular (to the naked eye) is in actuality three stars separated by great distance, these being: ζ A15 (+5 magnitude), ζ B16 (+6 magnitude) and ζ C17 (a white dwarf companion to ζ B). White dwarfs are often interpreted as stars of failing longevity so there is a possibility that a more active ζ C had at some point in the past been more radiant.18 Additionally, many stars exhibit degrees of variability19 over time, their incandescence shifting substantially or subtly. During such periods, luminance may range from thousandths to several increments of difference in magnitude.20

      According to recent findings; our own pole star α Ursae Minoris is currently 2.5 times brighter than it appeared in the first century AD to notable astrologer/astronomer Claudius Ptolemy. There is also the enigma of irregularly variable stars, such as η Carinae, surrounded by the Homunculus Nebula. Between the 1830s and 1850s η Carinae was gauged to be the second brightest star in the southern hemisphere.

      Could ζ Piscium (trinary) have displayed similar irregularities over the millennia?

With something like five thousand stars visible to an unaided eye, making sense of the stellar clutter is a challenge to any observer. Admittedly, over time and with familiarisation, patterns slowly come into focus, but generally any foray out on a clear night requires good orientation skills and visual acuity. It soon becomes apparent that an equidistant distribution of stars along the ecliptic or lunar orbit is non-existent and that that all divisions are idealised. Astrology therefore seeks to impose order upon apparent chaos. As zodiacal constellations remain greatly unequal in proportion, their man-made borders (according to various sources) divide the heavens into lots of 30°, 13° 20′ and 3° 20′,21 and so on. The ancients called the zodiac ‘Manomaya Chakra’ or ‘mind-wheel’, reminding us that any segregation of the heavens ultimately resides within the minds-eye of the beholder.

1.4 THE PHENOMENON OF PRECESSION

      Ecliptic and equatorial plane key:  = 0° Aries (spring equinox),  = 0° Cancer (summer solstice),  = 0° Capricorn (winter solstice), GNP = Geographic North Pole, GSP = Geographic South Pole, ZNP = Zodiacal North Pole, ZSP = Zodiacal South Pole.

Inclined to the Earth’s equatorial plane at an angle of about 23.5°, the ecliptic was and is a very convenient reference point with which to measure the relative distances between various astronomical bodies. Following their varied orbits, the planets in our solar system appear to stray no more than 9°+/–22 above or below this convenient reference plane.

      Due to a phenomenon known as equinoctial precession, the point at which the ecliptic and equatorial plane meet, that is, the equinoxes, does not remain fixed. Instead these points slowly retrograde over time. Currently the spring equinox frames our Sun against the constellation of Pisces, but this was not always so. Fifteen hundred years ago it was the constellation of Aries that hosted the spring equinox. The rate of precession at this time is in the order of 1° every 72 years. This imperceptibly shifts our Sun backward through each zodiacal sign in a period of 2160 years. The Sun then circumnavigates the entirety of the zodiac every 25,920 years.

      Note: When considering precession it should be kept in mind that this is a direct consequence of Earth’s own orbital instabilities and has nothing to do with the position of the Sun, which remains at the centre of the solar system.

      Equinox and solstices: 1 = spring equinox (days of equal length), 2 = summer solstice (longest day), 3 = autumnal equinox (days again of equal length), 4 = winter solstice (shortest day). Key: GNP/GSP = Geographic North and South Poles, ZNP/ZSP = Zodiacal North and South Poles.

      Although the true mechanism behind precession is not understood (see Section 1.5) its measurement at the spring equinox allows its variable rate to be determined and averaged. Ayanāṃśa therefore is a corrective value applied to the Sun’s current position at this equinoctial juncture – effectively reasserting a point from a former epoch – previously agreed to represent 0°, that is, the initial point of the zodiac.

      Of course the exact date of this reasserted point is hotly debated, but for the sake of argument we’ll assume the last time it occurred was AD 522. Taking this date as coincident, there is currently some 20°+ difference between the Sun’s current position and its former position as of 1493 years ago.

Although the Sun’s location (at the spring equinox) has some tradition of being used to identify 0°, it is not known how long observers were aware of this position’s instability, due mostly to its imperceptible crawl. In truth, remote sky-watchers were probably more akin to seeing precession in terms of solstices23 rather than equinoxes – the latter marking an highly important yearly juncture in their calendar such as the Sun’s movement from south to north, that is, marking the longest and shortest day of the year. See the equinox and solstices diagram above.

      Ancient solstices (c. 1225 bc+/–) coincide with the middle of Aslesha Nakshatra (ε Hydrae) and the start of Dhanistha Nakshatra СКАЧАТЬ