Last Venus Transit of this century on 06-06-2012, Must watch for Everyone. ( Don’t forget to protect your Eyes)

1. Last Venus Transit of this century on 06-06-2012, Must watch for
Everyone. ( Don’t forget to protect your Eyes) :
Now a day’s evening star, I mean Venus planet is in its full glory. You can
observe it’s beauty after sunset till little late evening. It’s 12 to 15 times brighter
than Sirius, the brightest star of night. Now Venus is 20 to 25 degrees away from
Sun but it has already started approaching Sun and it will pass the Sun on 6th
June 1012, the event is called Venus transit.
The transit or passage of a planet across the face of the Sun is a relatively rare
occurrence. As seen from Earth, only transits of Mercury and Venus are possible.
On average, there are 13 transits of Mercury each century. In contrast, transits of
Venus occur in pairs with more than a century separating each pair. Transits of
Venus across the disk of the Sun are among the rarest of planetary alignments.
Till date only Seven such events have occurred since the invention of the
telescope (1631, 1639, 1761, 1769, 1874, 1882 and 08-06-2004). The next
transit of Venus will occur on 06 June 2012, this will be last Venus transit
observed by all of us in this century & our life also. Next will happen in 2117.
The 2004 transit has crossed the Sun's southern hemisphere while the 2012
event will cross the northern hemisphere. The apparent diameters of Venus and
the Sun are approximately 59 arc-seconds and 1890 arc-seconds respectively.
This 1:32 diameter ratio results in an effective 0.001 magnitude drop in the Sun's
integrated magnitude due to the transit.
Transits of Venus are only possible during early December and early June when
Venus's orbital nodes pass across the Sun. If Venus reaches inferior conjunction
at this time, a transit will occur. Transits show a clear pattern of recurrence at
intervals of 8, 121.5 and 8, 105.5 years.
Transits, Occultation, Eclipse occur when these celestial bodies are in line with
earth. All these are sort of mini eclipse. The orbit of Venus is inclined 3.4° with
respect to Earth's orbit. It intersects the ecliptic at two points or nodes that cross
the Sun each year during early June and December. If Venus happens to pass
through inferior conjunction at that time, a transit will occur. Although Venus's
orbital period is only 224.7 days, its synodic period (conjunction to conjunction) is

2. 583.9 days. Due to its inclination, most inferior conjunctions of Venus do not
result in a transit because the planet passes too far above or below the ecliptic
and does not cross the face of the Sun. When a transit of Venus occurs, a
second one often follows eight years later. This is because the orbital periods of
Venus (224.701 days) and Earth (365.256 days) are in an 8 year (2922 days)
resonance with each other. In other words, in the time it takes Earth to orbit the
Sun eight times, Venus completes almost exactly thirteen revolutions about the
Sun. As a result, Venus and Earth line up in the same positions with respect to
the Sun. Actually, the two orbital periods are not quite commensurate with each
other since Venus arrives at the eight year rendezvous about 2.45 days earlier
that Earth. After the third eight-year cycle, Venus arrives too early for a transit to
occur. The next transit season occurs either 105.5 years or 121.5 years later at
the opposite node of Venus' orbit. Once again, a pair of transits will often occur
separated by eight years. This recurrence pattern of 8 + 105.5 + 8 + 121.5 years
can be seen repeating itself in the catalog of Venus transits. During the six
millennium period 2000 BCE to 4000 CE, Earth experiences 81 transits of Venus
across the Sun. 44 in June at Descending Node & 37 in December at Ascending
Node.
Geocentric Phases of the 2004 Transit of Venus were between 05:13:29 (UT) to
11:25:59 (UT). The 2004 transit of Venus has been used in developing and
testing new techniques and strategies for the detection and characterization of
other extra-solar planets. However, the greatest interest was also in public
outreach and educational opportunities to share this unique event with non-
scientists.
The June-2012 transit will be already in progress as shown in Figure -1, at

3. sunrise for observers in central Asia, including INDIA, the Middle East, Europe,
and eastern Africa, The Sun sets while the transit is still in progress from most of
North America, the Caribbean, and northwest South America. No portion of the
transit will be visible from Portugal or southern Spain, western Africa, and the
southeastern 2/3 of South America. Note that due to the International Date Line
the Western Hemisphere will see the transit on June 5.
Geocentric Phases of the 2012 Transit of Venus will be Contact I at 22:09:38 (for
India 03.40 am), Contact II at 22:27:34 (for India 03.57 am), Greatest at 01:29:36
(for India 07.00 am), Contact III at 04:31:39 (for India 10.02 am) & Contact IV at
04:49:35 (for India 10.19 am). As mentioned above the principal events occurring
during a transit are characterized by contacts. The event begins with contact I
which is the instant when the planet's disk is externally tangent with the Sun. The
entire disk of the Venus is first seen at contact II when the planet is internally
tangent with the Sun. During the next several hours, Venus gradually traverses
the solar disk at a relative angular rate of approximately 4 arc-min/hr. At contact
III, the planet reaches the opposite limb and is once again internally tangent with
the Sun. The transit ends at contact IV when the planet's limb is externally
tangent to the Sun. Contacts I and II define the phase called ingress while
contacts III and IV are known as egress. Greatest transit is the instant of

4. minimum angular separation between Venus and the Sun as seen from Earth's
geocenter. During the 2012 transit, Venus's minimum separation from the Sun is
554 arc-seconds, whereas during the 2004 transit, the minimum separation was
627 arc-seconds. Due to Parallax the ± 7 minutes difference can happen for
contact times.
Kepler made first prediction of Venus transit in 1627, it was about 1631’s event.
French astronomer Gassendi has observed first transit but it was of mercury on
7th November 1631. Immediate event of Venus transit in next month could not be
observed by him as that was not visible from Europe. The first transit of Venus
was observed by British astronomer Jeremiah Horrocks, who discovered the 8-
year pairing of transits that Kepler had missed because he (Kepler) had failed to
account for the size of the Earth in his calculations. William Crabtree was also
with him on 4th December 1639 for observation.
In past many attempts were made to observe transits, for that they visited far off
places. The only way to get to these places was by a long and difficult journey by
wooden sailing ship. Such journeys exposed travelers to considerable mortality
from scurvy, disease, and shipwreck long before you reached your destination.
Despite these difficulties, the importance of measuring the distance from the
Earth to the Sun was such that for the first time in recorded history astronomers
from all over the world collaborated in an international project to measure an
astronomical event. By modern standards, the scale of the enterprise can be
compared to the space program: it required capital outlays from governments,
the cooperation of civilian and military authorities, and a few, brave adventurers
willing to travel far and risk life and limb for a common scientific goal. The
unfortunate Guillaume Le Gentil spent eight years travelling in an attempt to
observe either of the transits. His unsuccessful journey led to him losing his wife
and possessions and being declared dead.
The analysis of the transit data proved to be worth the great price paid by the
astronomers who traveled the world to observe it. In 1771, the French
astronomer Lalande used the combined 1761/1769 transit data to derive a
distance of 153 ±1 million kilometers. The precision was less than Halley's
hoped-for 1 part in 500 or so because of the black drop effect, but still vastly
better than previous estimates. In 1891, the American astronomer Simon
Newcomb using the same data but better analysis techniques derived a distance

5. of 149.7±0.9 kilometers. Subsequent transit observations in the 19th century
were to further refine this measurement. When Newcomb combined the 18th
century data with those from the 1874/1882 Venus transits, he derived a refined
solar distance of 149.59±0.31 million kilometers (a precision of 1 part in 480).
This precision was only rivaled by an alternative technique, the parallax of Mars,
this time measured in 1877 using then-new photographic techniques. All yielded
roughly similar distances. By the mid-20th century, Venus Transits and Mars
Parallaxes were supplanted by radar echolocation and spacecraft Doppler-
telemetry techniques. During the late 20th century, direct radar measurements of
the distances of Venus accumulated over 40 years helped to refine the estimate
of the Astronomical Unit to its modern value of 149,597,870.691±0.030
kilometers. Yes, that is not a typographical error: the AU really is known to a
precision of ±30 meters (roughly the width of an football field).
Indian mathematician, Venkatesh Ketkar also predicted Venus transit of 9th
December 1874. Next transit after 6th June 2012 is of Mercury in 9th May 2016.
An occultation occurs when an apparently larger body passes in front of an
apparently smaller one. A transit occurs when an apparently smaller body passes
in front of an apparently larger one. An eclipse occurs when a body disappears or
partially disappears from view, either by an occultation, as with a solar eclipse, or
by passing into the shadow of another body, as with a lunar eclipse. Transits and
occultations of the sun by Earth's moon are called solar eclipses regardless of
whether the sun is completely or partially covered. The Moon's orbit is inclined to
the ecliptic, any stars with an ecliptic latitude of less than about 6.5 degrees may
be occulted by it. There are three first magnitude stars that are sufficiently close
to the ecliptic that they may be occulted by the Moon and by planets – Regulus,
Spica and Antares. Jupiter was occulted by the Moon on June 7, 2005. In 1959,
Venus occulted Regulus. Uranus' rings were first discovered when that planet
occulted a star in 1977. On the evening of July 2-July 3, 1989, Saturn passed in
front of the 5th magnitude star 28 Sagittarii. Pluto, which was re-designated as a
dwarf planet in 2006, occulted stars in 1988, 2002, and 2006, allowing its
tenuous atmosphere to be studied. It is also possible for one planet to occult
another planet. However, these mutual occultation’s of planets are extremely
rare. The last such event occurred on January 3, 1818 and will next occur on
November 22, 2065, in both cases involving the same two planets—Venus and
Jupiter. Asteroid occultations are useful for measuring the size and position of

6. asteroids much more precisely than can be done by any other means. A cross-
sectional profile of the shape of an asteroid can even be determined if a number
of observers at different, nearby, locations observe the occultation. It is possible
that the moon or another celestial body can occult multiple celestial bodies at the
same time. Such events are extremely rare and can be seen only from a small
part of the world. The last event of such type was on April 23, 1998 when the
moon occulted Venus and Jupiter simultaneously for observers on Ascension
Island. There are only 18 mutual planetary transits and occultations as seen from
Earth between 1700 and 2200.
Details of the Venus :
Diameter : 12104 Kms
Mass : 4.87 x 1024 Kgs
Self Rotations Period : 243 Days (East to West)
Orbital period around Sun : 225 Days
Synodic Period : 584 Days
Distance from Sun : 10,75,00,000 Kms
Maximum Visual Magnitude : -4.4
Observing the Transit - Since the apparent diameter of Venus is nearly 1 arc-
minute, it is just possible to see without optical magnification (but using solar filter
protection) as it crosses the Sun. Eclipse viewing glasses can be used to
observe the transit. Nevertheless, the planet appears to be only 1/32 of the Sun's
apparent diameter so a pair of binoculars or a small telescope at modest power
will offer a much more satisfying view. All binoculars and telescopes must be
suitably equipped with adequate filtration to ensure safe solar viewing. The visual
and photographic requirements for observing a transit are identical to those for
solar viewing. Never look directly at the Sun, especially when using binoculars or
a telescope. Direct sunlight can cause permanent eye damage in seconds. For
safe direct viewing of the Sun, #14 welder's glass can be used, or a proprietary
material known as Solar Screen. The best way to view the Sun with binoculars or
a telescope is by projection, looking at an image of the Sun rather than at the
Sun is relatively safe and, with it, many people can view the Sun at once. Do not
use binoculars whose front lenses are 50 millimeters across or wider. Binoculars
usually are described by a pair of numbers separated by an 'x', such as "7 x 3'' or

7. "7 x 50''; the number to the right of the 'x' is the diameter of the front lenses in
millimeters. Big lenses gather a lot of light, and the heat generated by direct
sunlight in side large binoculars can damage their complex optics.
Lastly, I feel Transit, Occultation, Eclipse, Meteor Shower & similar Celestial
happenings/events are good means for social reform. These demonstrations can
eradicate superstitions related to them & also inculcate scientific temperament
among gullible masses. Everybody should use these opportunities, on personal,
organizational or media level. If you want to watch this transit please contact us.
Please note, the monsoon-cloudy weather may affect the observation.
Regards.
Santosh Takale,
Scientific Officer, BARC
Ph - 0-9967584554.
santoshatbarc@gmail.com
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