Lunar Occultation of Venus - November 10^th 2004

(A breathtaking celestial event visible for all of India)

Many would remember the traffic-stopping emergence of Venus from behind the Moon during May, this year.

The event itself had been the occultation of Venus behind the disk of the Moon, in the daytime, and the evening commuters were witnessing the emergence of Venus from behind the Moon – forming a beautiful diamond ring in the western sky.

We have another such event ahead, and, one that is likely to be even more breathtaking than it had been in May, except that one would need to get up early in the morning to view it, on the coming 10^th of November. All of India, can view this event.

If one gets up about 4:30 AM in the morning, on the 10^th of November, and glances towards the east – the sight of Venus eerily close to the thin crescent of the Moon would immediately draw one’s attention towards it – provided the sky near the horizon, a little to the south of East, is clear.

If one is up earlier than this, one may observe the slow movement of Venus closer and closer to the bright crescent of the Moon, until, at about 4:47 AM as seen from Delhi, Venus will disappear behind the bright rim of the crescent, only to reappear an hour later from behind the dark portion of the Moon that is cradled inside the bright crescent. All the phases of this event – the disappearance as well as the reappearance can be seen while the sky is still dark, making this a breathtaking event to watch and start the day with!

The only drawback is that, at the time of the disappearance of Venus, the Moon is a little low in the sky, particularly for the western parts of the country, making the event a little difficult to view, from polluted city skies. The disappearance could easily be a washout, from Delhi – one has to keep one’s fingers crossed as to its visibility from the murky brown skyline of Delhi.

The following are the timings of this event from different cities in India –

The eastern parts of the country are certainly better placed for observing the disappearance of Venus. The minimum altitude required to observe Venus from dark skies is 6⁰, so Mumbai and Ahmedabad regions can, anyway, not see this part of the event. However, even regions that have Altitude of Venus (its angular height above the horizon) near 9 degrees may not be able to have good views of the event, due to city light pollution.

The reappearance will be at better altitudes. The tradeoff being, that the eastern parts of the country will have broad daylight by the time of the reappearance.

During May, this kind of occultation had happened in the evening sky and the people had not been alerted about it, by the Astronomers. And yet, it seemed such an exciting and easy to see event! Why had the Astronomers not alerted everyone about it? The reason was that, the actual event itself – the occultation of Venus, happened in the daytime sky, when it would have been difficult as well as dangerous for anyone to try and spot the crescent Moon and Venus in the sky while the Sun was still above the horizon and located very close to the event. What people saw during May, was simply the movement of Venus away from the Moon, after the event was over and the Sun had set.

While Lunar occultations of Solar system objects is a reasonably frequent event and not very exciting in terms of possible new observations – just the viewing of a Lunar Occultation of Venus would be quite an exhilarating experience. Simply because Venus is so very bright and can be easily seen with the naked eye as it is going behind the Moon – absolutely no equipment will be needed to view such an event – provided it takes place when the Sun is below the horizon.

A little interesting, may also be the differing views of the occultation, as seen from different sites. The views of the disappearance, are reproduced here –

  And here are a few expected views of the re-appearance –

If we look for the times when such an occultation of Venus (the entire event) was visible easily and in dark skies, from India, we find that in the not so recent past – the occultation of Venus in 1980 had been a morning daytime event, though it would have had a reasonable visibility. The 1969 August occultation of Venus would have been spectacular from the western parts of the country. These are not rare events – but, when we put the constraint of easy visibility – they become not-too-freqeunt events. The next occultation of Venus that we could conveniently view, would be on the evening of the 6^th June 2007.

Interesting aspect of the November 10 2004 occultation is the nearness of Jupiter, to Venus. On the 5^th, early in the morning, one could view a very close conjunction of Venus and Jupiter, in the sky. The angular separation between the two being about the angular diameter of the Moon – quite a spectacular conjunction. The last time a spectacular conjunction had been conveniently visible from India, had been during the morning of the 13^th of August 1990 – much more spectacular than the current one. The next convinient Jupiter Venus conjunction to view will only occur on the 18^th of August 2014 AD. Such conjunctions are very frequent – the relative rarity arises only when we look for convinience of viewing such events.

Another factor about the nearness of Venus and Jupiter, during this occultation. The movement of the Moon over the timescale of a day and different angles of viewing results in the non visibility of the occultation of Venus for regions far to the west of India. It is the planet Jupiter which will be seen to be occulted by the Moon as viewed from some parts of the western world – where this will be a daytime event, on the 9^th of November.

There is nothing occult about any of this (so, astrologers need not scramble forward to give out any of their predictions). This event is a simple matter of the apparent movement of a Planet behind the Moon – observed many times in the history and used for the determination of the geography of different regions. Currently, such events do not hold out opportunities of obtaining useful scientific data – but, they are wonderful events to watch and have a lot of potential for educational activities.

Acknowledgements : To the people behind the Astronomy software - Lunar Occultation Workbench, Occult and Redshift.

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