... Enjoy the wonders of dark skies

Lunar Occultation of Mars – 10th of May 2008

The Moon is the queen of the night, as in the celebrated poem of Keats to the nightingale –

Already with thee! tender is the night,

And haply the Queen-Moon is on her throne, 

Cluster'd around by all her starry Fays;

The Queen, because Moon is the brightest celestial object in the night. That the queen of the night has a lonely throne is a thought that is subconsciously present in our minds.
Notwithstanding that Keats talks of the Moon ‘clustered around by all her starry fays’, we feel a definite sense of surprise if we see a bright star or a planet located very close to the Moon – an intriguing something happening in the sky.

An event even more intriguing than such a close conjunction between the Moon and a bright star or planet, is a Lunar Occultation – when a star or a planet moves behind the Moon and sometime later, reappears from behind the Moon. Before and after the occultation, there is a view of the Moon and this celestial object close together in the sky, adding to the interest of the event.

A Lunar occultation could be the passing of the Moon in front of any other distant celestial Object – a Planet, other Solar System objects, a distant Star or a deep sky object. Of these, the passage of the Moon in front of the naked eye Planets or bright stars is an event that is most accessible to people without any observing equipment.

A Lunar Occultation of the Planet Mars will take place in the evening of the 10th of May. All of India is very favorably placed, to view this event.

As viewed from Delhi, Mars will be seen to move behind the dark limb of the Moon, at about 7:41 PM and reappear from behind the bright limb, at about 8:44 PM. Moon, at this time, is in an intermediate phase between a thin crescent and a half Moon. When Mars is just reappearing from behind the bright limb of the Moon, it might look like a thick, skewed, ruby ring in the sky, (a lot of gold of the thick crescent Moon and the small ruby which is Mars) which should be interesting to see. As seen from the south - Chennai, for instance, the skew in the ring will disappear, with the ruby placed more towards the centre of the crescent of the Moon.

While a Lunar occultation 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 Mars would be quite an interesting experience. Simply because Mars is reasonably bright and can be easily seen with the naked eyes, 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. Well, for all of India, that is the case – the event happens just after sunset. However, the Northern and western parts of the country will be in evening twilight, when Mars disappears behind the Moon.

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 topography of the Moon. These are wonderful events to watch and have a lot of potential for educational activities.

Nehru Planetarium, New Delhi, will be conducting a public skywatch from the backlawns of the Teen Murti House, to help interested people view the event through telescopes. Amateur Astronomer Ajay Talwar will be setting up his 8 inch computerized GOTO telescope at this location, which would give a view from the telescope projected directly on to a screen, as well as provide a video feed for electronic media channels.

In addition, interested people could also view the event directly through telescopes set up at the Planetarium one of which would be Ajay Talwar’s handmade 20 inch telescope, the largest amateur telescope in India. Members of the Amateur Astronomers Association, Delhi will be present to share with the people their love for astronomy, help those gathered befriend the stars and planets and also participate in the ongoing “Taare Sadak Par” program of quantifying light pollution through simple star counts.

Some members of the amateur astronomers association, will be going to different monuments of Delhi, placing themselves a little to the east of these monuments, zooming in on the Moon, and then capturing this intriguing celestial event against the monumental heritage of Delhi. Some of the members from the Planetarium will be at the Jantar Mantar, using the Jai Prakas instrument of the observatory, to measure the changing angle between the Moon and Mars, following the reappearance of Mars. This particular usage of the Jai Prakas, for measuring angles between celestial objects, is something that does not form the standard utility of this instrument. It can however, be used very simply, for measurements of small angles between celestial objects and this possible usage of the observatory instrument, needs to be highlighted.