On Saturday 14th of April for a brief period of time the Moon will hide Mars behind it. This event will be seen from most of the southern part of India.

The map below shows the area over which the event can be seen.

marsoccult.jpg

Continuous thick white line indicates night-time region
Red line indicates twilight region
Dotted white line is to show daylight region

At the time of the event 16% of the visible disk of the Moon will be illuminated by the sunlight. And the angle between the sun and the moon will be about 48 degrees.

The timings for the event for different locations in India are given below. The times are given in Indian Standard Time (I.S.T.).  Alt below indicates the  altitude above the horizon and negative number indicating below the horizon.

For example, for Bangalore at the beginning of  the event the sun is 9 degrees below the horizon and when Mars reappears from behind the moon the sun will be 6 degrees above the horizon. And the Moon is 33 degrees above the horizon at the beginning of the event.

Az is azimuth, measured in degrees from zero to 360 degrees from north to east to south to west. This is of little importance for a casual observer.

              

                   Disappearance          Reappearance              

                I.S.T.  Sun Moon       I.S.T.  Sun Moon              

Location         h  m   Alt Alt Az       h  m   Alt Alt Az
Amravati         6 10     1 33 119       6 30     6 37 122
Bangalore        5 33    -9 28 109       6 37     6 43 117
Belgaum          5 41   -10 26 110       6 28     1 36 116
Bhubaneshwar     6 08     8 39 124       7 02    21 49 136              

Chennai          6 39    -5 32 111       6 44    10 46 121
Coimbatore       5 29   -11 27 108       6 35     5 42 115
Girawali         5 57    -6 28 114       7 21     0 33 117
Hyderabad        5 52    -3 31 114       6 39     8 41 122              

IUCAA, Pune      5 55    -6 27 113       6 23     0 34 117
Kharagpur        6 15    11 41 127       7 07    23 49 140
Kolhapur         5 36    -8 26 111       7 27     1 36 117
Kolkatta         6 18    13 42 129       7 12    25 50 144              

Madurai          5 28   -10 28 108       6 37     6 44 115
Mangalore        5 32   -12 25 108       6 30     2 38 115
Mumbai           5 58    -7 27 113       6 18    -2 31 116
Mysore           5 32   -11 27 109       6 34     4 41 116              

Nagpur           6 10     3 34 120       6 37     9 40 125
Nanded           5 59    -2 31 116       6 33     6 38 121
Nasik            6 07    -4 29 115       6 15    -2 31 116
Ooty             5 30   -11 27 108       6 34     5 42 115              

Panaji           5 41   -10 25 110       6 27     1 36 116
Puri             6 06     8 39 123       7 03    21 50 137
Vijayawada       5 50    -1 33 115       6 45    12 45 124
Vizag            5 57     3 36 118       6 54    16 48 129

Note:
These timings are based on the coordinates of the place estimated by me and could be in error by about minutes or so.

Summary of the event

We see that Mumbai and Nasik are two stations were the complete event will be seen before the sunrise. For Mumbai the event lasts for about 20 minutes.

Observers in Nasik are very well placed to see this as touch and go event. Nasik is just at the boundary of the northern limit of the event.  Observer in the northern part of the city would see the event as the Moon grazing past Mars but those in the southern part will see Mars being completely covered by the Moon just for a while.

For Amravati, Bhubneshwar, Kolkatta, Nagpur, Puri and Vizag the sun will be above the horizon during the entire event.

As we go south the duration over which Mars will be hidden behind the Moon increases.

Observing the event
The event either takes place before the sunrise or just after it and it should present no difficulty in locating the Moon. The new moon is on April 17th and on 14th the Moon will appear thin crescent.

For most of the places the event takes place at the brighter limb of the Moon.  The image below is drawn for Madurai. D is the point where Mars disappears and it reappears at R.

occult4.jpg

But as we move northwards the points where Mars disappears and reappears also shifts to northwards on the moon.

The image below shows were Mars disappears and reappears for observers in Pune.

occult3.jpg

This is how the Moon would look above the eastern horizon on 14th of March.

occult5.jpg

One could attempt to systematically observe the event.
While you are at it, you could do some systematically record your observations and send those to us for further studies.

Start your observations about half an hour or so before the predicted start of the event for your location.  Look for Mars right below bright lunar crescent.

As the time marches on the gap between the two would decrease gradually. Then Mars and the Moon would be just touching each other. And then in about few tens of seconds (could be as much as 20 to 30 seconds) Mars would be completely behind the Moon.Mars should be visible to the naked eyes but any simple pair of binoculars would be most useful to observe the event and an astronomical telescope will be very useful indeed.

Exactly reverse of this happens for the reappearance but will not be so simple because you will have to kind of guess where would Mars reappear. Also since the event takes place when the sun is above the horizon you will most certainly need an optical instrument to see this.

We would like to know form you

a.  If you could see the disappearance with the naked eyes.
b.  If you could see the reappearance with the naked eyes.
c.  If you could see the reappearance using an optical instrument (binocular or telescope).

Please send your observations in the following format

Occultation of Mars by the Moon
April 14, 2007

Name of the Observer: …………………………………………………………….

Location of the Observer: (town or city)……………………………………………….
(If possible Latitude, Longitude and height of the place of observations.)

Disappearance observed   yes / no
I was observing (check one)

  1. with naked eyes,
  2. using binoculars (give details such as 7×50 etc)
  3. using a telescope (give details of aperture, focal length or f/ratio, eyepiece etc.

—————————-

Reappearance observed   yes / no
I was observing (check one)

  1. with naked eyes,
  2. using binoculars (give details such as 7×50 etc)
  3. using a telescope (give details of aperture, focal length or f/ratio, eyepiece etc.

Send this information by post to

Public Outreach Programme
Inter-University Centre for Astronomy and Astrophysics (IUCAA)
Post Bag #4, Ganeshkhind, Pune 411 007

Or by email to
scipop@iucaa.ernet.in

<about the event please feel free to contact >
Samir Dhurde <samir@iucaa.ernet.in> or Arvind Paranjpye <arp@iucaa.ernet.in>

Last words –

  1. Neither astronomical bodies nor there chance alignments such as this one has any effect on the life on the earth.
  2. Similar event but involving a star Regulus <Magha> takes place on May 23, 07.

Acknowledgement – the occultation timings were computed using Occult Predictions by D Herald of Australia.

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