A transit of Mercury over the disc of the Sun will take place in the afternoon of May 9, 2016 (19 Vaishakha, 1938 Saka Era). This transit phenomenon will be visible from India.

This phenomenon takes place when the planet Mercury will be seen as a small black dot travelling from one limb of the solar disc to the other.

From the Earth this phenomenon is seen when the Mercury passes between the Sun and the Earth. This happens only when the Sun, the planet Mercury and

the Earth are lined up in one plane. The Mercury appears as a dot on the solar disc because its angular size is very small compared to that of the Sun as seen

from the Earth.

The transit begins with Contact-I, the instant when the disc of the planet Mercury is externally tangent with the Sun (Ingress exterior) followed by Contact-II

when the Mercury is internally tangent with the Sun (Ingress interior). The Mercury will be seen as a black spot, traveling several hours over the face of the disc,

will reach the opposite limb of the Sun at Contact-III, when the disc of the planet Mercury is internally tangent with the Sun (Egress interior). Finally,

the transit ends at Contact-IV when the disc of the planet Mercury is externally tangent with the Sun (Egress exterior).

The phenomenon is a relatively rare one which occurs 13 or 14 times in a century. It occurs in the month of May and November. The interval between

one November transit and next November transit may be 7, 13 or 33 years whereas the interval between one May transit and the next May transit may be 13 or 33 years.

The transit of Mercury will be visible from most of Asia (except south eastern parts and Japan), Europe, Africa, Greenland, South America,

North America, Arctic, North Atlantic Ocean and most of the Pacific Ocean. The entire transit, from beginning to end, will be visible from eastern

North America, northern South America, the Arctic, Greenland, extreme northwestern Africa, western Europe, and the North Atlantic Ocean.

In India, the beginning of the event comprising of Ingress exterior (Contact-I) and Ingress interior (Contact-II) will be visible from all places. The duration of the

entire transit event will be about 7 hour and 30 minutes. The observer in India will not see the ending of the event as the same will be in progress after sunset.

Depending upon the sunset time of different places in India, the observer located in the extreme east of the country will see the event about 1 hour from

the beginning and the observer located in the extreme west of the country will see the event about 2 hours and 45 minutes from the beginning.

 

In Delhi, the event can be seen for a duration of about 2 hours 20 minutes as it will start at 16h 41m IST and sunset will take place at 19h 01m IST.

Similarly, in Kolkata the event will start at 16h 41m IST and it can be seen for a duration of about 1 hour 26 minutes, in Mumbai the event will start

at 16h 41m IST and it can be seen for a duration of about 2 hours 24 minutes, in Chennai the event will start at 16h 41m IST and it can be seen for a

duration of about 1 hour 45 minutes.

A table related to local circumstances of some places in India is appended below for ready reference.

LOCAL CIRCUMSTANCES RELATING TO CERTAIN PLACES IN INDIA

 

Place	Ingress Exterior contact	Ingress Interior contact	Egress Interior contact	Egress Exterior contact	Sunset	Duration
	h      m    s	h      m    s			h   m	h   m
Agartala	16   40   33.6	16   43   45.6	**   **	**   **	17   57	1   16
Ahmedabad	16   40   45.5	16   43   57.0	**   **	**   **	19   12	2   31
Aijawl	16   40   33.1	16   43   45.1	**   **	**   **	17   52	1   11
Ajmer	16   40   45.3	16   43   56.9	**   **	**   **	19   09	2   28
Allahabad	16   40   39.5	16   43   51.3	**   **	**   **	18   39	1   58
Amritsar	16   40   48.4	16   44   00.1	**   **	**   **	19   17	2   36
Bangalore	16   40   37.8	16   43   49.4	**   **	**   **	18   37	1   56
Bhagalpur	16   40   36.5	16   43   48.4	**   **	**   **	18   18	1   37
Bhopal	16   40   41.4	16   43   53.1	**   **	**   **	18   53	2   12
Bhubaneswar	16   40   34.5	16   43   46.3	**   **	**   **	18   15	1   34
Cannanore	16   40   39.5	16   43   51.0	**   **	**   **	18   44	2   03
Chandigarh	16   40   46.2	16   43   57.9	**   **	**   **	19   06	2   25
Chennai	16   40   35.8	16   43   47.4	**   **	**   **	18   26	1   45
Cochin	16   40   38.5	16   43   49.9	**   **	**   **	18   37	1   56
Cooch Behar	16   40   35.9	16   43   47.9	**   **	**   **	18  0 9	1   28
Cuttack	16   40   34.5	16   43   46.3	**   **	**   **	18   15	1   34
Darjeeling	16   40   36.9	16   43   48.9	**   **	**   **	18   15	1   34
Dehradun	16   40   45.0	16   43   56.7	**   **	**   **	19   01	2   20
Delhi	16   40   44.4	16   43   56.1	**   **	**   **	19   01	2   20
Dibrugarh	16   40   34.7	16   43   46.8	**   **	**   **	17   48	1   07
Dwarka	16   40   48.3	16   43   59.7	**   **	**   **	19   24	2   43
Gandhinagar	16   40   45.5	16   43   57.0	**   **	**   **	19   12	2   31
Gangtok	16   40   36.9	16   43   48.9	**   **	**   **	18   14	1   33
Gaya	16   40   37.2	16   43   49.0	**   **	**   **	18   25	1   44
Guwahati	16   40   35.0	16   43   47.0	**   **	**   **	18   01	1   20
Haridwar	16   40   44.7	16   43   56.4	**   **	**   **	19   01	2   20
Hyderabad	16   40   38.2	16   43   49.8	**   **	**   **	18   39	1   58
Imphal	16   40   33.3	16   43   45.3	**   **	**   **	17   49	1   08
Itanagar	16   40   35.0	16   43   47.1	**   **	**   **	17   54	1   13
Jaipur	16   40   44.6	16   43   56.2	**   **	**   **	19   05	2   24
Jalandhar	16   40   47.8	16   43   59.4	**   **	**   **	19   13	2   32
Jammu	16   40   49.2	16   44   00.9	**   **	**   **	19   19	2   38
Kanyakumari	16   40   37.4	16   43   48.9	**   **	**   **	18   31	1   50
Kavalur	16   40   36.7	16   43   48.2	**   **	**   **	18   31	1   50
Kavaratti	16   40   41.8	16   43   53.2	**   **	**   **	18   53	2   12
Kohima	16   40   33.7	16   43   45.8	**   **	**   **	17   49	1   08
Kolkata	16   40   34.2	16   43   46.0	**   **	**   **	18   07	1   26
Kozikode	16   40   39.2	16   43   50.7	**   **	**   **	18   42	2   01
Lucknow	16   40   40.8	16   43   52.6	**   **	**   **	18   44	2   03

 

“** **” indicates the event occurs after sunset.

 

LOCAL CIRCUMSTANCES RELATING TO CERTAIN PLACES IN INDIA

 

Place	Ingress Exterior contact	Ingress Interior contact	Egress Interior contact	Egress Exterior contact	Sunset	Duration
	h      m    s	h      m    s			h   m	h   m
Madurai	16   40   36.9	16   43   48.4	**   **	**   **	18   30	1   49
Mangalore	16   40   40.3	16   43   51.7	**   **	**   **	18   48	2   07
Mount Abu	16   40   46.0	16   43   57.6	**   **	**   **	19   14	2   33
Mumbai	16   40   43.6	16   43   55.1	**   **	**   **	19   05	2   24
Murshidabad	16   40   35.1	16   43   47.0	**   **	**   **	18   10	1   29
Muzaffarpur	16   40   37.7	16   43   49.6	**   **	**   **	18   25	1   44
Mysore	16   40   38.6	16   43   50.0	**   **	**   **	18   40	1   59
Nagpur	16   40   39.1	16   43   50.7	**   **	**   **	18   42	2   01
Nasik	16   40   43.2	16   43   54.7	**   **	**   **	19   03	2   22
Panaji	16   40   41.5	16   43   53.0	**   **	**   **	18   55	2   14
Patna	16   40   37.4	16   43   49.3	**   **	**   **	18   24	1   43
Pondicherry	16   40   36.0	16   43   47.5	**   **	**   **	18   27	1   46
Port Blair	16   40   28.7	16   43   40.6	**   **	**   **	17   35	0   54
Pune	16   40   42.6	16   43   54.1	**   **	**   **	19   00	2   19
Puri	16   40   34.2	16   43   46.0	**   **	**   **	18   14	1   33
Raipur	16   40   37.4	16   43   49.2	**   **	**   **	18   33	1   52
Rajkot	16   40   46.9	16   43   58.3	**   **	**   **	19   18	2   37
Ranchi	16   40   36.1	16   43   48.0	**   **	**   **	18   20	1   39
Shillong	16   40   34.5	16   43   46.5	**   **	**   **	17   59	1   18
Shimla	16   40   46.2	16   43   58.0	**   **	**   **	19   06	2   25
Silchar	16   40   33.6	16   43   45.7	**   **	**   **	17   54	1   13
Siliguri	16   40   36.5	16   43   48.4	**   **	**   **	18   13	1   32
Silvassa	16   40   43.7	16   43   55.2	**   **	**   **	19   05	2   24
Srinagar	16   40   50.4	16   44   02.1	**   **	**   **	19   22	2   41
Sringeri	16   40   39.7	16   43   51.2	**   **	**   **	18   46	2   05
Tamelong	16   40   33.6	16   43   45.7	**   **	**   **	17   50	1   09
Thanjavur	16   40   36.2	16   43   47.7	**   **	**   **	18   27	1   46
Thiruvanantapuram	16   40   38.1	16   43   49.5	**   **	**   **	18   34	1   53
Udaipur	16   40   45.1	16   43   56.7	**   **	**   **	19   10	2   29
Ujjain	16   40   42.8	16   43   54.4	**   **	**   **	18   59	2   18
Vadodara	16   40   44.4	16   43   55.9	**   **	**   **	19   07	2   26
Varanasi	16   40   38.5	16   43   50.3	**   **	**   **	18   32	1   51

 

“** **” indicates the event occurs after sunset

 The last transit of Mercury occurred on 6 November, 2006 when just end of the event was visible from the extreme north eastern parts of India at the time of

sunrise.  The next transit of Mercury will take place on 11 November, 2019 but the event will not be seen from India as the same will begin after the sunset

time of all places in India. The transit of Mercury on 13 November, 2032 will be visible again from India.

 

The apparent diameter of Mercury will be nearly 12 arc-second which is 1/158 of Sun’s apparent diameter. Thus, it will be difficult to see the Mercury at

transit over the face of the Sun without optical magnification. This event can be viewed with the help of binocular or telescope attached with proper solar

filter or by making projection of the Sun’s image on a white board by telescope. The Sun should never be viewed with the naked eye. Safe technique to

observe is by using filter like aluminized mylar, black polymer or welding glass of shade number 14.