The Indian eclipse, 1995J. Brit. Astron. Assoc., 106, 1, 1996
The Indian eclipse, 1995Short reports by BAA members in India on 1995 October 24.
October 24, 6.30 a.m... The low red Sun terminates the cold clear dawn over the Mughal city of Fatehpur Sikri in the Indian state of Uttar Pradesh. Together with two other coach-loads of the Explorers Tours eclipse party, we have just arrived from nearby Agra. The other half of the group have had no sleep: for those shadow-chasers, a bone-shaking overnight coach ride from Jaipur, Rajasthan. For 14 years the personal palace-city of the emperor Akbar, but abandoned in 1585 either through lack of water or for military reasons, Fatehpur Sikri ('City of Victory') is a perfectly preserved time-capsule. Its red sandstone buildings are strikingly beautiful. Four hundred years later its main inhabitants are tourists. In an illustrated Guide to Delhi, Agra and Jaipur Louise Nicholson does not exaggerate when she writes 'the hawkers between palace and mosque are some of India's most insistent.' Having fought off droves of them on our reconnaissance yesterday afternoon, today we find the eclipse to be on our side. The Festival of Lights, Diwali, is celebrated today, and the eclipse is bad luck to Hindus. Most of the souvenir-sellers have stayed at home; the remaining stalwarts have swapped the ubiquitous hand-carved elephants for pieces of Mylar and refreshing bananas.
We carry our equipment to a terrace overlooking a relatively empty part of the site, in the caravanserai north-west of the great mosque. Someone has camped here overnight. Flocks of chattering birds swoop over the towers and minarets, offering the chance to snap them in silhouette against the Sun. Beneath us a party of Japanese cause the only friction of the morning: their armed guards will not let us join them on the parched lawn. It is nearly first contact. The sky is beautifully clear, and there is no wind. With no cloud in sight either, spirits are high, our antisocial neighbours quickly forgotten.
The local time is 7.25 a.m. There is a little bite out of the top of the Sun at about 'one o'clock'. My first total eclipse is on time – of course! My immediate companions include Martin Mobberley and John Mason. A few yards further left are Hazel and Brian McGee, Nick Hewitt, David Graham, Don Miles and Stewart Moore. Bruce Hardie had written to me that there could be a limb prominence associated with a sunspot group on the SW limb, as it had earlier shown prominence activity on the SE limb.
With 30 minutes to go the circling birds acknowledge the declining light by their excitement. It is an eerie half-light, but the sharp shadows contradict any impression of approaching dusk. The slits between our fingers cast crescents on the old sandstone walls behind us. By 8.15 there is a distinct chill to the air.
It is now 8.34 a.m. 30 seconds to go, and all Mylar filters are off. Excited cries that the inner corona and chromosphere are already clearly visible. Near the horizon the sky changes from blue through yellow to brown. I sacrifice a binocular view of Baily's Beads to soak up the racing velvet shadow with the naked eye. As the cloak of darkness rushes over, the multiple beads are just winking out, and I go through my programme, ignoring the American TV crew who have just raced up the steps to the terrace, one of whom seems intent in wrapping his electrical cable around one of my tripod legs, another deciding to change his camera battery at the last moment. Venus has long been apparent, low in the east, but there is no time to look for stars and other planets.
The Sun has turned into a steel engraving. A black disk surrounded by a broad and unexpectedly brilliant ring of pearly white light: the inner corona. The surrounding sky is a very dark blue. Within the ring of light, and showing a few spiky prominences, the still more brilliant red chromosphere. But there are no substantial prominences, and my best views of them will come from a later inspection of my colour slides. Outward from the Sun, the corona's brightness rapidly dwindles. It is a fine 'solar minimum' corona, its long axis almost vertical, quite within the 5° field of my 10×50s: I estimate that it reaches 2˝ solar diameters west of (above) the Sun and 3˝ diameters east of it. The outer corona, ghostly and also pearly white, shows a layered structure as if painted upon the sky with an artist's palette knife. The tapering lower half shows little structure, but the top half shows much detail including two unequal extensions. The north and south poles of the Sun are marked by superb long, bright, polar brushes, about equally prominent along each limb.
I have a 400mm telephoto lens on my SLR camera, and 50 ISO Fujichrome Velvia film. Everything has been tried out on the last Full Moon. What was the routine? It is hard to tear myself away from the binocular view. One second at F/11 for the corona. Repeat for luck. Quickly! Change to 1/125s (six clicks anticlockwise) for the prominences! More precious seconds tick away.
As I raise my glasses again the Sun breaks though at '10 o'clock', but it happens in three places simultaneously, each of which exhibits fine structure, before the glowing points finally merge, as three rapid 1/125s shots later confirm. The Diamond Ring is magnificent, sparkling, lingering..... the air is filled with the sound of hundreds of clicking cameras. Never have so many shutters been fired simultaneously! A wave of applause sweeps across us, chasing the retreating shadow. Did we really have 45 seconds? Video playback says we did.
As the light returns we look for shadow bands on a sheet thrown against the wall: they do not seem to be visible. I make a rapid naked eye sketch from memory of the corona's extent. Later the photos all turn out superbly well, but, as expected, none show the full east–west extent of the corona. The final partial phase is largely ignored, as we swap impressions, Martin interviewing us with his video camera. The morning rapidly becomes hotter, and the eclipse-chasers evaporate from the squares, terraces and towers. By fourth contact we are almost all resting in our air-conditioned buses, ready to close the second side of our 'Golden Triangle' tour of Delhi, Agra and Jaipur.
Weeks later, the above impressions still remain engraved upon my mind. Whatever the eclipse lacked in duration was more than compensated for by the sublimity of the corona and the crystal clarity of the sky. What a good investment that new strong tripod turned out to be; and how fortunate that we had moved the BAA AGM forward a week!
From my improvised sleeping place between the video cameras and the telescopes, I could open my eyes at times and verify that the beautiful sky was still above me: the Milky Way, the Pleiades, Orion, Taurus... a few orionids and... no clouds nor wind at all! Clear indication that we would witness once more the most spectacular of events.
Finding this strategic observing platform was quite an adventure. We spent a couple of days looking for accessible hilltops in the area and this brought us into close contact with the small communities of Rajasthan. Sanjeev our driver quickly picked up the relevant aspects of a total solar eclipse and was able to describe them to the villagers, especially to the smiley young children that welcomed us everywhere. But why were we there? Why did we travel (yet again, as many other eclipse chasers have done for decades) all those thousands of kilometers to set up our delicate and heavy equipment on the top of a hill, in the middle of a tiger reserve?
Dawn! Time to get up. The cameras needed a final adjustment once the Sun was above the horizon. Our young friends from the surrounding farms gathered behind us in respectful silence and listened to the instructions from Sanjeev, who would show them (using special safety filters) the advance of the moon over the solar disk.
Alberto Levy and his wife Nomi (friends who came all the way from California) would use a double telescope to obtain pictures of the lower atmosphere of the Sun and also of the extended corona. They would also operate a video camera. I was still adjusting the three video cameras on the motorized mount when Nomi shouted; contact! Just over one hour after sunrise, the moon's disk started to cover the Sun. I finished with the video cameras and then verified that the images in my other two telescopes were centered and in focus. Carlos would operate the high-resolution telescope to obtain detailed views of the Baily's Beads and the chromosphere. I was using another telescope to record the corona in its widest extension, and Peter Beer was ready with the panoramic camera to record the advance of the moon's shadow over the darker and darker landscape, so spectacular from our hill.
A few minutes to totality. A gentle and cold breeze seemed to anticipate the great event. A poor disconcerted eagret flew twice around us and finally went following a random path. Then we found out why were we there. In seconds, the moon's shadow precipitated over the area. I carefully removed the filters from all our equipment and the spectacle was beyond any description: beautiful pearls of bright light were still permeating through the deep valleys in the moon's limb. The electric-pink chromosphere added its colour to the scene. And then, as many observers have described before, a majestic white flower opened in the deep blue sky: like the hair of a beautiful woman floating in the wind, the otherwise powerful and blinding Sun now displayed its delicate corona. A lot of concentration was needed to overcome the emotions triggered by the view through the camera and be able to take special care in centering the image avoiding any vibrations.
This time totality lasted for only 44 seconds, after which the bright pearls produced another cosmic ring of diamonds and the immaculate flower vanished behind the blinding light of the solar disk. In those valuable seconds we obtained excellent graphic and video material. The pictures of the corona show intricate details, thanks to a special technique of radial compensation of luminosity implemented in one of the telescopes. The study of these features will allow a better understanding of the processes involved in the transfer of energy from the solar surface to the corona. Together with the video tapes, the pictures will also be used in TV documentaries and school programs on science.
(For more details of Diego's team's radial compensation technique for imaging the corona, and the spectacular result from India, see the report of the BAA Christmas Meeting in the April Journal!)
Diamond ring at third contact, 1995 October 24, Kalpi, India. 150mm f/6 Newtonian, 1/30 sec., Kodak Tri-X 400 film. (P. Devadas). 65 Kb
I set up my observation site at Kalpi in North India, at longitude 79° 44' E and latitude 26°7' N, falling on the central line of the path of totality. I headed a five member team and our location was on the top terrace of a two-storey Government building, overlooking the banks of the great Indian river, Yamuna, with an uninterrupted view of the sky. I had set up a 150mm dia. f/6 Newtonian telescope with a 35mm camera and filter attachment, and also a 100mm f/6.5 Newtonian for projection and for direct viewing during totality. These were polar aligned the previous night.
The weather was very good with the sky absolutely clear. The whole series of events took place almost as per the predicted times. The Diamond Ring effects just a second before totality and again after totality were spectacular, as the brilliant beam of sunlight flashed through the valleys of the moon's undulating limb. When the thin crescent of the solar limb was narrowing, there appeared a thin dark projection across the vanishing thin horn on the southern end, which seemed to be a lunar high point jutting out. Many reported having noticed this. Just before the first flash of the Diamond light very faint light and dark shadow bands of about 30cm width were observed wavily moving on the terrace from about north-west to south-east, synchronising with the movement of the Moon's shadow over the land.
The total phase was the greatest spectacle with coronal streamers flashing all around the Moon's limb. As expected during the current period of minimum sunspot activity, the equatorial streamers were much longer, with pointed ends. The chromosphere was brilliant with a reddish tint mixed with yellow all round, and a few flares projecting out of the photosphere. The coronal plumes on the north and south polar regions were shorter and curved reminiscent of magnetic poles.
Since the corona was brilliant, it was not exceptionally dark during totality. The planet Mercury was seen above the Sun and Venus much below. It was also found that the duration of totality lasted only for about 55 as against the predicted 61 seconds; this may be due to the fact that Kalpi lies slightly south of the central line of the path of totality.
The visitors who had gathered there were mostly equipped with viewing filters, and observed the coronal streamers during totality with the naked eye and without any filtering aid as advised by us. They appreciated the splendour, beauty and importance of the celestial phenomenon. The public awareness of this rare occurrence was greater than that during the total solar eclipse on 1980 February 16 in India, which was also observed by me.
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