Total Solar Eclipse of 2016 March 8-9
Baily’s Beads Observations and Simulations
The point of greatest eclipse (totality phase during 4 min 9 sec) was located in the middle of the Pacific Ocean east of Indonesia where about 10 million people lived inside the totality path. To observe the 2016 March 8-9 total solar eclipse, I proposed tours only in eastern Indonesia, in the Northern Maluku, where the ground weather prospects were the best and the duration the longest. However the local infrastructure was fairly limited. The Woleai atoll, belonging to Micronesia, was offering the longest land-based duration very close to its maximum but its airstrip was out of order so the logistics would have been far too complex. There were numerous viewing locations along the path, however paying close attention to the weather patterns and local terrain topography was mandatory unless you were on a cruise ship in the Pacific Ocean where the sky was usually clearer. Moreover the 2015-2016 El Niño episode did somewhat improve the weather prospects in Indonesia.
The Baily’s beads simulations were all generated with my Solar Eclipse Maestro application. The goal is to compare actual pictures with simulations all along the path of totality and see how well they match or not. Usually analyzing a series of images is easier because the exposures allow to distinguish individual beads contrarily to videos that are often too saturated.
Lets take the first location in Palembang, Sumatra where the sky was mostly cloudy during totality. Shahrin Ahmad from Malaysia did manage to get a sufficiently good video at second and third contacts.
Baily’s beads simulation seven seconds before second contact from Palembang, Sumatra, Indonesia (video by Shahrin Ahmad)
Baily’s beads simulation 1.2 second after third contact from Palembang, Sumatra, Indonesia (video by Shahrin Ahmad)
In both cases we can conclude we have an excellent and stricking match.
We now move east to the island of Belitung where a German, Robert Wagner, imaged third contact.
Baily’s beads simulation 3.2 seconds after third contact from Belitung, Indonesia (photos by Robert Wagner)
Baily’s beads simulation 3.6 seconds after third contact from Belitung, Indonesia (photos by Robert Wagner)
Again a good match where you can see that even small evolutions in the beads are picked up.
Now lets move to Pulo, Sulawesi where Salamon András succeeded in shooting a series of images at second and third contacts.
Baily’s beads simulation at second contact from Pulo, Sulawesi, Indonesia (pictures from Salamon András)
Pictures by Salamon András in Pulo, Sulawesi
Baily’s beads simulation at third contact from Pulo, Sulawesi, Indonesia
Again we have a perfect match.
Now lets move 40 kilometers (25 miles) south of Palu, Sulawesi, near the centerline where Paul Coleman could photograph Baily’s beads at second contact.
Baily’s beads simulation four seconds before second contact from Pakoeli, Sulawesi, Indonesia (photo by Paul Coleman)
Again we can see that the simulation is identical to the picture.
Now lets move another 350 kilometers (220 miles) down the eclipse track to Luwuk, Sulawesi, south of the centerline where Yu Jun recorded a magnificient series of Baily’s beads at second and third contacts. This composite image won the first prize at the Royal Observatory astronomy photographer 2016 competition in the "Our Sun" category.
Composite by Yu Jun in Luwuk, Sulawesi
Baily’s beads simulation from the south of Luwuk, Sulawesi, Indonesia
Once again we have a perfect match in both the shape and position of the beads.
Now lets move to the Keraton Palace in Ternate where Jacques Guertin photographed third contact.
Baily’s beads simulation five seconds after third contact from Ternate, Indonesia (photo by Jacques Guertin)
Once more the simulation is identical to the picture.
Now lets move to Pulau Mia, Halmahera Timur where I did a small sequence at second contact.
Solar eclipse and actual Baily’s beads around second contact with their simulations from Pulau Mia in the Buli Bay
Again it matches.
Lets move a bit further east again and further away from the centerline with the Norvegian Morten Ross on Pulau Sajafi, Halmahera Timur. The full frame DSLR used was a Nikon D4 equipped with a GPS module which allowed to record accurately both the position and time the pictures were taken at.
Baily’s beads simulation slightly over two seconds before second contact and seven seconds after third contact from Pulau Sajafi, Halmahera Timur, Indonesia (photo by Morten Ross)
Once again it matches perfectly at every level including the predicted totality duration with an estimated error of only two tenths of a second.
Lets move again and this time closer to the centerline with the Romanian Catalin Beldea in Tomalou on Pulau Tidore, North Molucca.
Baily’s beads simulation slightly over three seconds before and after second and third contacts from Pulau Tidore, North Molucca, Indonesia (photo by Catalin Beldea)
Once again a good match, including with the three minutes and nine seconds time difference between the two pictures.
We can now clearly say Baily’s beads can be predicted well in advance and the corrected contact timings are correct. Nevertheless there is one more important thing that must be adjusted from its current standard value, the solar radius; more on this later…