Annular Solar Eclipse of 2020 June 21
from Saudi Arabia, Oman, India or Tibet (China)
To observe the 2020 June 21 annular eclipse, I will likely travel to Oman because it’s the perfect choice both for the weather and the beauty of the country or else to the Tibetan plateau where the higher elevations will provide more enjoyable temperatures and a very slightly increased magnitude. Trying to view a deeper and nearly pearled annular, and yet not even close to ASE 1966 in Greece, from the summit of the Hardeol peak (Temple of God) at 7,151 meters (23,461 feet) in India is enticing although the odds of succeeding are far too low because of the extremely high elevation, technical climb challenges, remoteness and pre-monsoon potentially unstable weather; moreover to this date this peak has only been climbed twice. In the end Tibet could be the more balanced option enabling the eclipse chasers to avoid torrid heat and airborne dust, knowing that no matter what the apex/tip of the umbral shadow cone is about 2,300 kilometers above and as such well out of reach. In the end observers in India and Tibet, where the eclipse path is at its narrowest, can nearly expect to have a view quite similar to the one of ASE 1984 across the USA east coast. On the other hand, observers located earlier or later inside the eclipse path will get a slightly lower magnitude and hence a marginally thicker ring. The visual appearance, through solar filters unless near sunrise or sunset, of this deep annular solar eclipse will be similar to the February 1999 annular. Covid-19 Update: because of the novel coronavirus pandemic we were not able to travel abroad and did have to cancel all our plans. In the end only residents of the countries crossed by the path of annularity got to experience this thin ring. Such a shame we couldn’t travel for this unique eclipse! My personal experience was even worse as I was already traveling in Argentina during the mid-March lockdown and had to exfiltrate myself only to be on partial unemployment back in France and two days before the annular laid off with 15% of the staff at the headquarters in a social plan despite a 22-year seniority (as one can imagine the company’s executives just took the opportunity even though there was no reason to act so quickly and without any prior consultation as the state was paying our salaries)!
Average cloudiness in June along the path of annularity (courtesy of Jay Anderson)
Annular eclipse animation
This deep annular eclipse provides lots of excellent viewing opportunities while crossing many interesting regions where the weather is often favorable. Here are a few examples among many others. As we will see later being close to the greatest eclipse point and at higher elevations can prove useful.
Rub al-Khali sand dunes in Oman
Hardeol peak in India (approach from Munsiyari and view from the Milam Glacier)
Prayer wheels on the shores of lake Manasarovar in Tibet with the Gurla Mandhata peak in the background (China)
Here we go for two Baily’s beads simulations, without any solar filter on the left and with on the right. Even though the solar ring is very narrow looking at it naked eye without eclipse glasses is not possible and safe for your eyesight. However photographically speaking quite a few interesting things can be attempted by those who planned it well enough. Those tempted to photograph the chromosphere should get closer to the edges of the eclipse path: the main reason being that the Baily’s beads duration will be increased, at the expense of the annularity duration and/or a symetrical ring but taking the risk is well worth it. Nevertheless the chromosphere can also be imaged from the centerline.
Baily’s beads simulation without solar filter from Lake Manasarovar in Tibet, China (generated by my Solar Eclipse Maestro application)
Baily’s beads simulation with solar filter from Lake Manasarovar in Tibet, China (generated by my Solar Eclipse Maestro application)
And now a comparison of the ring thickness which is telling. One can see that being in Tibet rather than in Oman allows to have a substantially thinner ring. The comparison with the annulars of May 1984 and the more recent of February 2017 helps to understand what can be expected.
Comparison of the 2020 annular ring thickness at two locations with the ones of the 2017 annular and 1984 pearled annular
The magnitude of an eclipse is important, but its obscuration is even more as it’s linked to the greatness of the area covered by the Moon and as such this is the indicator providing the best description of what can be seen. Both the magnitude and obscuration vary along the eclipse path, so choosing your location wisely is possible with the help of the two graphs below. You can notice that maximizing the obscuration can be done by traveling to longitude 81 degrees east, that is the western part of Tibet near the borders with India and Nepal.
The second graph also shows that the high elevation of the Tibetan plateau helps to increase a tiny bit further the obscuration. Above an obscuration of 95%, or about 4 minutes to second contact, the ambient light distribution starts to be different and the decline of its brightness clearly noticeable. At an obscuration of 98%, or about 2 minutes to second contact, the color balance changes radically because the wavelengths contributing to the green and blue plunge while the red component becomes dominant, this effect being related to the solar limb darkening as only the solar limb stays visible.
A few years ago, after carefully studying the chances to succeed in viewing this eclipse from the summit of the Hardeol peak or other peaks around I decided to bail out on it as it wouldn’t have brought much other than taking high risks while this annular could not qualify as a broken or pearled one even at this 7,100 meters (23,300 feet) elevation anyway. That said an observation from the Tibetan plateau does help minimize the risks while at the same time keeping some of the advantages. It’s also an opportunity to visit the site of the Ngari (Shiquanhe) observatory under construction and the western part of Tibet.
Fractional cloud amount in June along the eclipse path around time of annularity (courtesy of Jay Anderson)
Average cloudiness in June over Africa and the Arabic Peninsula (courtesy of Jay Anderson)
Average cloudiness in June over Pakistan, India and Tibet (courtesy of Jay Anderson)
The following pictures were taken in February 1999 and you can see they match the simulations quite well although those were done at low resolution. Observers who wanted to have both a complete ring and a nice display of Baily’s beads had to be well inside the path by about 8 kilometers, the village of Greenough being indeed barely qualified: some of them decided to go a few kilometers to the south to be on the safer side. Beads and chromosphere can be seen on all the pictures that were taken without any solar filter. Note: not using any proper solar filter is not recommended unless you know exactly what you’s doing. If you are not experienced then please DO NOT ATTEMPT this and DO NOT LOOK THROUGH THE VIEWFINDER.
Picture taken without solar filter, about 13 seconds before second contact, by Fred Espenak from Greenough in Western Australia
Picture taken without solar filter, about 12 seconds after third contact, by Fred Espenak from Greenough in Western Australia
Picture taken without solar filter, about 9 seconds before second contact, by Fred Espenak from Greenough in Western Australia
Picture taken without solar filter, about 11 seconds after third contact, by Daniel Fischer from Greenough South in Western Australia
Better pictures can be taken during this deeper annular eclipse. Here is an illustration so that you can know what to expect in terms of ring narrowness.
Thinness of the ring at two locations for 2020 and sample with the deeper one in 1984