The total solar eclipse, which occurs when the Moon covers the entire visible surface of the sun, is undoubtedly a unique occurrence in life. Not surprisingly, all the attention generated by this phenomenon happens today, 21 August.
Unfortunately for anyone who is in Portugal, there will be little to see, since its beginning coincides with our sunset. The Lisbon Astronomical Observatory (LAO) estimates that about 19% of the covert surface, scheduled to begin at 19:45.
In Madeira and the Azores this figure rises to 33% and 28% respectively, and in the Azores, will also be the place in Portugal where the eclipse will be visible for a longer time, starting at 18:40.
However, the Observatory warns of the risks to the human eye from a longer observation of the sun. The sunglasses are not adequate or sufficient protection, and one should never look at the sun for more than a few seconds. More fundamentally, it is “the use of sunscreens to protect the eyes (eye filters) or equipment suitable for observing solar eclipses, it is absolutely imperative. These specialized filters drastically reduce all solar radiation: ultraviolet, visible and infrared”, advises the LAO.
Only through them can one observe a well-defined luminous solar disk, however, it should not make a continuous observation of the sun even using the sunscreens. The physical characteristics of these filters translate into a transmittance of less than 0.003% in the visible band and less than 0.5% in the next IV. If you wear glasses, you should wear sunscreens prior to this and do not strain your eyes. Not having the right means is preferable to “give up direct observation and resort to projection observation, which enhances the image and provides a safe and comfortable view”.
So, you can look at it from time to time, but the best thing is to look at the phone. This is because NASA, through its application, will transmit the entire eclipse from the most spectacular points to the effect: in the ground, in balloons or planes, and even the International Space Station. In the site that the American agency created, you can see everything, read everything, and find the link to the various NASA applications.
There are other places where you can also follow the phenomenon, such as the Smithsonian Institute, the important thing is not to lose the eclipse, but in total safety.