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Astronomical admirers across the kingdom snapped pictures of the start of a rare phenomenon last Friday, featuring three eclipses within the span of one month, as the Covid-19 crisis forced them to observe from the safety of their homes instead of meeting to collectively experience the event.
The sandwich of eclipses, which started with a penumbral lunar eclipse from 8:45pm last Friday evening to 12:04am on Saturday, is scheduled for a solar eclipse on June 21 from 7:14am to 10am , followed by a second penumbral lunar eclipse on July 5 from 6:07am to 8:52am.
According to Dr Waheeb Al Nasser, chairman of the Bahrain Astronomical Society (BAS) and vice-president for academic programs and higher studies at the University of Bahrain, this phenomenon happens roughly every five or so years with the next one slated to occur in 2027.
Unlike a total and partial eclipse, during a penumbral lunar eclipse, the sun, earth, and the moon are imperfectly aligned and the earth blocks some of the sun’s rays on their way to the moon, covering part of the moon with its shadow, also known as the penumbra.
Since the penumbra shadow is much lighter than the umbra during a total or partial eclipse, the phenomenon is difficult to decipher from a regular full moon.
Dr Waheeb said: “Most people did not notice the difference between the two, but we had a number of people take pictures through the eclipse and compare them to see the penumbra of the earth’s shadow.
“Normally, when such phenomenon occur, like the annular solar eclipse late last year, we gather, so that we can answer questions and help people learn more about the science behind the event. But this time, due to the social distancing guidelines, everyone stayed home and shared their photos via social media. My grandson, with whom I usually observe the eclipses, watched it from his house and sent me some photos.”
Photographing the eclipses is its own interesting challenge, as the two have very different considerations.
With a penumbral lunar eclipse, the challenge is allowing just enough light to ensure the moon is visible while also ensuring not too much light enters the lens, so that differences between the phases is clear.
Professional astronomical photographer Ali Namdar suggests using a high shutter speed and low ISO to capture a shot of a full moon, while dramatically decreasing the shutter speed and increasing the ISO to capture an eclipse. Adjustments also have to be made to account for atmospheric and humidity changes so the picture is as clear as possible.
The next eclipse on June 21 is going to be the annular solar eclipse, observable as a partial solar eclipse in Bahrain at its 8:30am peak.
Unlike the “ring of fire” solar eclipse that occurred at the end of 2019, this one will be only observable as a partial solar eclipse in Bahrain. However, it is still crucial that people do not stare directly at the eclipse for more than a second without protective eye wear.
Ali added: “Photographing this requires a solar filter for your lens, without which your camera sensor can be badly damaged. Start off with a high aperture setting, ideally above f/8 and a low shutter speed, increasing it as the sun moves above the horizon.”
BAS, which has supplied over 60,000 pairs of eclipse glasses over the last 20 years, has a limited supply which can be requested by contacting the physics department at the University of Bahrain or members of BAS.
To learn more about the Bahrain Astronomical Society and how you can experience the next solar eclipse on June 21, contact bah.astro.society@gmail.com
