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Don’t Miss it… Annular Solar Eclipse of 2020

Ahmedabad: On 21st June 2020, we will be celebrating World Yoga Day, Longest Day for the Northern Hemisphere, and fighting against COVID – 19 pandemic, but on this day we Indian Subcontinent Region are going to observe Annular Solar Eclipse. Last year many of us observed the annular solar eclipse on 26th December 2019, in which the maximum eclipse was visible in the southern part of India. Many people specially travelled from various regions to observe annular solar eclipse only. Nowadays due to COVID – 19 pandemic, many of us cannot travel to watch this eclipse. But don’t worry in most of India we can observe Partial Solar Eclipse.

Eclipse is a game of shadow, in this game one body obscures another body and the observer can’t see one and this event is called eclipse. In general, we know two types of eclipse, Solar Eclipse & Lunar Eclipse. Lunar Eclipse occurs when the Earth Comes between Moon & the Sun, Shadow of the Earth casts on the Moon, hence we can see our mother earth’s shadow on Moon, and we see Lunar Eclipse. Now Solar Eclipse occurs when the Moon comes between the Earth and the Sun, hence a portion of the Sun is covered by the Moon so we can’t see a complete phase of the Sun. This phenomenon is known as Solar Eclipse.

Solar Eclipse can be divided into 4 parts, (1) Total Solar Eclipse (TSE), in which the face of the Moon covers the full face of the Sun. In total Solar Eclipse (TSE) we can see Baily’s Beads, Diamond Ring, Corona kind of features of The Sun & Moon. (2) Annular Solar Eclipse (ASE), in which Moon can’t cover the full face of the sun and moon comes between the Sun, as an observer we can see the ring of fire around the disc of Moon, and Moon will look complete black disc in front of the Sun. (3) Partial Solar Eclipse, in which the Moon will cross in front of the sun but not completely in front of the Sun, Hence it only covers some part of the Sun. In Every Solar Eclipse expecting the line of Maximum areas around that line can observe Partial Solar Eclipse. (4) Hybrid Eclipse, this is a very rare class of eclipse, on the central Eclipse path it appears as TSE and then it changes into ASE, or it starts with ASE and changes into the TSE. This kind of eclipse will occur on 20th April 2023 but will not be visible from India.

How can we see various types of Solar Eclipse? The answer can be given in a very simple way, as we all know, every celestial body revolving around the major body is not in a perfect circle path but an ecliptic path, so sometimes the moon comes closer to the Earth and sometimes it goes further. The furthest point is known as apogee and the closest point is known as perigee. When the moon is on apogee it appears big and when it’s on perigee it looks smaller from the point of observation. The similar way Earth is revolving around the sun in the ecliptic path. When the earth comes closer to the Sun (It happens on 3rd January) the Sun Looks bigger and it’s called perihelion and when the earth will be furthest from the Sun (3rd July) The Sun Looks Smaller. Now if the eclipse occurs at these different conditions, we can see different types of Eclipses.

Annular Solar Eclipse 21st June 2020
The annular phase of the annular solar eclipse of 21st June will start from the Central African Republic in the morning hours and will then proceed to Congo, Ethiopia, Yemen, Saudi Arabia, Oman, Pakistan, India, China, and Taiwan. It will end in the evening in the South Pacific Ocean, as shown on the global map.

On 21 June, only four states of northern India, namely Rajasthan, Haryana, part of Uttar Pradesh, and Uttarakhand will be able to witness the annularity. However, the entire India will witness the partial phase of the eclipse. Annularity will enter India from west Rajasthan, the first town to see it is Gharsana. As per Indian standard time, the first contact will start at 10 hours 12 minutes and 26 seconds. The annularity will start at 11 hours 50 minutes and 08 seconds and will end at 11 hours 50 minutes and 32 seconds, thus making it only 24 seconds of annularity at Gharsana. The fourth and the last contact will be at 13 hours 36 minutes and 56 seconds. The annularity will pass through Anupgarh, Sri Vijaynagar, Suratgarh of Rajasthan, and will enter Haryana from Ellenabad and then progress to Sirsa, Ratia (Fathehabad), Jakhal, Pehowa, Kurukshetra, Ladwa, Yamunanagar to Jagadari and touch upon Behat district of Uttar Pradesh (UP). Behat is the only major town from UP where the annularity will be visible. From UP, annularity enters Uttarakhand and passes via Dehradun, Chamba, Tehri, Agastmuni, Chamoli Gopeshwar, Pipalkoti, Tapowan and finally the annularity will leave India from Joshimath. At Joshimath, the eclipse will start at 10 hours 27 minutes and 43 seconds with first contact and annularity will start 12 hours 09 minutes and 40 seconds and will end at 12 hours 10 minutes and 04 seconds giving rise to only 24 seconds of annularity at Joshimath. The fourth and the last contact will be at 13 hours 54 minutes and 27 seconds.

How to observe?

Like Lunar Eclipse it’s not advisable to suggest watching the solar eclipse with bare eyes. It may harm your eyes and eyesight permanently. We have some safe methods to observe the Solar Eclipse Safely. (We are not suggesting amateurs use telescopes or binoculars for observation even with filters, because anyhow a filter is scratched or used in an unsafe way, your eyes can get permanently damaged.)

Direct methods of observing the solar eclipse safely
Solar filter goggles

o Solar filter goggles offer the easiest and most convenient means of observing a solar eclipse. These goggles are made using approved solar filters in a cardboard frame. It is worn just like ordinary goggles. In case you normally wear spectacles you can mount your solar filter goggles over them. Even while using Safe methods of observing the solar eclipse filters the Sun should not be observed consistently for a long time; look at the Sun through the filters for a while and then look at something else for some time.

Welder’s goggles

o To look at the Sun directly, a number 14 welder’s goggles (very difficult to find number 14 in market) is also a safe alternative. Compared to other devices used for looking at the Sun it can be more easily obtained but is costlier than the solar filter goggles and the Sun appears of unnatural green colour when we see through it. It should be used only as an alternative.

Indirect methods for observing solar eclipse safely
Mirror method

o The mirror method is a good and simple method of observing solar eclipse safely. What you need is just a piece of the circular mirror (about 7.5 cm radius) which you can easily get from a local stationary shop. Throw the image of the Sun on a wall at least one meter away. If you like you can stick the mirror on a ball and keeping it in a bowl filled with sand to form the image of the Sun on a wall or a screen. This is the easiest and the safest way of watching a solar eclipse.

Pinhole projection camera

o If you do not have filter goggles or welder’s glass, then you can make your pinhole camera to see the image of the Sun. Use a cardboard box to make your pinhole projection camera. You may also use two white cardboard pieces for the projection screen. Make a small hole (pinhole) in a piece of cardboard and let sunlight fall on the second piece of cardboard through it; this will form an inverted image of the Sun on the second cardboard. To increase the size of the image, increase the distance between the two cardboards, and to increase the brightness of the image, bring the two cardboards closer. While making a hole in the cardboard, be cautious to keep its size small, or else, you will see the spread of sunlight only in place of the image of the Sun. Remember, seeing the Sun directly through a pinhole may be dangerous; therefore, while using a pinhole camera the Sun should remain at your back. The sunlight from the pinhole of the cardboard passes over your shoulders and forms the inverted image of the Sun on the cardboard screen.

Projection with a telescope

o A small, inexpensive telescope, having no solar filter, can be used to project the image of the Sun on a screen. Turn the telescope till you get the image of the Sun on the screen. Then adjust the distance of the screen to bring the image in focus. Now turn the focussing knob to get a clear sharp image. Extra sunlight coming from the surroundings can be stopped and contrast can be enhanced by placing cardboard in front of the telescope. Looking at the Sun directly through a telescope is dangerous. To project the image of the Sun a small telescope (less than 80mm) should be used, as a large amount of energy collected by it may harm the inner parts of the telescope. The image formed by a telescope will be large, intense and bright as compared to the image formed by a pinhole camera as the telescope collects more light and focuses it better.

What We Can Do During the Eclipse
o It is best to view the reflected or projected image of the Sun.

o Project the image of the Sun on a shaded wall through a hole.

o A small mirror covered with a piece of paper having a circular hole of diameter (1-2 cm) can be used to project the image of the Sun on a shaded wall.

o A small telescope or binoculars can be used to project the image of the Sun on a white card/screen/wall. If binoculars or telescopes have any plastic parts, take necessary precautions to protect them from heating and melting by focussed sunlight.

o Direct viewing of the partially eclipsed Sun should be done only using a scientifically tested filter certified to be safe. A dark welder’s glass (No. 14) is ideal. Use only one of your eyes to view the eclipse. In all cases, please examine the filter before use. A filter with pinholes/scratches must not be used. Don’t touch, fold or wipe the film with your fingers under any circumstances. Any scratch or fold on the film would render it unsafe for viewing the eclipsed Sun.

o During the eclipse, look at the Sun intermittently through safe filters.

Don’ts during the Solar Eclipse
o Don’t attempt to observe the partial or annular phase of any solar eclipse with naked eyes.

o Never look at the Sun through a telescope or binoculars. (In fact, you don’t need these instruments to watch a solar eclipse.)

o Don’t use any filter that simply reduces the visible intensity of the Sun. Fifty-two percent of the Sun’s rays are in the infrared region of the spectrum. This invisible infrared energy predominantly causes damage to the eye.

o Don’t use smoked glass, colour film, sunglasses, non-silvered black & white film, photographic neutral density filters, and polarizing filters. They are not safe.

o Don’t use solar filters normally available with eyepieces of inexpensive telescopes.

o Don’t look at a reflection of the Sun from water.

(Article By Nishant Gor)