What is interesting about the partial solar eclipse on October 25

For three years in a row, the Moon partially covers the Sun for Ukrainian observers. The first of this series was an annular eclipse on June 21, 2020, small partial phases of which (up to 20%) were observed almost throughout our country. Less than a year later — on June 10, 2021 — the next annular solar eclipse occurred in the Northern Hemisphere, the “echo” of which was also visible in Ukraine. But even then, the Moon here obscured no more than 20% of the diameter of the solar disk. The eclipse expected on October 25 of this year will be neither total nor annular: in the entire visibility zone it will look like a partial one. Despite this, we will be able to see it with phases of more than 50%, which will be the largest indicator in the last 7 years.

During partial solar eclipses, the axis of the cone of the moon’s shadow, that is, an imaginary straight line passing through the centers of the Sun and Moon, does not intersect the earth’s surface. Accordingly, the lunar shadow does not fall on the Earth either — an area of space from where the solar disk looks completely closed by our natural moon. But there is still a penumbra, in which the Moon covers our luminary only partially. Its cone is gradually expanding and has a large enough size, so it “covers” a much larger area of the earth’s surface. 

Scheme of a partial solar eclipse

Most partial eclipses have not very large phases. The territories from which they are visible are also, in general, relatively small and “gravitate” to the northern or southern Arctic Circle. In this sense, the eclipse of October 25 will be a pleasant exception. Its visibility zone extends almost to the equator, and the maximum phase value will be 0.861. It will be observed at sunset at a point with coordinates 61.6° Northern latitude and 77.4°  East longitude, near which the Russian city of Nizhnevartovsk is located. 

In one phase or another, the blackout will be visible in almost all of Europe (including the UK, Ireland and Iceland, but without Portugal and southwest Spain), in northeast Africa and Western Asia, including India, Nepal and Sri Lanka. In Ukraine, it will begin after 12.00 p.m. UTC+3 and in most of its territory it will end by 03:00 p.m. At the moment of the maximum phase, the Sun will be at an altitude of 25° above the horizon (Chernihiv) to 31° (south of the Odesa region).

The visibility zone of a partial solar eclipse on October 25, 2022. There is no eclipse outside the outer red contour. Source: Baader Planetarium

The largest phase on the territory of Ukraine (0.692) will be observed in the east of the Luhansk region. Of the unoccupied territories, the northernmost point of the Kharkiv region will be the luckiest — there the Moon will cover the solar disk by 67.5% of its diameter. The smallest maximum phase of the eclipse (less than 0.5) will be seen by residents of the western part of Transcarpathia.

As practice shows, at a phase of more than 0.6, a slight decrease in the level of illumination of the landscape is already noticeable, and at 0.7 it becomes quite noticeable. On the other hand, the brightness of the sky around the Sun will practically not fall, and we will not be able to see Venus, which on October 25 will be located about a degree from the solar disk. It is better not to try to do this, because for this you need to direct a telescope with unprotected optics towards our luminary, and this is strictly prohibited, since it can lead to loss of vision by the observer and damage to the astronomical instrument. And in general, you can only look at the Sun with a “simple eye” in two cases — when it is completely obscured by the Moon and when it is very low above the horizon during sunrise or sunset (but even then you should not stop your gaze on it for more than a couple of seconds).

View of the Sun at the moment of the maximum eclipse phase on October 25 in Kharkiv, Odesa and Lviv (zenith above)

The table shows the circumstances of the eclipse of October 25, 2022 for the largest cities of the unoccupied part of Ukraine: the moments of the beginning of the Moon’s entry into the solar disk (1st contact), the maximum phase and the end of the eclipse (4th contact). Kyiv summer time.

City1st contactMax. phaseMax. value phase4th contact
Lviv12:18:03 p.m.01:29:00 p.m.0.5302:40:05 p.m.
Vinnytsia12:22:20 p.m.01:35:40 p.m.0.5802:48:23 p.m.
Kyiv12:22:44 p.m.01:36:45 p.m.0.6102:49:50 p.m.
Odesa12:27:30 p.m.01:42:06 p.m.0.5702:55:28 p.m.
Mykolaiv12:28:02 p.m.01:43:08 p.m.0.5902:56:47 p.m.
Kryvyi Rih12:28:20 p.m.01:43:50 p.m.0.6202:57:42 p.m.
Kharkiv12:28:46 p.m.01:44:40 p.m.0.6602:58:32 p.m.
Dnipro12:29:10 p.m.01:45:05 p.m.0.6402:59:02 p.m.
Zaporizhzhia12:30:10 p.m.01:46:15 p.m.0.6303:00:20 p.m.

In Kyiv, eclipse observations will be organized on the basis of the Main Astronomical Observatory. We hope the weather will allow us to see it: as already mentioned, it interrupts the “chain” of similar phenomena observed annually in the Ukrainian territories. The next time we will be able to notice the Moon against the background of the solar disk on March 29, 2025 — this will also be a partial blackout, the maximum phase of which will reach 0.936. In the north-west of Ukraine, it will be visible with a phase of just over 11%, and the Ukrainian capital will be on the border of the visibility zone.

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