In May, Russians will be able to see a rare Blue micromoon.

May 2026 is notable for two full moons: the first, which is called the Flower Moon, has already occurred on May 1. The second, the Blue Moon, will happen on the last day of spring. The peculiarity of this astronomical event is that the Moon will be at the furthest point of its orbit from the Earth, so it will be possible to see a rare micromoon. Read about what the Blue Moon is, at what time it will rise and what its special feature is in the Izvestia article.

What is a Blue Moon?

A blue moon is an astronomical phenomenon in which two full moons can be observed in one calendar month. It is believed that the name comes from the English idiom Once in a Blue Moon (literally "once in a Blue Moon"), which implies a very rare event. Such an expression does not mean that an event is impossible, but indicates its exclusivity.

The blue Moon occurs due to the fact that one lunar cycle — the period from new moon to full moon — lasts 29.5 days. 12 lunar months pass in less than a calendar year, in 354 days. As a result of this discrepancy, an "additional" full moon appears every 2.5–3 years.

The astronomical phenomenon has no direct connection with color, most often it looks like an ordinary full moon. However, sometimes you can observe an optical illusion: small particles of smoke or ash in the air scatter waves of red color, as a result, the Moon acquires a blue hue. It is customary to distinguish between seasonal and calendar Blue Moons. There are usually three full moons in winter, spring, summer and autumn. If there is a fourth full moon in one season, then it is called the seasonal Blue Moon. A calendar moon is considered to be the second full moon that occurs within one calendar month.

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The second full moon of May 2026 is the exact date and time

In 2026, the Blue Moon will rise on May 31 at 11:45 Moscow time. You can specify the dates of full moons and find out the correct time of their observation in a particular region using specialized services or online calendars.

Astronomy also uses the definition of a seasonal Blue Moon. In this case, full moons also occur irregularly, but they allow for more accurate accounting of the astronomical seasons associated with the solstices and equinoxes. In the coming years, it will be possible to see the seasonal Blue Moon on May 20, 2027 at 13:59 Moscow time, then on August 24, 2029 at 04:51 Moscow time and on August 21, 2032 at 04:46 Moscow time.

Calendar Blue Moons also have their own periodicity. After 2026, the next such phenomenon is expected on December 31, 2028 at 19:48 Moscow time. Then it will be repeated on September 30, 2031 at 21:58 Moscow time.

Why is the Blue Moon in May 2026 considered special?

The blue Moon in May 2026 is considered special due to the fact that it coincides with the micromoon. This phenomenon occurs when a full moon occurs near the apogee, the point of the Moon's orbit that is as far away from Earth as possible. At such moments, the satellite looks a little smaller and dimmer compared to a normal full moon. The difference in size can be up to 10-14%, but for an untrained observer it remains almost invisible without special devices or comparative photographs.

It is the combination of the Blue Moon and the micromoon that makes the astronomical event so rare. Such coincidences occur much less frequently than each of these phenomena individually. In addition, the May micromoon will be the smallest in 2026 — the Earth's satellite will look about 5.5% smaller and 10.5% dimmer than usual. During the next micromoon, on June 30, the moon will visually decrease by only 5%.

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How to observe the full moon correctly

In order to observe the Blue Moon, no special equipment is required, as it will be clearly visible in clear weather. The Earth's satellite will appear in the sky shortly after sunset, rising from the opposite side of the horizon. To see the full moon, you should determine the point where the Sun sets and turn around in the opposite direction. It is important that the horizon line remains open, as the satellite will be located low above it.

Those who want to notice the differences in size are advised to use telescopes or take photographs for later comparison with other full moons of the year. When using a telescope, it is advisable to use special filters that reduce the intensity of light and make observation more comfortable for vision.

The most successful time for observation is considered to be the moment when the moon appears above the horizon. During this period, it often acquires warm shades — from golden to reddish, which creates favorable conditions for photographing. In addition, it is preferable to choose open spaces for observations, as far away from urban areas as possible. This reduces the impact of artificial lighting, which can impair the visibility of celestial objects.