May begins with a strong meteor shower and ends with a close conjunction of Mercury and Venus. Sandwiched between these two events is a total eclipse of a supermoon.

Totally eclipsed Moon, October 8, 2014.

This month, Hydra, the water serpent, is well-positioned for viewing. While the largest of the 88 constellations, Hydra’s relatively unknown, its brightest star being only magnitude 2.0. See if you can identify it on a moonless evening, stretching over 100 degrees of sky, its head below Cancer, its body beneath Sextans, Crater, and Corvus, and its tail ending at the Libra border.

May Planets:

Mercury is visible in the evening twilight for much of the month. It reaches eastern elongation on May 17, meaning that it appears at its farthest point east of the Sun. On this evening, Mercury sets at the end of astronomical twilight. During the last week of May, the innermost planet makes a close pairing with Venus.

Venus begins the month low in the WNW just after the Sun sets. By the end of May, it catches up with and passes Mercury near the Taurus – Gemini border.

Mars continues to fade as it recedes from Earth. An evening object all month, Mars sets around 11:15pm MDT at month’s end, near the Gemini – Cancer border.

Saturn is still a morning object in May. It slowly brightens during the month as its distance to Earth decreases. By May 31st, Saturn rises shortly after midnight in the constellation Capricornus.

Jupiter follows Saturn into the sky each morning, also brightening as Earth approaches it. Now located in Aquarius, Jupiter’s the brightest object in the morning sky, excluding the Moon.

Jupiter (left, above center) and Saturn (2 o’clock from Jupiter) rising in the predawn sky in April.

May Spotlight:

On the morning of May 26th, a full supermoon will set in the WSW, just after being totally eclipsed by the Earth’s shadow. From the Santa Fe area, totality begins at 5:11am MDT, one hour and four minutes after dawn commences. Totality ends 25 minutes before sunrise. These aren’t optimal conditions for viewing the eclipse, but at least we’ll be able to see it as dawn grows in the east.

A total lunar eclipse occurs when the Earth is directly between the Sun and the Moon, as the Moon orbits the Earth. The first phase of a lunar eclipse is the penumbral phase, in which the Moon approaches the Earth’s shadow. In this phase, sunlight passes through the Earth’s atmosphere before reaching the Moon, causing a very slight dimming at the Moon’s leading (left) edge. The umbral phase of a lunar eclipse begins when the Moon enters the Earth’s shadow. Total eclipse occurs when the Moon is completely within the Earth’s shadow.

Here are details of the May 26, 2021 total eclipse of the moon, specific to the Santa Fe area:

Penumbral eclipse begins:    2:47am MDT

Umbral eclipse begins:          3:45am MDT

Astronomical dawn begins:  4:07am MDT

Totality begins:                       5:11am MDT

Maximum eclipse:                  5:18am MDT

Totality ends:                          5:26am MDT

Sunrise:                                    5:51am MDT

Moonset:                                 5:58am MDT

Note: The umbral and penumbral eclipse phases end after the Moon has set at our location.

The duration of totality is quite short in this eclipse because the Moon is passing just below the top of Earth’s round shadow.

During totality, the Moon is still visible as a reddish disk, despite being covered by the Earth’s shadow. This is because sunlight passing through the Earth’s atmosphere is filtered and refracted, some of which reaches the Moon’s surface. The shade of red in a totally eclipsed moon depends on conditions in the Earth’s atmosphere (e.g., temperature, water content, cloud cover, dust), making each eclipse somewhat unique.

On January 31, 2018, a totally eclipsed Moon was setting above the Jemez Mountains as dawn brightened the sky.

May Night Sky Events:

May 6-7: The Eta Aquarid meteor shower peaks on the night of May 6th and before dawn on the 7th. This shower can produce 60 meteors per hour during its peak. The waning crescent moon won’t interfere with viewing.

May 11: New moon.

May 17: Mercury is at its farthest point east of the Sun, making it easy to see in the WNW, in late twilight, between the horns of Taurus.

May 26: A full supermoon eclipse occurs before sunrise. Totality begins at 5:11am MDT, well after dawn has begun. The moon, near the head of Scorpius (the scorpion), will be low in the WSW. It will appear somewhat similar to the total eclipse of January 31, 2018, which also occurred during dawn.

May 25-31: For several evenings around May 27th, Venus and Mercury will be close to one another in the WNW twilight, not far from the Crab Nebula (magnitude 8.4) in Taurus. Watch these fast-moving planets as they change position from night to night.