Astronomical Events May 2026: New Moon, Eta Aquariids and Planetary Conjunctions
May 2026 is an eventful month for skywatchers. The New Moon on 16 May opens an ideal dark-sky window for deep-sky observing and long-focal-length astrophotography, while in the first week the Eta Aquariids bring the meteors of Halley's Comet onto the stage. Rounding out the month, a series of conjunctions between the Moon and the main planets — Saturn, Mars, Venus and Jupiter — animates both the morning and evening sky.
May 2026 at a Glance
- 1 May: Full Moon
- 5–6 May: Eta Aquariids peak
- 13 May: Moon near Saturn (morning sky)
- 14 May: Moon near Mars (morning sky)
- 16 May: New Moon — best period for faint objects
- 19 May: Moon near Venus (evening sky)
- 20 May: Moon near Jupiter (evening sky)
- 23 May: Lunar chiaroscuro effects — X and V
- 31 May: second Full Moon of the month
Moon Phases and Observing Planning
The distribution of Moon phases makes the second half of May the most favourable period for deep-sky observing. After the New Moon on 16 May, the evening sky gradually darkens and the nights between 14 and 22 May offer the best window for galaxies, nebulae and globular clusters.
- 1 May: Full Moon
- 8 May: Last Quarter
- 16 May: New Moon
- 23 May: First Quarter
- 31 May: Full Moon
The month hosts two full moons — a situation that arises when the lunar cycle (approximately 29.5 days) fits twice into a 31-day month. From an observing perspective, the relevant reference point is the New Moon: plan your deep-sky sessions during the week centred on 16 May.
Eta Aquariids: Halley's Comet Meteor Shower
The Eta Aquariids are the most significant meteor shower of spring. Originating from debris left by Halley's Comet along its orbit, the particles enter Earth's atmosphere at around 65 km/s — among the highest entry speeds of any annual shower — producing bright, often persistent trains lasting several seconds.
The peak is expected on the night of 5–6 May. The theoretical zenithal hourly rate can reach 50 meteors/hour under ideal conditions, but from northern Europe and northern Italy conditions are structurally less favourable than from the Southern Hemisphere: the radiant in the constellation Aquarius remains low above the south-eastern horizon and reaches its maximum altitude shortly before dawn. Realistically expect 10–20 meteors/hour from mid-northern latitudes.
Lunar conditions 2026: the peak falls five days after the Full Moon of 1 May. The Moon will still be bright and above the horizon for much of the night, suppressing fainter meteors. The best observing window is the two hours before astronomical dawn, when the radiant is at its highest and the Moon is already low in the west.
For astrophotography: aim a wide-angle lens towards the south-east, use exposures of 20–25 seconds, ISO 3200–6400, aperture fully open. Run a continuous sequence with an intervalometer throughout the night and select frames containing meteors during post-processing. Moonlight will require careful histogram management: avoid highlight clipping and work the tones in post.
Moon–Planet Conjunctions: Morning Sky (13–14 May)
In the second week of the month, a sequence of close encounters animates the pre-dawn morning sky:
- 13 May: Moon (13% illuminated) near Saturn (mag +0.9) in the constellation Pisces. Observable with the naked eye or binoculars. Through a telescope, Saturn's rings are already well displayed: at the end of May the planet shows an apparent diameter of approximately 18.6″ with the rings progressively opening.
- 14 May: Moon (5% illuminated) near Mars (mag +1.3) in the constellation Pisces. The thin crescent alongside the Red Planet makes an appealing subject for landscape photography with a telephoto lens.
Saturn rises around 1 a.m. at the start of May and already before midnight by month's end, making morning planetary sessions progressively more convenient as summer approaches. This is a good period to begin video-stacking sessions on Saturn's rings with a dedicated planetary camera.
Moon–Planet Conjunctions: Evening Sky (19–20 May)
Just days after the New Moon, the thin crescent takes centre stage in two close conjunctions in the evening sky:
- 19 May: Moon (8% illuminated) near Venus (mag −3.9) in the constellation Taurus. The "evening star" is by far the brightest object in the western sky after sunset. The pairing is a classic subject for twilight landscape photography.
- 20 May: Moon (20% illuminated) near Jupiter (mag −1.9). Jupiter emerges progressively from the morning twilight during May and begins to be visible in the evening sky towards month's end. The conjunction on the 20th is observable with the naked eye and binoculars.
23 May — Lunar Chiaroscuro: the X and V Effects
On 23 May, around First Quarter, the lunar terminator produces two characteristic chiaroscuro phenomena known as the Lunar X (or Clair-Obscur X) and the Lunar V. These are optical effects created by grazing illumination on specific mountain ranges and crater rims along the terminator, visible only within a roughly 1–2 hour window.
They are highly regarded subjects in high-magnification lunar photography: use a long-focal-length telescope, a planetary camera or DSLR in video mode, and apply stacking to maximise surface detail.
Deep-Sky in May: Making the Most of the New Moon Window
The week centred on 16 May is the best of the month for low-surface-brightness objects. The spring constellations still dominate the evening sky, offering excellent astrophotography targets:
- M3 (Canes Venatici) — one of the richest globular clusters in the northern sky, already well placed in the evening.
- M51 (Whirlpool Galaxy, Canes Venatici) — interacting galaxy pair with a visible bridge; an ideal target for an apochromatic refractor and colour camera.
- M101 (Ursa Major) — face-on spiral galaxy with low surface brightness: requires dark skies and many hours of integration.
- Virgo Cluster — the region between Virgo and Coma Berenices offers dozens of galaxies within a single field of view.
- M5 (Serpens) — globular cluster rising rapidly in the evening sky, already optimally positioned.
The May New Moon window is ideal for accumulating integration time on M51 or M101, targeting multi-night sessions with a broadband filter or unfiltered under dark skies.
Common Mistakes to Avoid
- Planning deep-sky sessions without checking Moon rise and set times.
- Waiting until midnight for the Eta Aquariids: the best window is the two hours before dawn.
- Underestimating atmospheric extinction for low-horizon conjunctions.
- Not checking seeing and transparency before planetary imaging sessions on Saturn.
May 2026 offers a continuous sequence of events: from the meteor shower at the start of the month to the evening conjunctions, through to the deep-sky window at mid-month. Careful planning — with an up-to-date sky app and weather monitoring — is the decisive factor in turning every appointment into a successful observing session.
The right equipment and informed planning are the foundation for making the most of the May sky.