ISO week 21 2025

This week is currently in preparation and will be published as part of the Star Almanack.

Week begins: Monday, May 19, 2025

Notation:

Calendar

Date	Zodiac day	Events
Mon, May 19, 2025	31	Coma Berenices center — Constellation — V 4.3 — Tropical Spring M60, elliptical galaxy in Virgo — V 8.8 — Tropical Spring C98, NGC 4609, open cluster in Crux — V 6.9 — Southern Spring NGC 4656, Hockey Stick or Crowbar, galaxy in Canes Venatici — V 9.7 — Finest NGC — Northern Spring
Tue, May 20, 2025	1	Sun enters Gemini — 18:54:38 UTC 🌗 Last Quarter — 11:58:46 UTC Mimosa (β Cru) — V 1 — Southern Spring β Mus — V 3 — Antarctic Spring C52, NGC 4697, elliptical galaxy in Virgo — V 9.3 — Tropical Spring NGC 4699, galaxy in Virgo — V 10.4 — Finest NGC — Tropical Spring
Wed, May 21, 2025	2	Alioth (ε UMa) — V 2 — Northern Spring M94, spiral galaxy in Canes Venatici — V 8.2 — Northern Spring C94, NGC 4755, Jewel Box Cluster, open cluster in Crux — V 4.2 — Southern Spring C99, Coalsack, Coalsack Nebula, dark nebula in Crux — Southern Spring NGC 4725, galaxy in Coma Berenices — V 9.9 — Finest NGC — Northern Spring NGC 4762, galaxy in Virgo — V 11.1 — Finest NGC — Tropical Spring
Thu, May 22, 2025	3	α1 CVn — V 6 — Northern Spring Cor Caroli (α2 CVn) — V 3 — Northern Spring M64, Black Eye Galaxy, spiral galaxy in Coma Berenices — V 8.5 — Tropical Spring
Fri, May 23, 2025	4	C35, NGC 4889, elliptical galaxy in Coma Berenices — V 11.4 — Northern Spring C105, NGC 4833, globular cluster in Musca — V 7.3 — Antarctic Spring
Sat, May 24, 2025	5	Centaurus center — Constellation — V 3.4 — Southern Spring Great Diamond center — Asterism — V -0.1 — Tropical Spring C83, NGC 4945, barred spiral galaxy in Centaurus — V 9.5 — Southern Spring
Sun, May 25, 2025	6	Diadem (α Com) — V 4 — Tropical Spring α Com — V 5 — Tropical Spring Canes Venatici center — Constellation — V 3.6 — Northern Spring Spring Triangle center — Asterism — V -0.1 — Tropical Spring

Weekly Solar-System Ephemeris

Snapshot: May 19, 2025 · 00:00 UTC

Notation:

Naked Eye

☉︎ Sun	☽︎ Moon	☿︎ Mercury	♀︎ Venus	♂︎ Mars	♃︎ Jupiter	♄︎ Saturn
♉︎ 28°17′ β −0°00′	♒︎ 9°56′ β −3°36′	♉︎ 15°28′ β −1°20′	♈︎ 13°07′ β −1°12′	♌︎ 14°18′ β +1°40′	♊︎ 25°08′ β −0°12′	♓︎ 29°31′ β −2°03′
Observing
☉		☉

Extended targets:

⚳︎ Ceres	♅︎ Uranus	♆︎ Neptune	♇︎ Pluto
♈︎ 0°43′ β −9°14′	♉︎ 27°21′ β −0°13′	♈︎ 1°36′ β −1°17′	♒︎ 3°46′ β −3°36′
Observing
	☉

β = ecliptic latitude (+ north, − south). Observing combines visual magnitude with solar elongation. Two telescope glyphs = substantial telescope. ☉ = Near Sun — not currently observable.

Notation:

Planet Finder

Planet Finder — Mixed Learner — Mixed Learner

Sky Notes

Naked eye

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Binoculars

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Telescope

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