ISO week 17 2025

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

Week begins: Monday, April 21, 2025

Notation:

Calendar

Date	Zodiac day	Events
Mon, Apr 21, 2025	3	🌗 Last Quarter — 01:35:34 UTC
Tue, Apr 22, 2025	4	Lyrids peak · radiant in Lyra · expected ZHR ≈ 18 · Moon 38% illuminated: moderate moonlight interference · Use a dark site, allow 20–30 minutes for dark adaptation, and observe with the unaided eye. Watch a broad area of sky rather than staring directly at the radiant. Alkes (α Crt) — V 4 — Tropical Spring
Wed, Apr 23, 2025	5	Dubhe (α UMa) — V 2 — Northern Spring Merak (β UMa) — V 2 — Northern Spring Ursa Major center — Constellation — V 3.2 — Northern Spring
Thu, Apr 24, 2025	6	C91, NGC 3532, open cluster in Carina — V 3.0 — Southern Spring NGC 3521, galaxy in Leo — V 9.9 — Finest NGC — Tropical Spring
Fri, Apr 25, 2025	7	β Crt — V 4 — Tropical Spring M97, Owl Nebula, planetary nebula in Ursa Major — V 9.9 — Northern Spring M108, spiral galaxy in Ursa Major — V 10.0 — Northern Spring
Sat, Apr 26, 2025	8
Sun, Apr 27, 2025	9	🌑 New Moon — 19:31:09 UTC M65, spiral galaxy in Leo — V 9.3 — Tropical Spring M66, spiral galaxy in Leo — V 8.9 — Tropical Spring C40, NGC 3626, spiral galaxy in Leo — V 10.9 — Tropical Spring NGC 3607, galaxy in Leo — V 10.9 — Finest NGC — Tropical Spring NGC 3628, galaxy in Leo — V 10 — Finest NGC — Tropical Spring

Weekly Solar-System Ephemeris

Snapshot: April 21, 2025 · 00:00 UTC

Notation:

Naked Eye

☉︎ Sun	☽︎ Moon	☿︎ Mercury	♀︎ Venus	♂︎ Mars	♃︎ Jupiter	♄︎ Saturn
♉︎ 1°09′ β −0°00′	♒︎ 0°21′ β −4°21′	♈︎ 3°52′ β −2°25′	♓︎ 25°49′ β +2°56′	♌︎ 1°11′ β +2°12′	♊︎ 19°26′ β −0°16′	♓︎ 26°48′ β −1°59′
Observing
☉

Extended targets:

⚳︎ Ceres	♅︎ Uranus	♆︎ Neptune	♇︎ Pluto
♓︎ 21°14′ β −8°24′	♉︎ 25°46′ β −0°13′	♈︎ 0°46′ β −1°16′	♒︎ 3°46′ β −3°31′
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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