PAGASA

Calendar of Astronomical Events DECEMBER 2025

Date	Event	Time
02	Comet C/2025 T1 (ATLAS) passes perihelion	---
02	Phoenicid meteor shower (ZHR = var)	---
04	Mercury at dichotomy	04:05 p.m.
04	Moon at Perigee (Distance = 357,073.343 km)	07:07 p.m.
06	December φ-Cassiopeid meteor shower (ZHR = 2)	---
07	Mercury at highest altitude in morning sky	---
07	Puppid-Velid meteor shower (ZHR = 10)	---
07	Conjunction of the Waning Gibbous Moon and Jupiter	11:47 p.m.
08	Close approach of the Waning Gibbous Moon and Jupiter	01:10 a.m.
08	Mercury at greatest elongation west	05:03 a.m.
08	Monocerotid meteor shower (ZHR = 2)	---
11	σ-Hydrid meteor shower (ZHR = 3)	---
12	λ-Sculptorid 2025 meteor shower (ZHR = var)	---
14	Geminid meteor shower (ZHR = 120)	---
17	Moon at Apogee (Distance = 406,277.011 km)	02:09 p.m.
20	December Leonis Minorid meteor shower (ZHR = 5)	---
21	December Solstice	11:03 p.m.
22	Ursid meteor shower (ZHR = var)	---
27	Conjunction of the Moon and Saturn	11:34 p.m.

Moon Phases

	Full Moon
	Dec 05	07:14 AM
	Last Quarter
	Dec 12	04:52 AM
	New Moon
	Dec 20	09:43 AM
	First Quarter
	Dec 28	03:10 AM

Rise and Set Times of Planets

Date	Mercury		Venus		Mars		Jupiter		Saturn
Date	Rise	Set	Rise	Set	Rise	Set	Rise	Set	Rise	Set
Dec 01	04:47 am	04:17 pm	05:27 am	04:50 pm	06:53 am	06:05 pm	08:33 pm	09:27 am*	01:03 pm	01:01 am*
Dec 11	04:41 am	04:08 pm	05:43 am	05:01 pm	06:46 am	05:57 pm	07:51 pm	08:45 am*	12:24 pm	12:22 am*
Dec 21	05:01 am	04:20 pm	06:00 am	05:14 pm	06:40 am	05:51 pm	07:07 pm	08:01 am*	11:45 am	11:40 pm
Dec 31	05:28 am	04:42 pm	06:16 am	05:29 pm	06:33 am	05:46 pm	06:22 pm	07:17 am*	11:08 am	11:03 pm

* = following day

Stars and Constellation

As the year draws to a close, the December night sky offers stargazers a splendid display of both northern and southern constellations that have inspired stories, myths, and scientific curiosity through the ages. The long, cool nights of this month provide ideal viewing conditions, as darkness arrives early and lingers well into the morning hours. The northern hemisphere is adorned with the graceful constellations of Perseus, Aries, and Triangulum, while the southern skies unveil the faint yet fascinating patterns of Eridanus, Fornax, and Horologium. These constellations will appear directly overhead at 09:00 p.m. on 15 December 2025, as illustrated in Figure 1. [1]

Figure 1: The view of the night sky featuring the prominent December constellations at 09:00 p.m. on 15 December 2025 using the Stellarium software.

Triangulum, the Triangle, is a modest and faint constellation, with none of its stars shining brighter than magnitude 3.00. Nevertheless, its distinct three-star pattern and abundance of celestial objects make it a fascinating region for both amateur and professional astronomers to explore. Its three brightest stars, which outline the constellation’s distinctive triangular shape, are Deltotum (Beta Trianguli) with a magnitude of 3.00, Mothallah (Alpha Trianguli) with a magnitude of 3.42, and Gamma Trianguli with a magnitude of 4.03. Though lacking in stellar brilliance, the constellation encompasses several interesting deep-sky objects, the most notable being the Triangulum Galaxy (M33) [Figure 2a]. Located about 3 million light-years away, this spiral galaxy is the third-largest member of the Local Group after the Milky Way and Andromeda, and is one of the most distant objects visible to the naked eye under dark skies. Located in the Triangulum Galaxy, NGC 604 [Figure 2b] is one of the largest known H II regions and a significant site for examining star formation and stellar evolution. The constellation also contains several other galaxies, including the spiral galaxies NGC 634, NGC 784, and NGC 925. [2,3]

Aries, the Ram, may not be among the most visually striking constellations, but it occupies a notable position along the ecliptic as one of the twelve zodiac constellations. It once marked the position of the vernal equinox, but due to the gradual precession of Earth’s axis, this point has since shifted into Pisces. Aries contains only two stars brighter than magnitude 3.00. Hamal (Alpha Arietis), its brightest, is an orange giant about 66 lightyears away with a magnitude of 2.00—roughly as bright as Polaris, the North Star. Sheratan (Beta Arietis), a spectroscopic binary with a magnitude of 2.65, has a white main-sequence star as its primary component. Beyond its stars, Aries also contains several notable galaxies, including the spiral NGC 772 and its companion NGC 770. NGC 772 [Figure 2c] is known for its extended, asymmetric arms formed through gravitational interaction with its neighbor. Aries also features the interacting galaxies NGC 935 and IC 1801, along with the spiral galaxy NGC 877. [2,4,5]

Figure 2: The Northern Constellations

Fornax, the Furnace, is a faint southern constellation introduced by French astronomer Nicolas-Louis de Lacaille. Named after the furnace used in chemical experiments during Lacaille’s time, it is home to the yellow giant star Dalim (Alpha Fornacis). Located about 46 light-years away, Dalim is 34 times more luminous than the Sun, with an apparent magnitude of 3.85. Although it lacks bright stars, Fornax holds significant interest for astronomers due to its abundance of distant galaxies and its association with the Fornax Cluster—a rich collection of galaxies located about 62 million light-years away. The cluster contains nearly 60 galaxies, including the barred spiral galaxy NGC 1365 [Figure 3a], known as the Great Barred Spiral Galaxy, and the lenticular galaxy NGC 1316 (Fornax A) [Figure 3b]. NGC 1365 is one of the most prominent barred spirals, while Fornax A is the fourth brightest radio source in the sky, featuring an intricate system of dark dust lanes. [6]

Another constellation presented by Nicolas-Louis de Lacaille is Horologium, the Clock, the southernmost December constellation, originally named ”Horologium Oscillatorium” to honor the pendulum clock, a key invention of his era. It is a faint constellation, with its brightest star, Alpha Horologii, a distant orange giant located 115 light-years away, shining at an apparent magnitude of 3.85. Horologium may not feature bright stars, but it is a noteworthy area in the sky, primarily recognized for its fascinating deep-sky attractions, particularly the Horologium-Reticulum Supercluster, a massive galaxy cluster 700 million light-years away. It also hosts the Horologium Dwarf, a galaxy in the Local Group, and other intriguing objects like NGC 1261, a globular cluster, and NGC 1433 [Figure 3c], a Seyfert galaxy with an exceptionally bright, active nucleus. [7]

Figure 3: The Southern Constellations

Planetary Location

This December, Saturn appears high above the horizon as twilight fades, gracing the night sky until it finally sets in the west. Visible from early evening until sunrise, Jupiter shines brilliantly before being obscured by the Sun’s glare. Mercury offers a brief glimpse, sitting low in the east-southeastern horizon at dawn from early to mid-month, before fading from view as it draws closer to the Sun. The smallest planet will reach its half-illuminated phase, known as dichotomy, on 04 December at 04:05 p.m. It will shine brightly at magnitude –0.5 as it attains its highest altitude in the morning sky on 07 December, and will reach its greatest elongation from the Sun the following day at 05:03 a.m. Unfortunately, Venus and Mars will not be observable this month, as both are positioned too close to the Sun. [1,8,9,10,11]

On 07 December, at 11:47 p.m., the Waning Gibbous Moon, radiating at magnitude -12.7, will share the same right ascension with Jupiter, shining at magnitude -2.6, as they appear just 3°42’ apart in the sky. By 01:10 a.m. the following day, the two luminous bodies will move even closer, narrowing their separation to 3°36’, set beautifully against the stellar background of Gemini. The exact timing of these celestial events is depicted in Figure 4, offering a visual guide to their appearance in the night sky. [12,13]

Figure 4: The view of the eastern sky showing the a) conjunction and b) close approach of the Moon and Jupiter using Stellarium.

On 27 December at 08:08 a.m., the 7-day-old Moon and Saturn will make a close approach, appearing just 3°32’ apart in the night sky. Later, at 11:34 a.m., the Moon and Saturn will reach conjunction, with the Moon passing 4°01’ north of Saturn. At
that time, the Moon will shine brilliantly at magnitude -11.8, set against the background stars of Pisces, while Saturn, located within the boundaries of Aquarius, glows modestly at magnitude 0.9. Although their close approach occurs while both objects are
still below the horizon and their conjunction is obscured by the Sun’s glare, the pair will become visible for observers starting at 06:20 p.m. on 27 December over the southwestern sky, remaining in view until they set in the western sky [Figure 5]. [14,15]

Figure 5: The view of the southwestern sky showing the close pairing of the Moon and Saturn on 27 December at 06:20 p.m. using Stellarium.

All the conjunctions and near approaches mentioned between the planet and the moon, or between planets, will be visible enough to fit within the field of view of a telescope and can also be viewed with the naked eye or using a pair of binoculars.

December Solstice

The December Solstice will occur on 21 December at 11:03 p.m., marking one of the most significant astronomical events of the year. On this day, the Sun reaches its southernmost point along the ecliptic, positioned in the constellation Capricornus at a declination of 23.5°S. This celestial milestone signals the beginning of winter in the Northern Hemisphere, known as the Winter Solstice, when the longest night of the year occurs, and the start of summer in the Southern Hemisphere, the Summer Solstice, when daylight lasts longer than on any other day. [8,16]

Comet C/2025 T1 (ATLAS)

Comet C/2025 T1 (ATLAS) will make its closest approach to the Sun on 02 December, reaching a perihelion distance of 1.11 AU in the Vulpecula constellation. While its estimated visual magnitude of 10.9 means it won’t be visible to the naked eye from Manila, the comet will be observable through binoculars or a small telescope. For several weeks, from early December through the third week of the month, the comet will be visible in the western sky after sunset, moving from Vulpecula to Aquila. [17]

Meteor Shower

The Puppid-Velid meteor shower, though often overlooked, presents an intriguing display each year from 01-15 December, peaking on 07 December. Radiating from the constellation Vela, the shower typically produces about 10 meteors per hour under favorable conditions. The best viewing period spans from 10:01 p.m., when the radiant point rises above the eastern horizon, and continues until dawn at about 05:42 a.m., with the most favorable time occurring around 03:00 a.m. [Figure 6] when the radiant reaches its highest point in the sky. During this window, the Puppid-Velids are at their most visible, presenting a stunning display of meteors streaking across the night sky. This year, the near-full Moon in Gemini will cause significant interference, washing out the fainter meteors throughout the night. [18]

Figure 6: The view of the southern sky during the peak of the Puppid-Velid meteor shower on 07 December 2025 at 03:00 a.m., when the shower’s radiant is represented by the green solid circle.

The Geminid meteor shower, one of the year’s most anticipated celestial events, runs annually from 04-20 December, peaking on 14 December. Known for producing up to 120 meteors per hour under ideal conditions, the Geminids stand out due to their parent body, the asteroid 3200 Phaethon, rather than a comet. The best viewing time is after the shower’s radiant in Gemini rises around 07:11 p.m., with meteors visible until about 05:46 a.m. The peak occurs around 02:00 a.m. [Figure 7], when the radiant reaches its highest point, offering the most intense display. This year, the Geminids will peak near the new moon, ensuring minimal moonlight interference and optimal viewing conditions. With clear, dark skies, the Geminids promise a spectacular show for stargazers. [19,20]

Figure 7: The view of the northwestern sky during the peak of the Geminid meteor shower on 14 December 2025 at 02:00 a.m., when the shower’s radiant is represented by the green solid circle

December is home to the highest number of meteor showers in the year. Several minor showers are also active throughout the month, including the following:

Meteor Shower Name	Radiant	Active Date	Peak Date	Best Viewed Time	ZHR	Lunar Phase
Phoenicids	Phoenix	Nov 28-Dec 09	Dec 02	08:00 p.m.	var	Waxing Gibbous
December φ-Cassiopeids	Andromeda	Dec 01-08	Dec 06	08:00 p.m.	2	Waning Gibbous
Monocerotids	Monoceros	Dec 05-20	Dec 08	01:00 a.m.	2	Waning Gibbous
σ-Hydrids	Hydra	Dec 03-15	Dec 11	03:00 a.m.	3	Waning Crescent
λ-Sculptorids 2025	Leo	Dec 12-23	Dec 12	before dawn	var	Waning Crescent
Comae Berenicids	Leo	Dec 12-Feb 04	Dec 16	before dawn	3	Waning Crescent
December Leonis Minorids	Leo Minor	Dec 05-24	Dec 20	05:00 a.m.	5	Waxing Crescent
Ursids	Ursa Minor	Dec 17-26	Dec 22	before dawn	var	Waxing Crescent

Meteor showers are observable through the naked eye, and no special equipment such as telescopes or binoculars is needed. Maximize the viewing experience by choosing a dark observation site away from the city lights under clear and moonless sky conditions.

Watch: Astronomical Events for December 2025

Notes and References

Notes:
*following day
• All times displayed are in Philippine Standard Time (PhST)

References:
[1] PAGASA Special Publication No. 840; The Philippine Star Atlas 2019/Stellarium Software
[2] C. Guide, “Constellations: A Guide to the Night Sky.” https://www.constellation-guide.com/constellations-by-month/december-constellations/, Last accessed on 2025-11-11, 2025.
[3] Go Astronomy, “TRIANGULUM CONSTELLATION” https://www.go-astronomy.com/constellations.php?Name=Triangulum, Last accessed on 2025-11-11, 2025.
[4] Go Astronomy, “ARIES CONSTELLATION” https://www.go-astronomy.com/constellations.php?Name=Aries, Last accessed on 2025-11-11, 2025.
[5] The Constellation Directory, “Aries” http://www.constellationdirectory.org/constellations/aries.html, Last accessed on 2025-11-11, 2025.
[6] Go Astronomy, “FORNAX CONSTELLATION” https://www.go-astronomy.com/constellations.php?Name=Fornax, Last accessed on 2025-11-11, 2025.
[7] Go Astronomy, “HOROLOGIUM CONSTELLATION” https://www.go-astronomy.com/constellations.php?Name=Horologium, Last accessed on 2025-11-11, 2025.
[8] Multi-Interactive Computer Almanac (MICA), Last accessed on 2025-11-11, 2025.
[9] D. Ford, In-The-Sky.org Guide to the night sky: “Mercury at dichotomy” https://in-the-sky.org/news.php?id=20251204_11_100, Last accessed on 2025-11-11, 2025.
[10] D. Ford, In-The-Sky.org Guide to the night sky: “Mercury at highest altitude in morning sky” https://in-the-sky.org/news.php?id=20251208_11_100, Last accessed on 2025-11-11, 2025.
[11] D. Ford, In-The-Sky.org Guide to the night sky: “Mercury at greatest elongation west” https://in-the-sky.org/news.php?id=20251208_11_101, Last accessed on 2025-11-11, 2025.
[12] D. Ford, In-The-Sky.org Guide to the night sky: “Conjunction of the Moon and Jupiter” https://in-the-sky.org/news.php?id=20251207_20_100, Last accessed on 2025-11-11, 2025.
[13] D. Ford, In-The-Sky.org Guide to the night sky: “Close approach of the Moon and Jupiter” https://in-the-sky.org/news.php?id=20251207_15_100, Last accessed on 2025-11-11, 2025.
[14] D. Ford, In-The-Sky.org Guide to the night sky: “Close approach of the Moon and Saturn” https://in-the-sky.org/news.php?id=20251227_15_100, Last accessed on 2025-11-11, 2025.
[15] D. Ford, In-The-Sky.org Guide to the night sky: “Conjunction of the Moon and Saturn” https://in-the-sky.org/news.php?id=20251227_20_100, Last accessed on 2025-11-11, 2025.
[16] D. Ford, In-The-Sky.org Guide to the night sky: “December solstice” https://in-the-sky.org/news.php?id=20251221_07_100, Last accessed on 2025-11-11, 2025.
[17] D. Ford, In-The-Sky.org Guide to the night sky: “Comet C/2025 T1 (ATLAS) passes perihelion” https://in-the-sky.org/news.php?id=2025_19_CK25T010_100, Last accessed on 2025-11-11, 2025.
[18] D. Ford, In-The-Sky.org Guide to the night sky: “Puppid-Velid meteor shower 2025” https://in-the-sky.org/news.php?id=20251207_10_100, Last accessed on 2025-11-11, 2025.
[19] D. Ford, In-The-Sky.org Guide to the night sky: “Geminid meteor shower 2025” https://in-the-sky.org/news.php?id=20251214_10_100, Last accessed on 2025-11-11, 2025.
[20] IMO – International Meteor Organization, “List of Meteor Showers for Observation Session” https://www.imo.net/members/imo_showers/working_shower_list, Last accessed on 2025-11-11, 2025.
[21] D. Ford, In-The-Sky.org Guide to the night sky: “Meteor Showers” https://in-the-sky.org//newsindex.php?feed=meteors,Last accessed on 2025-11-11, 2025.

For more information, call or email:

Ms. Ma. Rosario C. Ramos
Chief, SSAS - RDTD
PAGASA - DOST
Diliman, Quezon City
Trunkline: 8284-0800 loc 3015, 3016, 3017
Email address: astronomy@pagasa.dost.gov.ph

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