Astronomical Diary
Calendar of Astronomical Events MAY 2024
Date Event Time
01-31 Dark and Quiet Skies ---
04 Conjunction of Waning Crescent Moon and Saturn 06:32 a.m.
04 Close approach of Waning Crescent Moon and Saturn 07:10 a.m.
05 Close approach of Moon and Mars 10:16 a.m.
05 Conjunction of Moon and Mars 10:25 a.m.
05 η-Aquariid meteor shower (ZHR = 40) ---
06 Moon at Perigee (Distance = 363,242.054 km) 06:04 a.m.
06 Conjunction of Moon and Mercury 04:25 p.m.
08 η-Lyrid meteor shower (ZHR = 3) ---
10 Mercury at Greatest Elongation West 05:29 a.m.
11 Mercury at Highest Altitude in Morning Sky ---
15 Mercury at dichotomy 07:04 a.m.
18 Moon at Apogee (Distance = 404,574.964 km) 02:59 a.m.
31 Conjunction of Moon and Saturn 04:09 p.m.
31 Close approach of Moon and Saturn 04:26 p.m.
Moon Phases
Last Quarter
May 01 07:27 PM
New Moon
May 08 11:22 AM
First Quarter
May 15 07:48 PM
Full Moon
May 23 09:53 PM
Last Quarter
May 31 01:13 AM
Rise and Set Times of Planets
Date Mercury Venus Mars Jupiter Saturn
Rise Set Rise Set Rise Set Rise Set Rise Set
May 01 04:19 am 04:32 pm 05:05 am 05:33 pm 03:20 am 03:22 pm 06:24 am 07:07 pm 02:38 am 02:26 pm
May 11 04:06 am 04:24 pm 05:08 am 05:46 pm 03:06 am 03:14 pm 05:54 am 06:38 pm 02:01 am 01:50 pm
May 21 04:08 am 04:38 pm 05:14 am 06:00 pm 02:52 am 03:06 pm 05:24 am 06:09 pm 01:24 am 01:14 pm
May 31 04:26 am 05:09 pm 05:22 am 06:15 pm 02:37 am 02:58 pm 04:53 am 05:40 pm 00:47 am 12:37 pm

* = following day

Stars and Constellation

May is the perfect month to observe the marvelous constellations of Canes Venatici and Coma Berenices in the northern hemisphere while Centaurus, Corvus, Crux, Musca, and Virgo are in the southern sky. The prominent May constellations at 09:00 p.m. on 15 May 2024 are positioned directly overhead as shown in Figure 1. [1,2]
Figure1
Figure 1: The view of the night sky featuring the prominent May constellations at 09:00 p.m. on 15 May 2024 using the Stellarium software

The northern constellations Canes Venatici and Coma Berenices are easy to locate for they are just above the handle of the famous asterism, the Big Dipper. [1,2]
Figure2
Figure 2: The Northern Constellations

Canes Venatici, Latin for “hunting dogs”, is a small northern constellation that presents a wealth of captivating celestial objects. The most renowned of these is the Whirlpool Galaxy (M51) [Figure 2a], one of the most stunning face-on spiral galaxies observable from Earth. Other notable galaxies include the Sunflower Galaxy (M63), and the Whale Galaxy (NGC 4631) to name a few. Cor Caroli, the brightest star in Canes Venatici, serves as one of the vertices of a prominent asterism, the Great Diamond, also formed by Denebola in Leo, Spica in Virgo, and Arcturus in Bo¨otes [Figure 2b]. Canes Venatici also houses one of the reddest stars in the sky, the La Superba (Y Canum Venaticorum). [2,3]

Despite Coma Berenices’ minor size, it is still rich in deep-sky objects. The constellation hosts the Coma Cluster of galaxies, as well as the northern portion of the Virgo Cluster making it abundant in galaxies. The most famous one is the Black Eye Galaxy (M64) [Figure 2c], distinguished by a dark absorbing dust band in front of the galaxy's bright core. The constellation also contains the Coma Star Cluster, a dense open star cluster nearly 288 light-years from Earth. [2,3]
Fiure3
Figure 3: The Southern Constellations

The zodiacal constellation Virgo is the second largest constellation, next to Hydra. Its brightest star, Spica, is a component of the Great Diamond and serves as one of the vertices of the Spring Triangle [Figure 2b]. Virgo is most well-known for the Virgo Cluster, an immense galaxy containing about 2,000 galaxies. Several Messier objects belong to the Virgo Cluster, namely, M49, M58, M59, M60, M61, M84, M86, M87, M89, and M90. The Sombrero Galaxy (M104) [Figure 3a], an unbarred spiral galaxy that resembles a sombrero, is the only Messier object not included in the Virgo Cluster. [2]

Included in the best-known southern constellations are Centaurus and Crux. Centaurus is a gold mine for deep-sky objects, hosting the brightest globular cluster in the sky, Omega Centauri. It also contains the third brightest star in the sky, Alpha Centaurus, and the 11th brightest star, Beta Centauri. These two stars are known as the Southern Pointers as they point towards the smallest constellation, Crux. [2]

Crux is considered the best-known constellation in the southern sky. It is used for celestial navigation to the southern hemisphere. Crux contains two notable deep-sky objects: the Jewel Box or Kappa Crucis Cluster, one of the youngest known open clusters, and the Coalsack Nebula [Figure 3b]. Its four bright stars - Acrux (Alpha Crucis), Mimosa (Beta Crucis), Gacrux (Gamma Crucis), and Imai (Delta Crucis) - form an asterism known as the Southern Cross. [2]

Corvus is a small southern constellation with an outstanding presence in the sky. Its four brightest stars – Gienah (Gamma Corvi), Kraz (Beta Corvi), Algorab (Delta Corvi), and Minkar (Epsilon Corvi) – form a quadrilateral asterism known as the Sail or Spica’s Spanker. Impressive deep-sky objects can be seen in Corvus including the Antennae Galaxies (NGC 4038 and NGC 4039) [Figure 3c], a pair of interacting galaxies, and the Ringtail Galaxy (NGC 4027). [2]

Musca, being one of the smallest and lesser-known constellations, does not host any Messier object. However, it is home to one of the oldest globular clusters of the Milky Way, NGC 4372. [4]

Planetary Location

Mercury can be seen lying low in the eastern sky in the early days of May, but will eventually be visible before sunrise as it reaches an altitude of more than 10° above the horizon. Mars and Saturn are morning objects, rising on the eastern horizon at least two hours before sunrise, presenting their visibility for the entire month. On the other hand, Jupiter will be sitting very low on the western horizon making it challenging to view as it gets lost in the glare of the Sun. Moreover, Venus will not be visible due to its proximity to the Sun. [1,5,6]
Figure4
Figure 4: The view of the eastern sky showing the close pairing of the Waning Crescent Moon and Saturn (on the left) and the Moon and Mars (on the right) at 05:00 a.m. using Stellarium

On 04 May, the Waning Crescent Moon and Saturn will be in conjunction at 06:32 a.m., with the Moon passing 50’ south of Saturn. The two objects will make a close approach, at about the same time, passing within 44.7 arcminutes of each other, where both planets lie in the constellation Aquarius. The next day, at 10:16 a.m., the Moon and Mars, located in the constellation Pisces, will pass within 10.3 arcminutes of each other, followed by their conjunction at 10:25 a.m., separated by 12’. The exact events will not be observable due to the presence of the Sun, however, the pairings can be seen close to each other at 05:00 a.m. when they will be more than 20° above the eastern horizon [Figure 4]. [7,8,9,10]

The Waning Crescent Moon and Mercury will share the same right ascension on 06 May at 04:25 p.m., with Mercury passing 3°49’ south of the Moon. Due to the time of these events, the conjunction will not be viewed by the naked eye because of the Sun’s presence, but the best view of their close pairing will be at 05:00 a.m. [Figure 5]. [11]
Figure5
Figure 5: The view of the eastern sky showing the close approach of the Waning Crescent Moon and Mercury on 06 May at 05:00 a.m. using Stellarium.
Figure6
Figure 6: The view of the east-southeastern sky showing the close approach of the Moon and Saturn on 31 May at 04:30 a.m. using Stellarium.

On 08 May, the Moon and Venus will be in conjunction at 12:03 a.m., with the Moon passing 3°30’ north of Venus. On the other hand, the Moon and Jupiter will share the same right ascension on 09 May at 02:14 a.m., separated by 4°19’ from each other. Unfortunately, the exact instances of these conjunctions are not directly visible since the Moon and the above-mentioned planets are still below the horizon. [5]

On 10 May at 05:29 a.m., Mercury will reach its Greatest Elongation West, when it will be farthest from the Sun by 26.4°. Mercury will shine with a magnitude of 0.4 and will be at its highest point in the morning sky the next day. On 15 May at 07:04 a.m., Mercury will undergo dichotomy, when the planet appears half-illuminated as seen from Earth. The exact time of the event will not be visible as it will occur below the horizon. [12,13,14]

Another conjunction of the Moon and Saturn will happen on the last day of the month, at 04:09 p.m., with the Moon passing 22’ south of Saturn. The two objects will approach closely at about the same moment, passing within 20.2 arcminutes of each other. Both planets will be behind the stars of the constellation Aquarius. Due to the presence of the Sun, the conjunction will not be viewed by the naked eye, but the best view of their close pairing will be at 04:30 a.m. when the two objects will be lying high in the east-southeastern sky [Figure 6]. [15,16]

All the conjunctions and near approaches mentioned between the planet and the Moon, or planet to planet, 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.

Meteor Shower

The η-Aquariid meteor shower will be observed from 19 April to 28 May with its peak activity on 05 May. The meteor shower is expected to produce about 40 meteors per hour. It will be visible once its radiant point, the constellation Aquarius, is above the eastern horizon around 01:33 a.m. each night and remains active until around 05:06 a.m. the next day. The radiant point is highest in the sky around 08:00 a.m. and will likely produce its best display shortly before dawn as seen in Figure 7. However, the presence of the Waning Crescent Moon will provide minimal impact on the meteor-watching throughout the night. [17]
Figure7
Figure 7: The view of the southeastern sky during the peak of η-Aquariid on 05 May 2024 at 08:00 a.m. when the shower’s radiant is represented by the green solid circle.
Figure8
Figure 8: The view of the northern sky during the peak of η- Lyrid on 08 May 2024 at 04:00 a.m. when the shower’s radiant is represented by the green solid circle.

Another meteor shower that can be viewed in May is the η-Lyrid meteor shower which will be active from 03-14 May, peaking on 08 May. In Manila, the shower will be observed around 08:57 p.m., when its radiant point, the constellation Lyra, rises above the eastern horizon until dawn breaks around 05:05 a.m. the following day. An estimate of 3 meteors per hour will be produced at the shower’s peak activity. The radiant point is highest in the sky around 04:00 a.m. providing the best view of the meteor as depicted in Figure 8. The moonlight will present an insignificant interference on the meteor observation. [18]

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 May 2024

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/ may-constellations, Last accessed on 2024-04-08, 2024.
[3] Go Astronomy, “Coma Berenices Constellation” https://www.go-astronomy.com/constellations.php?Name=Coma%20Berenices, Last accessed on 2024-04-08, 2024.
[4] Go Astronomy, “Musca Constellation” https://www.go-astronomy.com/constellations.php?Name=Musca, Last accessed on 2024-04-08, 2024.
[5] Multi-Interactive Computer Almanac (MICA), Last accessed on 2024-03-08, 2024.
[6] D. Ford, “In-The-Sky.org Guide to the night sky: “Objects in your sky: Planets” https://in-the-sky.org/data/planets.php/, Last accessed on 2024-04-08, 2024.
[7] 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=20240503_20_100, Last accessed on 2024-04-08, 2024.
[8] 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=20240503_15_100, Last accessed on 2024-04-08, 2024.
[9] D. Ford, “In-The-Sky.org Guide to the night sky: “Close approach of the Moon and Mars” https://in-the-sky.org/news.php? id=20240505_15_100, Last accessed on 2024-04-08, 2024.
[10] D. Ford, “In-The-Sky.org Guide to the night sky: “Conjunction of the Moon and Mars” https://in-the-sky.org/news.php? id=20240505_20_100, Last accessed on 2024-04-08, 2024.
[11] D. Ford, “In-The-Sky.org Guide to the night sky: “Conjunction of the Moon and Mercury” https://in-the-sky.org/news. php?id=20240506_20_100, Last accessed on 2024-04-08, 2024.
[12] D. Ford, “In-The-Sky.org Guide to the night sky: “Mercury at greatest elongation west” https://in-the-sky.org/news.php? id=20240509_11_101, Last accessed on 2024-04-08, 2024.
[13] 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=20240509_11_100, Last accessed on 2024-04-08, 2024.
[14] D. Ford, “In-The-Sky.org Guide to the night sky: “Mercury at dichotomy” https://in-the-sky.org/news.php?id=20240514_ 11_100, Last accessed on 2024-04-08, 2024.
[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=20240531_20_101, Last accessed on 2024-04-08, 2024.
[16] 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=20240531_15_100, Last accessed on 2024-04-08, 2024.
[17] D. Ford, “In-The-Sky.org Guide to the night sky: “η-Aquariid meteor shower 2024” https://in-the-sky.org/news.php?id= 20240505_10_100, Last accessed on 2024-04-08, 2024.
[18] D. Ford, “In-The-Sky.org Guide to the night sky: “η-Lyrid meteor shower 2024” https://in-the-sky.org/news.php?id= 20240508_10_100, Last accessed on 2024-04-08, 2024.


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 add: astronomy@pagasa.dost.gov.ph