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Catch Comet Swan
4/9/2025

Comet SWAN (C/2025 F2) was discovered using the SWAN camera on SOHO by amateur astronomers in March 2025. Officially named on April 8, it is currently visible in the northeastern sky at dawn and will transition to the evening sky by late April. The comet has been brightening and is expected to peak at magnitude 3.6 by its perihelion on May 1, as it passes near the Pleiades cluster. Mid-northern latitude observers are best positioned to view the comet, which offers a rare opportunity for astronomers and skywatchers.

In 2017, a solar wind compressed Jupiter’s magnetosphere, heating its upper atmosphere to over 500°C – much hotter than its usual 350°C. This hot region spanned half the planet’s circumference, defying earlier theories that heating is confined to polar areas. Researchers found that solar bursts hit Jupiter 2–3 times monthly, impacting its atmospheric dynamics globally. These insights help improve space weather forecasting, offering valuable lessons for protecting Earth from solar storms.

Check the Events Calendar

All Times are in Universal Time (UT)

2025-04-19
Mercury at highest altitude in morning sky

2025-04-21
Mercury at greatest elongation west

2025-04-21 01:35
Last Quarter Moon

2025-04-22
Peak of the Lyrid meteor shower

2025-04-24
Mercury at dichotomy

2025-04-24
Venus at greatest brightness

2025-04-25 01:00
Venus 2º north of Moon

2025-04-27 19:31
New Moon lunation 1266

2025-04-29 07:00
Moon 0.5º north of Pleiades

2025-04-30 18:00
Jupiter 5º south of Moon

Explore our Galleries

Credit: Michael Mattiazzo
Equipment: Canon 6D DSLR and a Sigma 200mm f/2.8 lens
A stack of ten 30-sec shots of Comet C/2024 G3 (ATLAS) just a day or two after the complete disintegration of the comet's nucleus. Near-linear features, synchronic bands and striae, are visible within the dust tail.

Credit: Christophe Pellier
Equipment: 305mm SW Flextube f/5 with ASI462MM camera
Jupiter's NTrZ has been undergoig dramatic change to kick off 2025. Here is an excellent shot showing the two distrubtions (bright white) and their wake of dark material just above the NEB.

Credit: Paul G. Abel
Equipment: 305mm Newtonian in IL and W15, W21, and W47 filters
A marvelous sketch of Venus that documents the cusp anomaly (i.e., the effect whereby the terminator deviates from it's usual path at the poles and becomes much flatter). Also note the presence of both polar cusp caps.

Credit: Michael Teoh
Equipment: Lunt 152mm Solar telescope and QHY5III678M camera
While normally tethered to the Sun, in this sharp image we see a prominence being hurled from the eastern limb of our home star.

Credit: KC Pau
Equipment: 250mm f/6 Newtonian with QHYCCD 290M
A detailed capture of the craters Aristoteles and Eudoxus showing their terraced wall structure. This shot was taken from a balcony of a high rise apartment in Hong Kong, catching the Moon between high-rise skyscrapers!

Credit: Clyde Foster
Equipment: 355mm Celestron Edge HD with PlayerOne Mars camera
Only when Saturn is in its Equinox season can we catch its moons cutting in front of the planet. Here we see the uncommon presentation of its largest moon, Titan, casting its shadow upon the cloud tops below.

Learn about the ALPO

The Association of Lunar and Planetary Observers (ALPO) is an international organization devoted to study the Sun, Moon, planets, asteroids, meteors, and comets. Our goals are to stimulate, coordinate, and generally promote the study of these bodies using methods and instruments that are available within the communities of both amateur and professional astronomers.

The ALPO collects and analyzes observations of various Solar System bodies and associated phenomena and publishes detailed reports concerning these bodies in its quarterly publication the Journal ALPO, otherwise known as The Strolling Astronomer. Membership in the ALPO includes receiving our journal, and back issues can be found in our Publications section.

We welcome and provide services for all individuals interested in lunar and planetary astronomy. For the novice observer, the ALPO is a place to learn and to enhance observational techniques. For the advanced amateur astronomer, it is a place where one's work will count. For the professional astronomer, it is a resource where group studies or systematic observing patrols add to the advancement of astronomy. Further details about the ALPO can be found here.

There are a range of membership levels available starting with annual dues of only $22. See the footer below for links on how you can become a member today.

Join ALPO

The Association of Lunar and Planetary Observers (ALPO) is an international organization devoted to study of the Sun, Moon, planets, asteroids, meteors, and comets. Celebrating our 75th anniversary in 2022, our goals are to stimulate, coordinate, and promote the study of these bodies using methods and resources available to both amateur and professional astronomers.

The science of astronomy has never been more exciting or dynamic than it is today - for the novice observer, the ALPO is a place to learn and enhance one’s observational techniques. For the advanced amateur astronomer, it is a place where one's work will matter. And for the professional astronomer, it is a resource where group studies or systematic observing patrols add to the advancement of astronomy.

ALPO members range from enthusiastic individuals with the desire to pursue an initial interest in astronomy to advanced amateurs to professional astronomers deeply involved in lunar and planetary astronomy.

Becoming a member is easy, and we welcome you to join us as we explore and learn more about this vast universe we all call home. Simply select one of the options below to get started.

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Paying by Mail

Download and complete the ALPO Membership form following the instruction on the form