Planets of the Month: May & June 2025

By Erich Karkoschka

Mercury is well visible during the second half of June, not far from Pollux in Gemini. It sets at 9 pm, but already appears before 8 pm in the bright twilight.

Jupiter is close to Elnath, the southern star of the Auriga hexagon. It is visible low in the west during dusk until June 8, when Jupiter passes a few arc-minutes south of the summer solstice point, the location of the sun at the summer solstice. It marks the peak declination of its 12-year track through the constellations.

Mars is high in the southwest during dusk and sets around midnight. On June 15 it is less than a degree north of Regulus, which has the same magnitude but is bluish against Mars’ orange color.

After midnight, there are a couple of hours with no planet in sight. Except if you have dark sky and good vision, you can see Vesta, minor planet no. 4 at magnitude 6, even 5.6 during the first week of May. It passes through eastern Virgo, just south of the celestial equator. In May, it moves sufficiently fast to be able to notice its motion from night to night by naked eye.  In June it slows down to become prograde again.

Venus rises at 2:40 am in early May and an hour earlier by late June. It is close to maximum magnitude in early May.  It moves from the first point of Aries (which is in Pisces) to close to the Pleiades by the end of June.  In a telescope it is a beautiful crescent in May going through half illuminated in early June.

Saturn rises before 4 am at the beginning of May, but already at midnight by the end of June.  Saturn’s rings are invisible since the Earth is south of the ring plane while the sun still illuminates the northern side.  On May 6, the sun crosses the ring plane to the south, and the rings become better and better illuminated.  Saturn is close to first point of Aries, also close to Venus at the beginning of May. In the vicinity is also Neptune, and Saturn and Neptune will be only one degree apart from each other for all June and well into the summer, a great opportunity to easily locate Neptune in binoculars and telescopes.

The Moon is an extremely thin crescent on the evening of May 27 and a thicker one on June 26.

Planets of the Month: April 2025

By Erich Karkoschka

Jupiter is close to Aldebaran and setting around 11 pm.

Mars is a little further east near Pollux. Around 8 pm, it transits 80 degrees high. Telescopes still show details on its surface, but at 8 arc-seconds diameter, one cannot expect too much.

After all planets are down, Venus rises around 4 am. It reaches maximum brightness during the second half of April at magnitude -4.8. It displays a magnificent thin, large crescent, but getting smaller and thicker during April.

Mercury and Saturn become visible around the 10th in the morning. They can be found 6 degrees below Venus, close to the horizon during dawn. At mid-month, they are only 2 degrees apart from each other. Mercury is left of Saturn and a little brighter. Mercury stops its retrograde motion right next to Saturn and then quickly accelerates away from Saturn.

Uranus is 6 degrees south of the Pleiades, but becomes too close to the sun later to be observable.

Minor planet No. 4 Vesta is at its brightest in May. It will be visible to the naked eye. During April it rises in Libra around 8 pm.

The Full Moon will be very close to Spica on the 12th. On the morning of the 25th, its crescent is near Venus and Saturn, not far from Mercury. Neptune is also right there, but not visible.