Due to the increasing length of the day, the useful observation times will be reduced from five hours at the beginning of May to just two hours at the end of the month. This would mean that the start of observations of galaxies and similar faint objects would shift from 23:00 CEST to 0:30 CEST. For this reason the observatory is only open from the beginning of May to the end of August under certain conditions. These include, for example Observation of the sun and moon on some weekends. The times will be announced via a ticker on our main page.

SUN AND MOON

In the spring month of May, the day length for Zweibrücken increases from 14 hours and 46 minutes at the beginning to 16 hours and 4 minutes at the end of the month. The maximum height of the sun on May 31 is already an impressive 62 degrees.
The full moon on May 23 will affect the observation of fainter objects.

On May 5 at around 5:00 a.m., the narrow crescent of the waning moon will pass just under one degree north of Mars. However, a small telescope is needed to observe it. The occultation of Mars remains hidden from us; it only takes place in a strip from Madagascar, Indonesia, south-east Asia to Japan.

PLANETS

May, like April, is poor in planets.

Mercury reaches its greatest western angular distance from the Sun on the 9th of the month at 29.3 degrees, but this is not sufficient for morning visibility, as the ecliptic is very flat in the morning sky.

Venus is approaching its upper conjunction with the Sun. Upper conjunction means that the Earth, Sun and the object, in this case Venus, are aligned. The term upper and lower conjunction is only used for Mercury and Venus.

Mars appears low in the morning sky in the last third of May. Due to its distance and the associated optical size, it remains uninteresting as an object for telescope observers.

On the 18th of the month Jupiteras seen from Earth, opposite the Sun (conjunction). It therefore remains unobservable.

Saturn continues to behave hesitantly, on the first of the month it crosses the horizon in Zweibrücken at 4:31 am, on the last of the month it rises at 2:38 am.

Uranus and Neptune are still not observed.

STARRY SKY

Direction West the twins are already in the process of setting. Cancer is already stuck in the haze layers near the horizon. Leo is still a little higher up.
In Greek mythology, the lion is often associated with the hero Hercules (Heracles). According to one source, it is said to be the Nemean Lion, who was up to mischief near the city of Nemea and harassed the inhabitants there. The first of Hercules' twelve tasks was to defeat the lion. However, every weapon bounced off his fur, so the Greek hero had to face the lion with his bare hands in order to defeat him. From then on, the skin protected Hercules from his enemies. At Hera's request, Zeus moved the lion to heaven.

About us are the hair of Berenice with a multitude of galaxies, although a medium-sized telescope is required to observe them. A little further to the east is the Bear Keeper with its bright main star, Arcturus. A little trick makes it easier to find. If you extend the three drawbar stars of the "Big Dipper" in an arc, you will come across a bright star, Arcturus.
Here is a graphic for orientation:

Next Eastbound you come across the inconspicuous constellation Hercules with its bright globular cluster M13, which is already a magnificent sight in binoculars. In the image above on the left.

Just above the southeastern horizon the summer constellation of Scorpio appears towards the middle of the month. In the Northeastthe summer constellations enter the celestial stage.

Low on the northern night sky you can see the "celestial W", Cassiopeia, on the other side of the pole star as seen from the Great Bear.

Note: To the east of the Bear Keeper is the Northern Crown, in which a free-eyed observable nova should appear by September. An article about this can be found here. A nova is, briefly explained, a periodic phenomenon in which mass flows from a red giant star onto its companion, a white dwarf. When a critical mass is reached, a new short-lived nuclear fusion (thermonuclear explosion) starts, which ejects the mass into space. This process lasts a few days.

The following sky view is valid for May 1 at midnight, May 15 at 11 pm and May 30 at 10 pm.

Due to the later onset of twilight, the observatory opens on Friday evenings in April one hour later at 21:00, assuming a cloudless night sky.
Due to the irregular distribution of activity, this year's Maximum of the Lyrids on the morning of April 23 with a maximum of around 20 meteors per hour will be difficult to observe due to the almost full moon. According to Chinese records from 687 BC, "stars fell like rain" from the sky at that time. In 1982, up to 90 meteors per hour were recorded. The origin of the April Lyrids can be attributed to comet C/1861 G1 (Thatcher), which was discovered on April 4, 1861 by the British amateur astronomer A. E. Thatcher. Its orbital period is 416 years.

SUN AND MOON

On the first of the month, the central star rises in Zweibrücken at 7:04 am and sets at 8:05 pm. The length of the day is 13 hours 1 minute and increases further to 14 hours 43 minutes at the end of the month. The full moon on 24.04. will affect the view of fainter objects and thus also the Lyrids (see above).

On April 10 at 21:00, there will be an interesting view of the sky when the still young crescent moon appears to pay a visit to the large gas planet Jupiter just above the western horizon. At the time indicated above, the moon is approx. 3.3 degrees northwest of the planet.

PLANETS

Almost all the convertible stars retire from the night sky during the course of the month. However, replacements are already near the starting holes.

Mercury has retreated to the daytime sky and can therefore no longer be observed.

The morning star that has been visible in recent months Venus has also retreated to the daytime sky. Our sister planet will not be visible in the evening sky again until August.

Mars will not appear in the morning sky again until the last third of May, as described in the overview for March.

Jupiter is still apparently approaching the sun. For telescope observers, it is no longer of great interest due to its apparently decreasing diameter and increasing distance from Earth. At the time of opposition in November 2023, its distance was 3.98 astronomical units (595 billion km) with a diameter of 49.5 arc seconds. On April 15, 2024, the distance is 5.90 AU (883 billion km) with a diameter of only 33.4 arc seconds. It will no longer be visible to the naked eye from the end of April.

Saturn can gradually assert itself against the sun towards the end of the month, late in the morning sky.

Uranus and Neptune move in the daytime sky and are therefore invisible to us.

STARRY SKY

The spring constellations are now high in the sky. Only in the west are the remains of the winter constellations still visible. Above us you can see the spring triangle, which consists of the bright stars Arcturus in Ursa Major, Spica in Virgo and Regulus in Leo.

Deep in the South are the inconspicuous constellations of the Cup and the Raven and, to the south and west, the constellation of the Water Snake. In Greek mythology, Apollo, son of Zeus, once sent a raven with a cup to fetch water from a spring for an offering to his father. On the way, the raven was distracted by a fig tree whose fruit was not yet ripe. The black bird waited until the fruit was edible, ate it and only then completed his task. As an excuse for his delay, the raven bird grabbed a water snake and claimed that it had denied him access to the spring. Apollo saw through the lie and sent the raven, the cup and the water snake to heaven as a warning.

In the East another Greek hero, the summer constellation of Hercules, is already making his presence felt. High on the northern night sky is still home to the striking constellation of the Great Bear.

The following sky view is valid for April 1 at midnight, April 15 at 11 p.m. and April 30 at 10 p.m.