Night Sky - May 2019

6th - 7th May will see the peak of Eta Aquarids meteor shower.The shower is usually active between April 19th and May 28th each year. The radiant, the point in the sky where the Eta Aquarids appear to emerge from, is in the direction of the constellation Aquarius (figure 1). The shower is named after the brightest star of the constellation, Eta Aquarii.

The Eta Aquarids is one of two meteor showers created by debris from Comet Halley (figure 2). The Earth passes through Halley's path around the Sun a second time in October. This creates the Orionid meteor shower, which peaks around October 20th.

Comet Halley takes around 76 years to make a complete revolution around the Sun. The next time it will be visible from Earth is in 2061.

The best time to view the Eta Aquarids shower will be between midnight and 06:00.

Figure 1.

Aquarius is Latin, meaning “water carrier” or “cup carrier”.

Figure 2: Comet Halley on 8th March 1986.

On May 18th there will be a blue Moon (figure 3).

Figure 3: Blue Moon.

The phrase has nothing to do with the actual colour of the Moon, although a literal "blue moon" (the Moon appearing with a tinge of blue) may occur in certain atmospheric conditions: e.g., if volcanic eruptions or fires leave particles in the atmosphere of a size to preferentially scatter red light.

Also on the 18ththe Full Moon is known as the flower Moon. The flower Moon because flowers that bloom during this month. Other names include the Corn Planting Moon and the Milk Moon, it has also been called the Hare Moon.

22nd May will see the conjunction of the Moon and Saturn. The Moon and Saturn will share the same right ascension, with the Moon passing 0°31' to the South of Saturn. The Moon will be 18 days old. At approximately the same time, the two objects will also make a close approach called an appulse (figure 4, when two or more astronomical objects, usually planets or the Moon appear close to one another in the sky).

Figure 4: The centre image shows an appulse between the two objects.

They will be visible in the morning sky, becoming accessible at approximately 01:56, when they rise 7° above South Eastern horizon. They will then reach highest point in the sky at 04:44, 16° above the Southern horizon. They will be lost to dawn twilight at approximately 04:48, 16° above the Southern horizon. The pair will be just too widely separated to fit within the field of view of a telescope, but will be visible to the unaided eye or through a pair of binoculars.

WARNING: Never attempt to view through binoculars, telescope or any optical aid an object close to the Sun. Also, never attempt to view the Sun unaided, doing so may result in immediate and permanent blindness. Always use astronomical approved viewing equipment.

The Stellarium software will assist greatly in locating objects in the sky.

Mark R Smith FRAS


Nuclear Fusion & Astrophysics.