Armagh Observatory and Planetarium's Stellar Blog!

What is Radio Astronomy?

Our view of the cosmos is biased by the vista that is apparent to our eyes.  This is what the view in what we call the optically visible portion of the spectrum. To the unaided eye it is a view of a universe full of stars, together with five planets, one Moon and of course the Sun. When augmented with a telescope, our eyes can then see a universe full of galaxies – giant cities of stars.

By Armagh Observatory and Planetarium, ago

2019: A Chinese Year of the Moon

The rapidly-approaching 2019 will let us mark a half-century since human beings took the first steps on a body other than the Earth, namely our own Moon. But, come the New Year, lunar exploration is likely to make the headlines for one other reason: a number of robotic spacecraft built by three different nations will attempt to repeat the feat accomplished by the Apollo programme and land on the Moon’s surface.

By Armagh Observatory and Planetarium, ago

Insight on InSight

Some seven months ago, a NASA spacecraft called InSight was launched atop an Atlas 5 rocket and headed to Mars (Figure 1). If all goes well, the spacecraft will land on the Martian surface at around 8pm UK time this Monday 26th November and begin its science investigation. InSight is a fixed lander (see Figure 2 below), a much simpler affair than the Curiosity rover that arrived in 2012 and continues its trek across the floor of Gale crater to this day. Mobility, is however, not required for the specific aim of the mission. 

By Armagh Observatory and Planetarium, ago

IAU puts the Hubble-Lemaître Law to the Vote – an update!

As an earlier Astronotes article reported on, during its XXX General Assembly in Vienna, held in August 2018, the International Astronomical Union (IAU) put forward a draft resolution to rename the Hubble law as the “Hubble–Lemaître law”. The resolution was proposed to recognise Lemaître’s research on the expansion of the Universe, and to pay tribute to both Lemaître and Hubble for their fundamental contributions to the development of modern cosmology.

By Armagh Observatory and Planetarium, ago

Exo-Moons and Goblins

The discovery of planets orbiting around other stars has been one of humankinds greatest achievements. The existance of these ‘exo-planets’ can challenge our perception of our place in the universe. Since the first confirmed detection of a planet around another normal star (51 Peg) in 1995, many thousands of planets have been discovered. Indeed, it is likely that most stars will have their own system of planets. It is important in answering the question – is there intelligent life out there?

By Armagh Observatory and Planetarium, ago

What’s up in the sky this October?

October is here! It is one of our favourite months as there is so much more to see in the sky and the nights are getting deliciously darker. One thing to remember when you are stargazing is to wrap up warm when you venture outside. The nights are getting much colder, and with some of the best stargazing occurring in the early hours of the morning, we don’t want anyone catching a chill. Thermals and a thermos filled with hot chocolate or coffee will do the trick. Also don’t forget that we will be starting our Star Tracker evenings in the coming months!

By Armagh Observatory and Planetarium, ago

Hydrogen-Deficient Stars 2018 – Armagh Observatory and Planetarium

September 2018 will see over 50 astronomers from around the world gather at the Armagh Observatory and Planetarium to discuss the latest news about hydrogen-deficient stars. These stars have lost nearly all the hydrogen from which they were made, to leave only nuclear ash. Astronomers want to learn how these rare and short-lived remnants formed, and what drives their spectacular changes in brightness. 

By Armagh Observatory and Planetarium, ago

Measuring the Universe – 150th birthday of Henrietta Swan Leavitt

July 4, 2018 saw the 150th birthday of Henrietta Swan Leavitt (1868 – 1921), one of the most important astronomers of the 20th century. Born in Lancaster, Massachusetts, Leavitt graduated from Radfcliffe College, Harvard, in 1892. She then stayed on at the Harvard College Observatory as a volunteer research assistant. Whilst attempting a graduate degree in astronomy and travelling in Europe, she became ill with grave consequences for her hearing. In 1902, then director, Edward Pickering, invited Henrietta to join the permanent staff at Harvard, where she was assigned to study “variable” stars.

By Armagh Observatory and Planetarium, ago

July Weather Roundup

Armagh Observatory, 3rd August 2018: Armagh Observatory reports that July 2018 was much warmer and sunnier than average, with only slightly less than average total rainfall. The mean temperature was 17.0 degrees Celsius (62.6 Fahrenheit), approximately 2.2 C warmer than the long-term (1796–2010) average July temperature at Armagh and 1.2 C warmer than the most recent (1981–2010) 30- year average. This was the warmest July at Armagh for five years. The warmest day (highest maximum air temperature) was 27.1 C, which occurred on the 4th, followed by 26.7 C on the 22nd. Both these maxima wereslightly more than 80 degrees Fahrenheit. The coldest day (lowest maximum air temperature) was 14.4 C on the 11th. The coolest night (lowest minimum air
temperature) was 7.6 C on the 10th, and the warmest night (highest minimum air temperature) was 16.6 C on the 27th followed closely by 16.5 C on the 23rd. The minimum grass temperature was 0.3 C on the 10th, so there were no ground or air frosts.

By Armagh Observatory and Planetarium, ago

110 Years Since The Tunguska Event 

During the summer every year, we observe the International Asteroid Day (“Asteroid Day” for short) on 30th June. The United Nations has proclaimed it will be observed globally on that date “to raise awareness about asteroids and what can be done to protect the Earth, its families, communities, and future generations from a catastrophic event.” 

While their topics certainly have some overlap, the date for the Asteroid Day was not chosen in acknowledgment of the film Armageddon (which was released on 1st July 1998), but to commemorate a much more real and to this day somewhat mysterious occurrence: the Tunguska event (which would also make a good movie title!). This summer marks the 110th anniversary of what is believed to be the largest impact event on Earth in recorded history. 

By Armagh Observatory and Planetarium, ago

Dark Moon Rising: the total lunar eclipse of 27 July, 2018

The Armagh Observatory and Planetarium are holding a special event to mark the lunar eclipse, coming at almost the same time as the opposition of Mars.  The event has proved so popular that tickets sold out within a couple of hours of being released, so we have written this blog entry to tell you about what will happen if you missed out on obtaining a ticket or are going to try to observe the eclipse from elsewhere.

By Armagh Observatory and Planetarium, ago

Sir Patrick Moore and the First Man on the Moon – 49 years on

July 20 1969 saw, arguably, the most famous event in all of human history when Neil Armstrong stepped onto the surface of the Moon and left his footprints there – a mark still indelibly framed in the lunar dust today, some 49 years later.  It may seem almost as incredible that it is indeed nearly half a century ago that this epochal event occurred, one that united all of humanity for a short while, as we stared at that yellow orb in our night skies to know that one of our species was walking on it surface.

By Armagh Observatory and Planetarium, ago

A new ultra-compact binary star

Approximately every other star in the Milky Way galaxy is in a ‘binary’ system. These binaries are made up of two stars orbiting around a common centre of gravity. The time taken for the stars in the binary to make one revolution is called the ‘orbital period’. Binaries have a wide range of orbital period. The closest stellar system to the Sun is alpha Centauri which has two stars not unlike our Sun orbiting around one another every 80 years. A third member of the system, Proxima Centauri, which is much smaller red dwarf star, orbits around these two stars once every 10,000 years.

By Armagh Observatory and Planetarium, ago