Ⅰ. Observatories in Africa (17)

1. National Research Institute of Astronomy & Geophysics (NRIAG) 

Image Source - Google | Image by - nriag

It is situated in Helwan, Cairo, Egypt & was established in 1839 as Royal Observatory at Bollak, then it was moved to ABBASIA in 1868 before it got finally moved to Helwan in 1903 & is the oldest research institute in North Africa & one of the world heritage sites in Science and Technology. 

Kottamia Astronomical Observatory (1964)

  • Extension of (NRIAG) 
  • Largest telescope in the Arab world. 
  • Also called the Northern eye of astronomy in Africa. 
  • Regarded as a small scientific city  
  • Contains the building of the Telescope with its large dome. 

Dimensions of the Telescope 

  • Body weighs more than 50 tons 
  • Has a tube length of 9 m. 
  • Diameter of the main mirror is 188 cm
  • Has a thickness of almost 30 cm & weighs 2 tons. 

Dimensions of the Dome 

  • Made up of double walls of steel by the Austrian company "Voest"
  • Has a diameter of about 19 m & weighs more than 100 tons. 
  • Revolves around the building upon 26 steel rods 
  • Bottom edges prevent leakage of dust & heat to the interior 
  • This design makes the temperature of the floor not exceed 3 °C even on hot days. 
  • Established by the English World Company "Grubb Parson".


2. High Energy Stereoscopic System (H.E.S.S.) 

Image source - Google | Image by - flickr 

It is located in the Khomas region of Namibia, an area known for its excellent optical quality. It is a system of Imaging Atmospheric Cherenkov Telescope (IACT) that is used to investigate cosmic gamma-rays in the photon energy range of 0.03 eV to 100 eV. The acronym (H.E.S.S.) is taken in honour of Victor Hess, who was the first to observe cosmic rays.

It also emphasizes two main features of the telescope : 

  • Simultaneous observation of air showers with several telescopes under different angles. 
  • Combination of telescopes to a large system to increase the effectiveness of detection of gamma rays. 

It can explore the gamma-ray sources with intensities of a few thousandth parts of the flux of the Crab Nebula. 

Structure of HESS

  • Has five telescopes, four with a mirror of diameter 12m 
  • Arranged in a square at a distance of 120m from each other 
  • One large telescope with a mirror of diameter 28m 
  • Constructed in the centre of the square. 

This system called HESS II observes high gamma-ray energy processes in the universe. The sources that produce gamma rays are :

  1. supernova remnants
  2. active galactic nuclei 
  3. pulsar wind nebulae
It also tests unproven theories like predicted gamma-ray annihilation signals from WIMP dark matter particles & Lorentz invariance predictions of loop quantum gravity. 

Discoveries by HESS

  • In 2004, HESS was the first IAUT experiment to spatially resolve a source of cosmic gamma rays. 
  • In 2005, it had detected eight new high energy gamma-ray sources 
  • In 2014, around 90 sources of Tera-eV gamma rays were discovered. 
  • In 2016, HESS reported deep gamma-ray observations which showed the presence of Peta-eV protons originating from the supermassive black hole at the centre of the Milky Way & therefore it should be considered as a useful alternative to supernova remnants as a source of Peta-eV galactic cosmic rays.