« The stars song » (Le Chant des étoiles ***)

Le chant des étoiles *** is a scientific and cultural project of experimental research in astrophysics (radioastronomy), hyper frequency radio communications by amateur radio station F4KLO. The project is conducted by a non profit association Dimension Parabole under contract with Etablissement Public du Parc et de la Grande Halle de la Villette, EPPGHV.

The purpose of the association is the use of a radio-telescope that had been designed and installed in the Parc de La Villette when the Cité des Sciences et de l’Industrie was created in the 1985-1986’s in Paris 19. The radio-telescope instrument was part of a public demonstration project dedicated to astronomy initiated by Michel Charles. It was designed for the detection of radio signals coming from space and more specifically from the H1 hydrogen spectral line of the Galaxy. However, due to some issues, the radiotelescope had never been activated until now.

Radiotelescope bungalows given by LOXAM to ARP75 association in 2010

Back in 2008 the Association des Radioamateurs de Paris (ARP75) signed an agreement with EPPGHV for the recovery of the radiotelescope but could not achieve the project. The succeeding association « Dimension Parabole » has subscribed a new contract with EPPGHV for using the radiotelescope after performing the instrument rehabilitation.

Project goals are multiple. The first one is to establish a cartography of our Galaxy by receiving and measuring signals emitted at the frequency of atomic hydrogen extremely abondant in the universe. This was the original goal when the instrument had been designed for general public astronomy demonstrations.

An optic view of our Galaxy (the Milky Way)

Experimental radiocommunications on hyperfrequencies by radioamateurs may look strange to most people. Amateur radio stations use different means in order to achieve long distance trans horizon communications, such as artificial satellites or other natural objects.

Secondly we intend to perform communications with other radioamateur stations by using the Moon as a reflector for radiosignals. This is called « Earth-Moon-Earth » or « EME » communications.

The third part of the project is to perform radio communications relayed by a transponder module on board a geostationnary satellite. Recently an Amateur Radio satellite designed under the responsability of AMSAT-DL has been launched by a Space-X falcon rocket and put into geostationary orbit. It is located at 26°East. The satellite allows communications between amateur station using telegraphy, telephony and Digital Amateur TeleVision (DATV) modes within a large Earth area (map light gray area).

We thus contribute to personal and collective education, by diffusing scientific knowledge, international exchanges and establish close relationship, without any financial interest as specified in amateur radio regulations by the International Telecommunication Union (ITU).

An amateur experimental radio station with callsign F4KLO is set up in Folie N4 building located in the parc de la Villette close to the radiotelescope. The station is a local club station affiliated to french radioamateur league, the Réseau des Emetteurs Français (REF).

« Le chant des étoiles » project will allow the demonstration of radio astronomy and amateur radio transmissions to general public. It could be used to help science student education and promote relationship throughout countries. Different events will be organized with didactic workshops and demonstrations.

Meanwhile however, as many years passed without maintenance, the antenna mechanical parts have suffered. Rust on one motor reducer and gearings have broken pins when rotation of the antenna was performed during former tests. Remember that no lubrification was done during more than thirty years !

Recently in 2018, Dimension Parabole association requested EPPGHV to provide new underground main power and Ethernet cables to radiotelescope.  DP team awaked the preamplifier located nearby the dipole positionned at the primary focus of the antenna. This was done by injecting a DC voltage into coaxial cable connected to the dipole. The old coaxial cable was partially replaced by a new one. Another preamplifier adjusted to 1200-1400 MHz was finally put in front of a Software Defined Radio receiver.

Received signals captured by the above devices to our surprise already showed a radio image of our Galaxy after being analyzed locally on micro computers. Real time signals level can be surveyed via Dimension Parabole WebSDR. Read details about recently activated reception and first Galaxy map computed on last news dedicated menu.

Damaged declination moto-reductor recently removed to be repaired

While moto-reductor is being serviced and radiotelescope antenna is immobilized toward zenith, the 33 years old preamplifier located near antenna receiving dipole was powered on. This allowed to receive radio signals from our Galaxy neutral atomic hydrogen around 1420,4 MHz while Milky Way passed in front of antenna twice a day due to Earth rotation.

Image computed from Galactic hydrogen 21 cm radio signal

Dimension Parabole is associated with Hackers from Electrolab (Nanterre) that offered to help us repairing the mechanical parts of the telescope instrument antenna. Broken declination motor and reductors are being repaired. This challenging projects needs help in order to face financial obstacles.

Folie N4 Radio Club F4KLO station building close to the radiotelescope

Dimension Parabole is sharing with Internet radio broadcast station *DUUU  the use of one of the red buildings « Folie N4 » located nearby radiotelescope. Radioamateur and radioamateur by satellite stations (callsign F4KLO) are being installed in Folie N4 shared with *DUUU recording studio.

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*** « Le Chant des étoiles » – A french composer, Louis Dandrel, created in 2000, Le Chant des étoiles, a music inspired by pulsars song, where waves captured by radiotelescopes are tranposed.