Karl Guthe Jansky (USA)
In August 1931 discovers radio waves emanating from the Milky Way. He is considered one of the founding figures of radio astronomy.
1937 - 1951
Pioneers of Radio Astronomy
Grote Reber (USA) builds his own radio telescope. He provides a confirmation of Jansky experiments and he conducts the first sky survey in the radio frequencies at λ=2m (150MHz).
James Stanley Hey (GB) discovers that the Sun radiates radio waves and he locates, for the first time, an extragalactic radio source in the constellation Cygnus.
Harold Irwing Ewen and Edward Mills Purcell (USA) are the first ones to detect radio emissions by neutral galactic hydrogen at λ=21cm.
Radio Astronomy in Italy
"Why don't you build a radio telescope?". With this sentence (it was May 1959, inside the Faculty of Physics in Bologna) prof. Giampiero Puppi approaches Marcello Ceccarelli. This is the starting point of the Italian radio astronomy adventure.
The "First Cylinder" Prototype
In March, the "First Cylinder" (about 10m x 7m) is installed on the roof of "Augusto Righi", Faculty of Physics (BO). In May, the "Medicinoscopio Uno" is built in the countryside of Bologna (under the direction of dott. Giancarlo Setti). His length is 110m x 7 and the mirror is produced with 250 stainless steel wires (for a total amount of 25 km of wire). In June, after the opening ceremony (with the participation of the Minister of Education, G. Medici) the first observations and data collections are performed.
A New Instrument
M. Ceccarelli conceives the idea of a new instrument having a cross-shaped layout. He defines the first specifications:
- Working Frequency: 408MHz.
- East/West Arm: 30m wide, offset configuration.
- North/South Arm: interferometer composed with many "small" and "dense" elements.
- Starting Financing: 600 million Lire (following the rules by ISTAT, they are equivalent to 6,6 million Euros).
In May, the project is officially presented to "O.C.E.D, Symposium on Large Antennae for Radioastronomy" held in Paris.
During the summertime, a campaign to measure the alignment to the cardinals points starts. These measurements are very accurate: 1 mm over 600 m.
The First Framework of E/W Arm
The factory in charge of build the entire framework of the antenna, S.E.E. (located in Lecco), builds (on its construction site) the first part of the framework.
Later in the same year, something goes wrong. Because of delays in financing, M. Ceccareli realizes that the E/W Arm must be halved. The layout is turned from a "cross configuration" to "T configuration".
Starting the Construction
In springtime, the construction of this new instrument officially starts. In August, the first E/W arm frameworks are built At the end of August, all the 23 frameworks of the E/W arm are in position: as M. Ceccarelli says "they are in the sky over Medicina", (in the countryside of Bologna). In September, the construction of the E/W arm focal line, with its 1536 dipoles, begins.
But something goes wrong, again: because of the raw materials high costs, the N/S arm needs to be shortened. It will be 300 m long.
Going on Very Quickly
The works for completing the E/W arm are proceeding very fast. In April, the first portions of the N/S arm are coming to Medicina. In September, the construction of the first receiver is finished. In October, "We are on sky", as A. Braccesi writes on his article "TRA RICORDI E DOCUMENTI: RADIOASTRONOMIA E COSMOLOGIA A BOLOGNA, 1959-1969". Observations begin. Many radio sources are observed, some of them are extremely faint.
In November, on a rainy day, the instrument has its opening ceremony; G. Lercaro (Cardinal of Bologna) and L. Gui (Minister of Education) are among the guests.
The Northern Cross
A similar instrument built in Netherland changes its working frequency from 408 MHz to 1420 MHz. In this way it becomes a "super synthesis system". The same idea is followed by the "One Mile Telescope", the new instrument designed in Cambridge.
The Italian instrument remains the "only one" and "powerful" system for sky surveys of the northern hemisphere. It officially becomes the "Northern Cross".
It becames officially the "Northern Cross".
The Instrument Is Completed
On December 24th, the first data acquisition with the N/S arm is performed. The Northern Cross is finally fully operative.
The First Sky Survey
In springtime, the first sky survey is completed and the first catalogue of 328 radio sources is produced. It is submitted to "Astrophysics Letters" in July.
"Doubling" the N/S Arm
The N/S arm is deeply modified. It is halved in the E/W direction, and "doubled" in N/S direction exploiting the "cut" parts. This is necessary in order to obtain approximately the same resolution on both arms.
The Radio Astronomical Station
The construction of the radio astronomical station buildings starts.
The 32-m Dish
Following the new research trends (VLBI, Very Long Baseline Interferometry) a parabolic dish antenna with a diameter of 32 m is under construction. Italy is now a part of the VLBI Consortium.
32-m Dish Opening Cerimony
A special day for the new parabolic antenna of the Medicina Radio Astronomical Station: the opening ceremony. Only one receiver is present: it is a 10-GHz receiver located in the secondary focus (Cassegrain Focus). The data acquisition system is the "MK2 Terminal", substituted in a few months by the "MK3 Terminal".
1984 - 1986
New Cryogenic Receivers
Three new receivers are implemented in the 32-m dish: C-Band, K-Band and the first generation of S/X-band for Geodynamics.
Mechanical parts are changed (due to aging) in the Northern Cross.
1989 - 1991
For the 32-m dish: new panel supports and installation of an updated S/X/K receiver in the primary focus.
For the Northern Cross: new stainless steel wires for the E/W primary mirror.
Increasing the E/W Arm Sensitivity
In the focal line of the E/W arm new amplifiers are implemented (based on GaAs FET Technology). This is done in order to avoid the cable losses, due to their extension from the focal line to the receiver cabin. The Tsys of the system is now 160 K (previously it was 450 K).
Moreover, a new data acquisition system for Pulsar observation is implemented.
Mechanical Revision of the Northern Cross
A complete mechanical revision is performed. In this context, the modifications are: a review of the mechanical adaptors and a complete repainting of the Northern Cross.
In the primary focus of the 32-m parabolic antenna a new S/X/K/L receiver is installed.
Shoemaker-Levy 9 Comet
In July, the water maser emission (@ 22235.079MHz) is detected during the impact of Comet Shoemaker-Levy9 on Jupiter. This experiment is performed with the 32-m parabolic dish antenna coupled to MPSPEC0, a new spectrometer (completely designed in the Medicina Radio Astronomical Station Labs).
The control room of the 32-m dish is provided with the new data acquisition system MK4.
32-m Dish Upgrade
In order to improve the antenna frequency agility, a new handling system for the primary focus is installed. Rail track, wheels and servo-systems are changed. Moreover, two new receivers are installed: C-Band and K-Band.
SRT, Sardinia Radio Telescope
A new generation radio telescope is planned to be built in Sardinia. It will be a 64-m class radio telescope. It will be a powerful single-dish telescope and it will also join the Medicina and Noto radio telescopes in order to implement a network of instruments (Italian VLBI).
Frequency Agility e SRT Activities
In order to further improve the antenna frequency agility, a new layout of secondary focus receiving systems is implemented. The Vertex Room and all the antenna cabling are renewed.
The SRT construction starts. The Medicina Radio Astronomical Station staff is deeply involved in many project activities.
BEST - 1
BEST (Basic Element for SKA Training) is a single parabolic cylinder of the N/S arm which undergoes an update in order to be exploited for the preliminary phase of the SKA Project (Square Kilometer Array - EU - FP6 - SKADS).
Four receivers are installed in the focal line. The signal path is implemented with monomode optical fibers.
"Marcello Ceccarelli" Visitor Center
The "Marcello Ceccarelli" Visitor Center, adjacent to the Medicina station, opens to the public.
e-VLBI, Upgrade of N/S Arm and New C-Band Receiver
The Medicina 32-m parabolic antenna becomes a part of the e-VLBI Project aimed at distributing the acquired data in "real-time".
The extension of the N/S arm pointing system is updated: now it is 135°. A new and better receiver in C-Band is installed on the 32-m dish.
BEST - 2, Multi-Feed in K Band and ESCS
After the positive results of BEST-1 tests, 7 more parabolic cylinders are updated. Now, the N/S arm has 8 "updated" (4 receivers and monomde optical fiber) elements.
new generation of multi-feed receiver is installed and tested on 32-m parabolic antenna: it has 7 elements working in the range 18-26 GHz (K Band). This receiver is now the only multi-feed working at that frequency in the world. Once tested in Medicina, it will be installed on the SRT. A new antenna control system is developed: ESCS (Enhanced Single-dish Control System). It controls all the operations, such as pointing, scheduling, data acquisition in various observation modes.
BEST - 3 Low: LOFAR
A part of the E/W focal line is updated by changing the dipoles with 18 log periodic antennas (120-240 MHz).
Optical Fiber for the 32-m Dish
The signal path from the receivers to data acquisition systems is switched from coaxial cable to optical fiber.
Space-VLBI Radioastron and C-Band Receiver for SRT
The Medicina 32-m dish becomes a part of the Space-VLBI Radioastron network.
The C-Band (5.7-7.7 GHz) for SRT is assembled and tested in the parabolic antenna before its definitive use at the SRT.
A new H-maser (for time reference) is installed on the parabolic antenna Control Room.
New K-Band Dual-Feed Receiver
A smaller version of the 7-elements K-Band receiver (now at the SRT), consisting in two feeds, is installed in the Cassegrain Focus of the parabolic antenna. Meanwhile, the ESCS system is continuously improved.
32-m Dish Maintenance
A significant program of maintenance is performed on the 32-m dish: the antenna is provided with a new Azimuth wheel (damaged by a broken axle), a new subreflector handling system and a restored Elevation rail.