The Near Earth Object Survey TELescope (NEOSTEL), also known as "Flyeye", is an
astronomical survey
An astronomical survey is a general celestial cartography, map or astrophotography, image of a region of the sky (or of the whole sky) that lacks a specific observational target. Alternatively, an astronomical survey may comprise a set of image ...
and early-warning system for detecting
near-Earth object
A near-Earth object (NEO) is any small Solar System body orbiting the Sun whose closest approach to the Sun ( perihelion) is less than 1.3 times the Earth–Sun distance (astronomical unit, AU). This definition applies to the object's orbit a ...
s sized and above a few weeks before they
impact Earth.
NEOSTEL is a project founded by the
European Space Agency
The European Space Agency (ESA) is a 23-member International organization, international organization devoted to space exploration. With its headquarters in Paris and a staff of around 2,547 people globally as of 2023, ESA was founded in 1975 ...
(ESA), starting with an initial prototype currently under construction at
OHB in Italy. The telescope is of a new "fly-eye" design inspired by the wide field of vision from a
fly's eye. The design combines a single
objective reflector with multiple sets of optics and
CCDs, giving a very wide field of view (around , or 220 times the area of the full moon). When complete it will have one of the widest fields of view of any telescope and be able to survey the majority of the visible sky in a single night. If the initial prototype is successful, three more telescopes are planned, in complementary positions around the globe close to the equator.
In terms of
light gathering power, the size of the primary mirror is not directly comparable to more conventional telescopes because of the novel design, but is equivalent to a conventional 1-metre telescope and should have a
limiting magnitude of around 21.
The project is part of the NEO Segment of ESA's
Space Situational Awareness Programme
The Space Safety Programme, formerly the Space Situational Awareness (SSA) programme, is the European Space Agency's (ESA) initiative to monitor hazards from space, determine their risk, make this data available to the appropriate authorities and w ...
.
The telescope itself should be complete by end of 2024, and installation on Mount Mufara,
Sicily
Sicily (Italian language, Italian and ), officially the Sicilian Region (), is an island in the central Mediterranean Sea, south of the Italian Peninsula in continental Europe and is one of the 20 regions of Italy, regions of Italy. With 4. ...
should be complete in 2025, having been agreed with the
Italian Space Agency
The Italian Space Agency (; ASI) is a government agency established in 1988 to fund, regulate and coordinate space exploration activities in Italy. The agency cooperates with numerous national and international entities who are active in aerospac ...
in October 2018.
The first light of the telescope was on 20 May 2025. Development of the telescope was reported as on track in Feb 2019.
Optics
The
fly eye aspect of the telescope refers to the use of compound optics, as opposed to the single set of optics used in a conventional
telescope
A telescope is a device used to observe distant objects by their emission, Absorption (electromagnetic radiation), absorption, or Reflection (physics), reflection of electromagnetic radiation. Originally, it was an optical instrument using len ...
. Classically, telescopes were designed around a single human observer looking through an
eye piece.
Astrograph
An astrograph (or astrographic camera) is a telescope designed for the sole purpose of astrophotography. Astrographs are mostly used in wide-field astronomical surveys of the sky and for detection of objects such as asteroids, meteors, an ...
s were developed in the 19th century where a
photographic plate
Photographic plates preceded film as the primary medium for capturing images in photography. These plates, made of metal or glass and coated with a light-sensitive emulsion, were integral to early photographic processes such as heliography, d ...
, or later a CCD, records the image, which a human observer can then view. With the human eye no longer directly observing the image there is no longer a restriction on a single viewing point, and
asteroid detection software has become fully automated, so a human observer need not view the majority of images at all.
Light enters the NEOSTEL telescope through the
aperture
In optics, the aperture of an optical system (including a system consisting of a single lens) is the hole or opening that primarily limits light propagated through the system. More specifically, the entrance pupil as the front side image o ...
and is reflected off the primary mirror onto a secondary, consisting of 16 mirrors arranged on a
hexadecagonal pyramid
A pyramid () is a structure whose visible surfaces are triangular in broad outline and converge toward the top, making the appearance roughly a pyramid in the geometric sense. The base of a pyramid can be of any polygon shape, such as trian ...
. The split beam then passes into 16 separate
aspheric lens
An aspheric lens or asphere (often labeled ''ASPH'' on eye pieces) is a lens whose surface profiles are not portions of a sphere or cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens.
...
es and on to 16 corresponding
CCD image sensor An image sensor or imager is a sensor that detects and conveys information used to form an image. It does so by converting the variable attenuation of light waves (as they refraction, pass through or reflection (physics), reflect off objects) into s ...
s.
NEOSTEL uses the 16 CCD cameras to view 45 square degrees of light entering the telescope aperture. The pixel scale is 1.5 arc seconds per pixel across the whole field of view.
Observatory
NEOSTEL's detection capabilities and the
quality of service
Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network, or a cloud computing service, particularly the performance seen by the users of the network. To quantitat ...
it requires (in particular, the use of a fast slewing equatorial mount) mean that a standard telescope dome and observatory design will not be sufficient. Work has been carried out on optimizing the design of the infrastructure layout to solve these problems, whilst minimising the impact of the infrastructure on the environment in
Madonie Regional Natural Park, where Monte Mufara is situated.
See also
*
List of near-Earth object observation projects
List of near-Earth object observation projects is a list of projects that observe Near-Earth objects. Most are astronomical surveys intended to find undiscovered asteroids, and they sometimes find comets.
NEA by survey.svg, Annual NEA discoveri ...
*
Asteroid Terrestrial-impact Last Alert System
The Asteroid Terrestrial-impact Last Alert System (ATLAS) is a robotic astronomical survey and early warning system optimized for detecting smaller near-Earth objects a few weeks to days before they Impact event, impact Earth.
Funded by NASA, an ...
*
Asteroid impact prediction
Asteroid impact prediction is the prediction of the dates and times of asteroids impacting Earth, along with the locations and severities of the impacts.
The process of impact prediction follows three major steps:
# Discovery of an asteroid an ...
References
External links
GAL Hassin: Ente Parco delle Madonie: sì al progetto dell’Osservatorio su Monte Mufara
{{Portal bar, Astronomy, Stars, Spaceflight, Outer space, Solar System
Optical telescopes
Astronomical surveys
Asteroid surveys
Near-Earth object tracking