The Isaac Newton Group of Telescopes (ING) consists of the William Herschel
Telescope (WHT), the Isaac Newton Telescope (INT) and the Jacobus Kapteyn
Telescope (JKT). The WHT, with its 4.2m diameter primary mirror, is the largest
in Western Europe. It was first operational in August 1987. It is a general
purpose telescope equipped with instruments for a wide range of astronomical
observations. The INT was originally used at Herstmonceux in the United Kingdom,
but was moved to La Palma in 1979 and rebuilt with a new mirror and new instrumentation.
It has a 2.54m diameter primary mirror and is mostly used for wide-field imaging
and spectroscopy. The JKT has a primary mirror of 1.0m diameter and it was
mainly used for observing relatively bright objects. It ceased science observations
in August 2003 and now it is regularly being used for measuring the atmospheric
turbulence profile above the observatory. Both the INT and the JKT were first
operational in May 1984.
The WHT has an altazimuth mount with a f/2.5 parabolic primary mirror. The
WHT is of classical Cassegrain optical configuration. The paraboloidal primary
mirror is made of a glass-ceramic material (Cervit) having near-zero coefficient
of expansion over the operating temperature range. Instruments can be mounted
at the corrected f/2.81 prime focus, f/11 Cassegrain focus, or either of two
f/11 Nasmyth foci. The primary mirror is made of a glass-ceramic material
(Cervit) having near-zero coefficient of expansion over the operating temperature
range, and it weighs 16.5 tonnes. When not operating at prime focus, a convex
hyperboloidal secondary mirror, made of Zerodur, 1.0m in diameter, directs
the light through a central hole in the primary mirror to the main instrumentation
mounted at the Cassegrain focus beneath the primary mirror cell. The telescope
also incorporates a third main mirror, a flat, angled at 45 degrees, which
can be motor-driven into position at the intersection of the axes, just above
the primary mirror, so that the light from the secondary is diverted sideways
either through one of the altitude bearings to the Nasmyth platforms.
The INT has a primary mirror with a focal ratio of f/2.94. It uses a polar-disc/fork
type of equatorial mount. Instruments can be mounted at the corrected f/3.29
prime or f/15 Cassegrain foci. The optical system of the INT is a conventional
Cassegrain with a paraboloidal primary mirror and a hyperboloidal secondary.
It weighs 4.4 tonnes and it is made of Zerodur.
The JKT has a parabolic primary mirror of diameter 1.0m and a focal length
of 4.596m. It weighs 215kg. It is equatorially mounted, on a cross-axis mount.
The JKT has two optical configurations: Harmer-Wynne and Cassegrain. The former
one uses a f/8 spherical secondary and the latter one a f/15 hyperbolic secondary.
The two optical systems share the same parabolic primary mirror. At present
only the Cassegrain configuration is available and instruments mount at the
The following table shows each telescope’s location:
| ||Latitude||Longitude||Ground floor height|
|WHT || 28° 45' 38.3" N ||17° 52' 53.9" W ||2332m|
|INT ||28° 45' 43.4" N||17° 52' 39.5" W||2336m|
|JKT||28° 45' 40.1" N||17° 52' 41.2" W||2364m|
The ING operates the three telescopes on behalf of the Particle Physics and
Astronomy Research Council (PPARC) of the United Kingdom, the Nederlandse
Organisatie voor Wetenschappelijk Onderzoek (NWO) of the Netherlands, and
the Instituto de Astrofísica de Canarias (IAC) of Spain.
The ING is located at the Observatorio del Roque de Los Muchachos (ORM), on
the island of La Palma, Canary Islands, Spain. The ORM, which is the principal
European northern hemisphere observatory, is owned by the Instituto de Astrofísica
de Canarias. The operation of the site is overseen by an International Scientific
Committee, or Comité Científico Internacional (CCI). Financial
and operational matters of common interest are dealt with by appropriate subcommittees.
The observatory also includes the 3.6m Telescopio Nazionale Galileo, the 2.5m
Nordic Optical Telescope, the 2.0m Liverpool Telescope, the 1.2m Mercator
Telescope, the 60cm telescope of the Swedish Royal Academy of Sciences, the
wide-field imaging facility SuperWasp, the Automatic Transit Circle, the 0.97cm
New Swedish Solar Telescope, the 45cm Dutch Open Solar Telescope, and the
atmospheric imaging Cherenkov 17m Magic Telescopes. Under construction are
a twin to the 17m Cherenkov telescope, MAGIC-2, and the 10.4m Gran Telescopio
The observatory occupies an area of 1.89 square kilometres approximately 2350m
above sea level on the highest peak of the Caldera de Taburiente National
Park, in the Palmeran district of Garafía. La Palma is one of the westerly
islands of the Canarian archipiélago.
The site was chosen after an extensive search for a location with clear, dark
skies all the year around. All tests proved that the Roque de Los Muchachos
is one of the best astronomical sites in the world. The remoteness of the
island and its lack of urban development ensure that the night sky at the
observatory is free from artificial light pollution. The continued quality
of the night sky is protected by law. The mountain-top site has a remarkably
stable atmosphere, owing to the local topography. The mountain has a smooth
convex contour facing the prevailing northerly wind and the air-flow is comparatively
undisturbed, allowing sharp and stable images of the night sky.
Many of the state-of-art telescope and instrument components are custom-built.
New instruments are designed and built by technology groups mainly in the
United Kingdom, the Netherlands, and Spain, with whom the ING maintains close
links, and by astronomers and engineers working at ING.
The International Agreements
The international agreements by which the Roque de Los Muchachos and the Teide
Observatories were brought into existence were signed on La Palma on 26 May
1979. The participant nations at that time were Spain, the United Kingdom, Sweden
and Denmark. Later other European countries also signed the agreements. Infrastructural
services including roads, communications, power supplies as well as meals and
accommodation facilities have been provided by the Spanish side. In return for
the use of the observatory and its facilities all foreign user institutions
make 20 per cent of time on their telescopes available to Spanish observers.
Representatives of the participant institutions meet together as the International
Scientific Committee, or Comité Científico Internacional (CCI).
The inauguration of the Canary Islands observatories took place on 29 June
1985 in the presence of the monarchs and members of the Royal Families of
five European countries, and the Presidents of another two.
The ING Board and the Director's Advisory Committee
The PPARC, the NWO and the IAC have entered into collaborative agreements for
the operation of and the sharing of observing time on the ING telescopes. The
ING Board was set up to oversee the operation of this agreement, to foster and
develop collaboration between astronomers of the United Kingdom, the Netherlands
and Spain, and to ensure that the telescope installations are maintained in
the forefront of world astronomy. In particular, the ING Board oversees the
programme of instrumentation development, determines the programme of operation
and maintenance of the installations, approves annual budgets and forward estimates
and determines the arrangements for the allocation of observing time.
The ING Board at the Gran Telescopio Canarias [
The Director’s Advisory Committee (DAC) assists the observatory in defining
the strategic direction for operation and development of the telescopes. It
also provides an international perspective and acts as an independent contact
point for the community to present its ideas.
Telescope Time and Data Ownership
The construction, operation, and development of the ING telescopes is the
result of a collaboration between the United Kingdom, the Netherlands and
Spain. The site is provided by Spain, and in return Spanish astronomers receive
20 per cent of the observing time on the telescopes. A further 75 per cent
is shared by the United Kingdom, the Netherlands and the IAC. The remaining
5 per cent is reserved for large scientific projects to promote international
collaboration between institutions of the CCI member countries. It is intended
that this time be used for the study of one, or a few, broad topics each year
by several telescopes. This time is allocated by the CCI.
It is the responsibility of the IAC to make the Spanish time available to Spanish
institutions and others, via the Comité para la Asignación de
Tiempos (CAT). The ING Board has delegated the task of time allocation to British
and Dutch astronomers to the PPARC Panel for the Allocation of Telescope Time
(PATT) and the NFRA Programme Committee (PC) respectively. All the above agreements
envisage that observing time shall be distributed equitably over the different
seasons of the year and phases of the Moon.
Notwithstanding the above, any astronomer, irrespective of nationality or affiliation,
may apply for observing time on the ING. Astronomers who are working at an institute
in one of the partner countries should apply through the route appropriate to
their nationality or the nationality of their institute.
Time is allocated in two semesters, from 1 February to 31 July (semester A)
and from 1 August to 31 January (semester B). Decisions on time allocations
are made on the basis of scientific merit and technical feasibility of the proposed
ING policy is that data belongs exclusively to those who collected it for a
period of one year, after which it is available in a common archive for all
). It may be used at any time
for engineering or instrumental investigations in approved programmes carried
out to improve facilities provided at the observatory.
Service observations which are made by support astronomers at the request of
others are similarly treated. However, calibration data may well be used for
more than one observation and may therefore be available in common to several
groups. It may happen that identical or similar service observations are requested
by two or more groups. Requests which are approved before the data are taken
may be satisfied by requiring the data to be held in common by the several groups.
It is up to them how they organise themselves to process, analyse, relate to
other work, and eventually publish the data.
Requests for observations from programmes already executed on the telescopes
should be referred to the original owners of the data, and/or to the data
archive. This is the policy whether or not the data were obtained by PATT,
NFRA PC, or CAT scheduled astronomers, or by service requests.