The National Large Solar Telescope

The 2 meter National Large Solar Telescope of India will be the world's most powerful solar telescope on Indiansoil. It will address critical problems in astrophysics, Sun's important influence on Earth and understanding therelease of solar energy into the solar system.

TelescopeStructure

IRT Pier

Instrument Rotator Table

(IRT)

Retractable Dome

Building

Ground Level

Conical Base

Overall tower design with retractable dome

Background

• The National Large SolarTelescope (NLST), to belocated in J&K at an elevationabove 4300 meters, to profitfrom the site’s outstandingatmospheric conditions, withan aperture of 2 meters will bethe world’s largest and mostpowerful telescope to studythe Sun.

• NLST is based upon proventechnologies enabling it tobecome operational in lessthan five years. It will be builtwith international partners,providing access to the state-of-the-art technologies, whileimportant and substantialcomponents will be achievedwithin India.

• NLST will provide the bestimages of the Sun to study theever changing magnetizedsurface, enabling them totackle fundamentalastrophysical questionstowards a predictive capabilityof Sun's impact on the Earth,and assuring Indianinternational preeminence inspace sciences.

J&K

Collage of instruments used in site survey at Merak; clockwise from top right: (1) Solar Differential Image MotionMonitor (SDIMM) and SHAdow BAnd Ranger (SHABAR), (2)sky radiometer, (3) All sky camera, (4) Data acquisitionfacility , (5) Automatic Weather Station (AWS), and (6)micro thermal tower

Site

An extended survey of severalpotential sites has been carried outwith internationally acceptedtechniques and instrumentation.Merak on the shore of Pangong Tso,has been identified as the worldclass site.

This is to take advantage of thewell-known terrestrial atmosphericstabilizing effect of a large body ofwater

Merak

Serrurier/Supporting Struts

Azimuth Axis

Elevation Axis

Azimuth Structure

Frame M1 Mirror Cell

Head ring

Heat Stop

CenterpieceAzimuth axis interface ring

Telescope Axis

Interface with Building structure

Elevation Structure

M2 Unit

Spiders

Schematic structural design of National Large Solar Telescope.

Wind Shield Retractable Dome

Design and Instruments

In order to achieve the requiredmeasurements of the solar magneticfields with high accuracy and sensitivity,a large aperture (2 meter) telescope isnecessary to provide the requisite highspatial resolution and light collecting onthe relevant timescales.

To control atmospheric and thermalperturbations of the observations aninnovative, completely open structure(12m) will allow the telescope toachieve its full potential atop a 20 metertower.

A suite of instruments, located in acontrolled, stable environmentimmediately below the telescope, willanalyze the light from the telescopeusing advanced and well-testedtechniques

Concept for Handling of Secondary Mirror. Concept for Handling of Primary Mirror.

IRT Lab Instruments Handling Concept.

Design and Instruments

The mechanisms responsible for magnetic fieldgeneration and 11 year solar cycle are still notfully understood. Butterfly diagram (Rightpanel) depicting the sunspot distribution withlatitude). The area size distribution is alsoshown. Kodaikanal Observatory is observingthe Sun since 1904 to till date. This centurylong observation has been carried out in WhiteLight (since 1904), Ca K (1904-2007) and in Hα(1912-1999). This figure has been generatedfrom the white light digitized data.

Fine structure of a sunspot and pore region.

MAGNETIC FIELD GENERATION AND THE SOLAR CYCLE

DYNAMICS OF THE MAGNETIZED CHROMOSHPERE

INTERNATIONAL CONTEXT

The heating of the solar atmosphere is intimately related tothe dynamical processes occurring in the magneticnetwork.

Magnetic structures in the solar atmosphere involvecharacteristic spatial scales that are too small to be fullyresolved with the current solar facilities. The magnetic filedplays a crucial role in controlling the dynamics, so theconnection of magnetic field between the photosphere-chromosphere-transition region and corona is mostessential and this will be possible with simultaneousmeasurements of magnetic fields with NLST and Aditya.Aditya is India's first dedicated space scientific mission tostudy the sun. “Aditya-L1mission” will be inserted in a haloorbit around the L1, which is 1.5 million km from theEarth.

Images of different layers of the Sun’stenuous atmosphere, allows to piece thejigsaw puzzle together and provideunderstanding on how magnetic fieldspermeate the dynamic atmosphere.

SUN & INTERPLANETARY MAGNETIC FIELD

The visible surface of the Sun, where the energy generated byfusion of Hydrogen into Helium at the center of the Sunescapes into space, is also the transition from the matter-dominated interior to the magnetic dominated outeratmosphere and interplanetary space. The interplay betweenmodels and observations has highlighted the criticalimportance of high spatial and temporal resolutionobservations of the Sun's magnetic field, velocity field andthermodynamic state with high precision and sensitivity inorder to understand the creation, evolution and explosivedissipation of the magnetic field responsible for the complexstructures of the Sun's atmosphere and interplanetary space.

INTERNATIONAL CONTEXT

NLST will build upon the experience gained in thedevelopment and construction of smaller facilities. It will takea major step forward working in very close technological andscientific collaboration with those projects. The NLST willachieve a significant improvement in spatial resolution andmore importantly, a much higher quantity of light delivered tothe instruments.

DEMOGRAPHICS AND SOCIETAL BENEFITS

The world's largest and the highest performing solartelescope, as an open national facility will attract and developa diverse scientific and technical workforce, as well asconstituting a powerful magnet for talent from around theworld, In addition to the technical challenges, this workforcewill be energized by not only the intrinsic, astrophysicalinterest that the Sun presents, by also that it is arguably theone astronomical body exercising a determining influenceupon humanity. The telescope project will usher in significantnew economic developments in the Ladakh region and offerdirect and indirect employment opportunities for the localpopulation.

An artists impression of the Sun-Earth connection.

High resolution image of the Sunspot and granulationobserved with the 1.6 m NST- BBSO.

Dopplergram Magnetogram Continuum Ca K

ContactProf. Dipankar BanerjeeProject Coordinator (NLST)IIA, Koramangala, 2nd Block,Bengaluru-560034Karnataka, IndiaEmail : dipu@iiap.res.inPhone : +91 80 2254 1431

Dr. B. RavindraProject Manager (NLST)IIA, Koramangala, 2nd Block,Bengaluru-560034Karnataka, IndiaEmail : ravindra@iiap.res.inPhone : +91 80 2254 1328