The Indian Institue of Astro Physics

The Indian Institute of Astrophysics traces its origin to the Madras Observatory, started in 1786, and moved to Kodaikanal, Tamil Nadu, in 1899. Later renamed as the Kodaikanal Observatory, it has been functioning as a full-fledged solar and stellar observatory. In its present form, the Indian Institute of Astrophysics was set up in 1971 as an autonomous research institution to conduct research in Astronomy, Astrophysics, and allied areas of Physics. The institute is funded by the Department of Science and Technology, Government of India. The main campus is located in Koramangala, in the south-eastern part of the city of Bangalore and its field stations are at Kodaikanal,Kavalur, Gauribidanur , Hanle and Hosakote.

The Observatories

The five observatries of IIAP are:

• VAINU BAPPU OBSERVATORY

Vainu Bappu Observatory

The Kodaikanal Observatory

Gauribidanur Observatory

The Indian Institute of Astrophysics in a joint collaboration programme with the Raman Research Institute operates a radio observatory located at Gauribidanur about 100 km north of Bangalore. Commissioned in 1976, the various facilities at the observatory are actively used to study radio emmision from the sun, pulsars, supernova remnants, galactic and extra-galactic sources.

DECAMETRE WAVE RADIO TELESCOPE
The DWRT is a T-shaped array with a 1.38 km long E-W arm and a 0.45 km long south arm extending from the center of the E-W arm. When the outputs from either arm are correlated in phase, a pencil beam of half-power width 26'x 38'sec (delta -14.1) is obtained where delta is the declination of the source. This correlation beam can be pointed to any direction along the meridian within a declination range of -45 to +75 in steps of 12'. It is possible to track any source for about 42sec (delta) min with this array. The total collecting area of the array is about 250 lambda2. This telescope which is in operation since the early eighties is used for the study of HII regions, continuum and burst emission from the Sun, pulsars and low frequency recombination lines. It was also used to make a one dimensional synthesis map of the sky covering the declination range +70 to -50
GAURIBIDANUR RADIOHELIOGRAPH (GRH)
At present the GRH is the only instrument of its kind in the world at these wavelengths, for dedicated observations of the radio emission from the Sun. It produces pictures of the solar corona at several heights in the range 0.1 - 0.6 above the photosphere. The GRH is a T-shaped array consisting of a 1.28 km long E-W arm and a 0.441 km long South arm starting from the center of the E-W arm. The basic receiving element used in the array is a Log periodic dipole (LPD) which enables in carrying out observations over a wide range of frequencies. The LPDs in the E-W and South arm have been sub-divided into 16 groups each and the outputs from the various groups are correlated in a 1024 channel digital correlator. The angular resolution and sensitivity are about 5'x 8' (delta-14.1) and 100 Jy at 150 MHz. At present, the GRH produces only one map a day at transit. Work is being carried out to install a tracking system which will enable in carrying out observations for about 4 hours ( 2hrs around the meridian) everyday. 
1024 CHANNEL DIGITAL CORRELATOR
The GRH works on the principles of synthesis imaging where the outputs from the different antenna groups are taken separately to the receiver building and then correlated. Since there are 32 antenna groups in the GRH, a 1024 channel receiver is employed to extract the complex visibilities pertaining to all the 512 different baselines. Walsh switching scheme is used to minimise any possible cross-talk between the input signals to the correlator and also any DC offset in the A/D convertor. The observed visibilities are corrected for instrumental/propagation errors using a self-designed calibration scheme which is a hybrid of closure and redundancy techniques.
MAURITIUS RADIO TELESCOPE (MRT)

A large synthesis telescope operating at 150 MHz has been constructed on the island of Mauritius in collaboration with the University of Mauritius and the Raman Research Institute( RRI MRT Page). This instrument which is in operation from 1992 onwards is at present being used for making a synthesis map of the southern sky in the declination range -10 to -70.
LOCATION OF GAURIBIDANUR OBSERVATORY
The Indian Institute of Astrophysics in a joint collaboration programme with the Raman Research Institute operates a radio observatory located at Gauribidanur about 100 km north of Bangalore, India.
Latitude :13 36' 12" 
Longitude :77 26' 07" East 
Local Time :Indian Standard Time, (IST): IST = GMT + 05 30hrs 
REACHING GAURIBIDANUR
Rail Connection :
The nearest railway station to the Observatory is Gauribidanur (100km from Bangalore). Trains bound for Dharmavaram, Hindupur and Mumbai stop at Gauribidanur.
Road Connection :
By road one can reach the Observatory which is situated near a village called Kotaldine which is roughly 8 km from Gauribidanur. The observatory is well-connected by road from Bangalore via Yelahanka, Dodballapur.

The Indian Astronomical Observatory (IAO),

The Indian Astronomical Observatory (IAO), the high-altitude station of IIA, is situated at an altitude of 4500 metres above mean sea level to the north of Western Himalayas. The cloudless skies and low atmospheric water vapour make it one of the best sites in the world for optical, infrared, sub-millimetre and millimetre wavelengths.

THE WORLD'S HIGHEST OBSERVATORY FOR OPTICAL & INFRA-RED ASTRONOMY
2m HCT ANNOUNCEMENT OF OPPORTUNITY 

ABOUT HANLE

The Indian Astronomical Observatory, the high-altitude station of IIA is situated at an altitude of 4500 metres above mean sea level to the north of Western Himalayas. Atop Mt. Saraswati in the vast Nilamkhul Plain of Changthang Ladakh region (4250m above msl) of Jammu & Kashmir State, the site is a dry, cold desert with sparse human population. The cloudless skies and low atmospheric water vapour make it one of the best sites in the world for optical, infrared, sub-millimetre, and millimetre wavelengths.
 

A 2-m optical infrared telescope is installed at the observatory. This telescope is remotely operated from CREST, Hoskote, using dedicated satellite links. In addition, IIA is collaborating with University of Washington, St. Louis, in operating a 0.5-m photometry telescope for continuous monitoring of Active Galactic Nuclei. This telescope will be one of the pair of telescopes constituting Antipodal Transient Observatory. A 0.3-m Differential Image Motion Monitor, a 220-GHz radiometer and an Automated Weather Station have been installed to facilitate continuation of site characterisation.
 

The infrastructure developed by IIA at IAO, Hanle, has paved way towards initiating many new projects in astronomy as well as other paradigms of science. One such example is the study of Geodynamic Deformation Field undertaken jointly by IIA and CMMACS, Bangalore.
 

The Hon'ble Chief Minister of Jammu and Kashmir, Dr Farooq Abdullah inaugurated the satellite communication link on Mt. Saraswati, Indian Astronomical Observatory, Hanle on June 2, 2001
The 2m telescope was dedicated to the nation on 29 August 2001 . 
 

ANTIPODAL TRANSIENT OBSERVATORY, HANLE
 

IIA and McDonell Center for the Space Sciences of Washington University, St. Louis, USA, plan to operate two 0.5-m f/10 Cassegrain telescopes for monitoring Active Galactic Nuclei. One of these telescopes will be located at IAO and the other in Arizona, USA. The two telescopes, 180 deg apart in longitude, would together constitute the Antipodal Transient Observatory.

The telescopes will be equipped with an optical CCD imager and be used in both robotic and remote observing modes. 70% of the telescope time will be used for continuous photometric monitoring of AGN, while the remaining time will be used for photometry of targets of opportunity and other programmes of interest.
 

Specifications :
TELESCOPE INSTRUMENT
Aperture 0.5 metres
Detector 1 K X 1 K CCD of 24 micron pixel
Optics Ritchey-Chretien
Image Scale 0.98 arcsec/pixel
Mount Equatorial
FOV 17 X 17 arcmin
Focus Cassegrain
Filters Bessell UBVRI
F-ratio f/3 primary;f/10 cassegrain
Image scale 41 arcsec/mm
Field of View 7 arcmin; 60 arcmin with corrector
 

GEODYNAMIC DEFORMATION FIELD IN LADAKH
IIA is collaborating with CMMACS, Bangalore, in quantifying the dynamic deformation field in Ladakh, using GPS geodesy with two stations set up by IIA at Leh and Hanle acting as reference stations, together with stations at Bangalore and Kodaikanal. The study provides the station coordinates with sub-cm accuracy and also yields strain rates suffered by the region to elucidate the style and extent of continental deformation in the wake of the Indo-Eurasean convergence of 55 mm/yr.
A 2-m aperture optical-infrared telescope, manufactured by the EOS Technologies Inc., Tucson, Arizona, USA is installed at IAO. The telescope is remotely operated from CREST, Hoskote, via a

satellite link. 
Basic Specifications :
Aperture 2.01 metres
Mirror Material ULE
Optics Ritchey-Chretien
Mount Altitude over azimuth
Focus Cassegrain; provision for Nasmyth
F-ratio f/1.75 primary; f/9 Cassegrain
Image scale 11.5 arcsec/mm
Field of View 7 arcmin; 30 arcmin with corrector
Image quality (zenith) 80% power < 0.33 arcsec; 90% power < 0.73 arcsec dia
Jitter & periodic errors < 0.25 arcsec on each axis
Pointing Accuracy < 0.45 arcsec over 17 arcsec move; <1.5 arcsec for 10 d move
2 M TELESCOPE - OPTICAL CCD IMAGER
The first light optical imager will be built in-house using a 2K X 4K thinned, VISAR coated, SITe ST-002AB CCD with pixel size 15 micron. The image scale and field covered with this CCD are ideally suited to exploit the on-axis 7 arcmin (dia) field of the telescope for sub-arcsecond resolution imaging from the site that offers excellent seeing.
Status
Specifications :
CCD 2048 X 4096 pixels, with pixel size of 15 X 15 micron; thinned, back illuminated, VISAR coated
FOV 5.9 X 11.8 arcmin
Image Scale 0.17 arcsec/pixel
Expected limiting magnitude V=25 (5-sigma detection; t=600s)
Filters Bessell UBVRI, I_c, Z372.7(5.0), 486.1(5.0), 500.7(5.0), 656.3(5.0), 672.4(5.0)664.3(10), 680.4(10), 688.4(10), 696.4(10), 704.4(10), 712.4 (10), 906.9(10) 
2 M TELESCOPE - NEAR IR IMAGER
The near-infrared imager is built around a 512 X 512 HgCdTe array of 18 micron pixel size. The image scale of this instrument will help in subarcsec imaging and reaching out to fainter limits. The instrument has two cameras, one 1:1 camera, and the other 0.5:1 camera giving a wider field.
Status
Specifications :
Wavelength range 0.8-2.5 microns
Detector 18 micron pixel, 512 X 512 format HgCdTe array
Image Scale 0.21 arcsec/pixel (1:1 camera)0.4 arcsec/pixel (0.5:1 camera)
FOV 1.8 X 1.8 arcmin (1:1 camera)3.6 X 3.6 arcmin (0.5:1 camera)
Filters JHK, K_long, H2, CO, Br-gamma, [Fe II] (line & Continuum), K-continuum and CVF
2 M TELESCOPE - HIMALAYA FAINT OBJECT SPECTROGRAPH CAMERA
Himalaya Faint Object Spectrograph Camera is an optical imager cum spectrograph built collaboratively at the Copenhagen University Observatory.
The instrument is a focal reducer type of instrument allowing for a larger field coverage for a given detector, and also low and medium resolution grism spectroscopy. It is possible to shift between the imaging and spectroscopic modes of operation in seconds.

Status
Specifications : click here for full details
Wavelength range 350-900 nm
Detector 2048 X 4096 pixels CCD with pixel size 15 X 15 microns
Collimator focal length 252 mm
Camera focal length 147 mm
Reduction factor 0.58
Spectral resolutions R~150 to R~4500 using a set of 11 grisms
FOV 10 X 10 arcmin (unvignetted) 
Filters Bessell UBVRI372.7(10), 486.1(10), 500.7(10), 656.3(10), 672.4(10)
Performance (not necessarily limiting) Imaging: R=22.2, Mag. err=0.18, exp time=1200s2-sigma detection of ~23.0 mag/arcsec^2 in 40 minutes (H-alpha filter)Spectroscopy: V=18.5, Resln = 300; S/N=22 for exp. time 20min
IAO - CURRENT STATUS
I. 2 Meter Telescope
Telescope tracking tests indicate that the tracking accuracy of 0.5 arcsec over 10 minutes is met at a good fraction of telescope positions, except at higher elevations, where the tracking worsens, resulting in a mean (over all telescope positions) accuracy of 1.38 arcsec over 10 minutes. 
A pointing accuracy of 5 arcseconds has been achieved. 
The image quality is estimated to be about 0.7 arcseconds diameter (80% power).
The autoguider is yet to be implemented. The performance of the autoguider supplied along with the telescope was found to be unsatisfactory. Hence efforts are on to make a new autoguider, which is expected to be available in about a year's time.
II. Instruments
Optical CCD Imager : The new E2V 2K X 4K chip was installed and tested on the telescope. The tests indicate further tuning of the electronics, which is being done in the laboratory. 
HFOSC :
Integration and pre-shipment acceptance tests completed in December 2000 at CUO (Test Report) 
Characterization of the SITe 2K X CCD and integration with the spectrograph completed in January 2001. (The CCD test reports can be obtained from CCD Test Report 
Interface unit design and fabrication completed. 
Instrument shipped and delivered at IIA, Bangalore in August 2001. 
Installation at telescope October 2001. 
Initial tests done in imaging mode in October/November 2001. 
More tests and comissioning done in July-October 2002. 
The instrument can be used in both imaging and spectroscopic mode. 
Near-IR Camera :
Fabrication and integration of the instrument completed. 
Instrument arrived in Bangalore in January 2002. 
User interface software developed at IIA tested. Problem with the controller noticed during the tests. Controller sent to IR Labs for rectification. 
Installation at telescope: March 2003. 
Comissioning tests are underway. 
III. Publications based on data from 2-m HCT
"Optical Photometry of the GRB 010222 Afterglow" R. Cowsik et al, 2001 BASI, 29, 157 
"A Flattening in the Optical Light Curve of SN 2002ap" S.B. Pandey et al, 2003 MNRAS, 340, 375 
"Optical observations of the bright long duration peculiar GRB 021004 afterglow" S.B. Pandey et al, 2003 BASI, 31, 19 (Spectrum of the optical afterglow of GRB 021004) 
"Optical afterglow of the not so dark GRB 021211" S.B. Pandey et al, 2003 A&A (submitted) 
"Night Sky Extinction Measurements at the Indian Astronomical Observatory, Hanle" P.S. Parihar et al, 2003 BASI (submitted) 
"SN 2002ap, the hypernova of class Ic" S.B. Pandey et al, 2003 BASI (submitted) 
Other Science Observations During Telescope Commissioning: 
Photometry of SN 2001X 
Photometry and spectroscopy of SN 2002ap during the late decline phase 
Photometry of the supernova SN 2002hu 
Imaging of galactic starforming regions 
Narrow band imaging of nova GK Persei shell 
The telescope was released for science observations, for about 50% of the time, during May - August 2003. 23 proposals were received, of which 17 were allocated time. 
Extinction and Sky Brightness at IAO
Mean Extinction Values (2000 December - 2003 January) :
U = 0.353 +/- 0.037 
B = 0.209 +/- 0.029 
V = 0.121 +/- 0.032 
R = 0.0823 +/- 0.037 
I = 0.0497 +/- 0.027 
Mean night sky brightness (1995 & 2002) :
U = 23.64 +/- 0.57 
B = 22.94 +/- 0.50 
V = 21.52 +/- 0.21 
R = 20.20 +/- 0.35 
I = 18.60 +/- 0.21 

Image Gallery
http://www.iiap.res.in/iao/gallery.html

CENTRE FOR RESEARCH AND EDUCATION IN SCIENCE AND TECHNOLOGY

Indian Institute of Astrophysics
Shidlaghatta Road, Hoskote 562 114, INDIA
Tel : 915-31952, 31972, 31921, 31466
E-Mail : website@iiap.ernet.in
Last Modified : 28 January 2003

Situated 35 km to the northeast of Bangalore, about 5 km off the Old Madras Road near Hoskote town, is the sprawling 40-acre campus of the Centre for Research and Education in Science and Technology, operated by IIA, Bangalore. 

The campus houses the control room for the remote operations of the 2m Himalayan Chandra Telescope (HCT) at the Indian Astronomical Observatory, Hanle, in addition to laboratories for reserach and development in Laser physics.

The M.G.K. Menon Laboratory for Space Sciences, which is coming up in the campus, will have facilities for development of the UV Imaging Telescope (UVIT), on board the ASTROSAT. 

Graduate Studies 

The Indian Institute of Astrophysics operates a vigorous programme of graduate studies which forms a vital component of research and training. The graduate studies programme is overseen by the BOARD OF GRADUATE STUDIES, which takes care of the academic and related activities of the Ph.D. students as well as the students visiting IIA under the various training programmes. The Institute is also a major partner in the Joint Astronomy Programme (JAP), organized by the Indian Institute of Science.

AMATEUR ASTRONOMY GROUPS

Indian Institute of Astrophysics (IIA), Bangalore is a research institute, conducting active research in the areas of Astronomy, Astrophysics & allied areas of Physics. As a part of the public outreach, the institute provides an opportunity to all the Amateur Astronomy Groups in India to co-ordinate their group activities, through the institute's web page. The amateur groups may share and exchange information about astronomy, intimate other groups about workshops, seminars & conferences through us. Please e-mail information which you would like to be posted to us at website@iiap.ernet.in . We hope this kind of co-ordination will bring all amateur astronomers together to share their knowledge with others.
Lonar Crater, Khagol Mandal, Mumbai (Posted on 08/02/02)
> Some excerpts from a booklet, published on Lonar Crater. Located in the Buldhana District of Maharashtra State, India, Lonar crater is an important geological structure.

Lonar Crater : An Impact Crater

Located in the Buldhana district of Maharshtra State, India (1958|N, 7631|E) Lonar crater is an important geological structure. This crater formed in basalt rock of the Deccan plateau some 35 to 50 thousand years is only of its kind. Though now it is declared as an impact crater, from 1823 when J. E. Alexander pointed out the crater, for almost a century and half the exact type of its origin was a debatable issue. Initially it was thought to be a volcanic crater. Infact the famous geologist G.K. Gilbert in 1896 showed its similarity with the Meteor crater (Barringer crater), Arizona. He had proposed two hypotheses for origin of the Meteor crater: volcanic and meteorite, and was looking for the evidence so that he can come to an answer. Based on negative results of his primary tests he rejected meteorite origin and declared the Meteor crater to be a volcanic one. Later on in the first decade of the 20 th century impact origin of the Meteor crater was proved to be meteorite beyond doubt. But Daniel Moreau Barringer, the mining engineer who studied the crater passionately until his death, had to fight hard for almost 27 years to prove his point. He lost his fortune and perhaps invited his death also in this process. Before his death, he saw his theory of impact origin being vindicated but could not locate the meteorite after spending a fortune on digging for it. The presence of iron meteorite was confirmed by physical and chemical analysis after his death.

> This factor and uniqueness of Lonar crater being the only impact crater on the Earth in basalt rock make it an important structure for study of craters in the solar system. This is the prime reason for conserving the crater, which seem to have been neglected by our community in spite of the unique features of the crater. We will come back to this issue at the end of this chapter.
Geo-morphology of Lonar crater
The crater is formed in the basalt rock of thickness 600-700m. This rock is made of many layers or flows which were laid why volcanic activity at various times, five of such flows are exposed at the crater rim. Thickness of these flows ranges from 5 to 30m. The crater is about 150m deep and has average diameter of 1830m. The elevated rim consists of 25m of bedrock and 5m of ejecta over it. This ejecta blanket is spread over about 1350m away from the crater rim and slopes away by 2-6. The uppermost region of ejecta contains the deposits that were melted due to the impact. Ejecta of any crater is an important factor. The way in which ejecta is spread tells about angle of impact. Spreading pattern for ejecta talks about degree of fluidisation of the rock, volatile components of the rock. This pattern also depends on the planet gravity and presence or absence of atmosphere. Thus if we know how these parameters effect spreading of ejecta then we can conclude about the conditions of impact on that particular planet. And the best place to know these parameters is our earth itself. However, hardly a few craters on the earth are studied well with reference to this point. Lonar crater has surprisingly well-preserved ejecta. Thus this ejecta should be studied further and then it should be conserved also. Crater floor is almost flat & harbours a shallow saline lake.

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The Author  visited Kodai Observatary recently. The article presents quick view of all observataries located around the country- Reference IIAP SITE