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Ram Sagar Aryabhatta Research Institute of Observational Sciences (ARIES) Nainital, India

4-m class New Technology optical telescopes at Devasthal Observatory, Nainital, India. Ram Sagar Aryabhatta Research Institute of Observational Sciences (ARIES) Nainital, India. Outline of the talk. Objectives:- Observational facilities (0.35 – 2.5 µm);

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Ram Sagar Aryabhatta Research Institute of Observational Sciences (ARIES) Nainital, India

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  1. 4-m class New Technology optical telescopes at Devasthal Observatory, Nainital, India Ram Sagar Aryabhatta Research Institute of Observational Sciences (ARIES) Nainital, India

  2. Outline of the talk Objectives:- Observational facilities (0.35 – 2.5 µm); Geographical (Foothills of central Himalayas in India) importance and Multi-wavelength astronomical observing capabilities Installed by 2013 360-cm thin mirror active support 400-cm Liquid mirror Conclusion and summary

  3. Future Major Indian Initiatives in Optical Astronomy ASTROSAT – Visible, UV and X-ray astronomy The first Indian multi-wavelength astronomy satellite planned to be launched in 2013 with 5 instruments and a life time of ~5 years. OPTICAL TELESCOPES 4-meter ILMT by 2013 with Belgium, Poland & Canada 3.6-meter to be set up at Devasthal, Nainital by 2013 (Jointly with Belgium) Participate in 30-meter size telescope and build a 10 meter class optical telescope in India by 2025

  4. ~200 km Alt=4 Km Alt=2 Km; Long=79º 27´ E; Lat=29º 22´ N

  5. Geographical location of Devasthal (meaning abode of God) in the Uttarakhand map (courtesy: ISRO)

  6. Characterization of Devasthal site Sagar et al. (2000) AAS 144, 349-362; Stalin et al. (2001) BASI 29, 39-52 Pant et al. (1999) AAS 136, 19-25 • Identified after an extensive survey during 1980-90. • Meteorological parameters like stability of night time temperature, • Relative humidity, Atmospheric pressure, wind speed and cloud coverage. • Differential Image motion monitor (DIMM) for 80 nights in 1998-99 • less than 1 " in a stretch for > 4 hr, 2-4 hr & < 2 hr are 10 %, • 47 % and 43 % respectively. Mean seeing ~ 1.1 arc sec • Micro-thermal measurements at 2, 8 & 11 meters indicate that seeing could be ~0.8 arc sec above 8 meter from the ground. • Rainfall ~ 2000 mm/year; few days snowfall. • Clear nights : ~ 210 /year ~160 photometric • Air temp -4.5 º to 22 º C in a year. Nightly variation ≤ 2 º C. • 3 Km Road provides a state road connectivity to Nainital and other places. • Data connectivity: High speed 2.4 GHz microwave link with 18 Mbps band • width. • A 3 phase dedicated feeder of 11 KV; water and Guest House accommodation.

  7. 130-cm telescope Installed in Oct 2010 Civil work, Dome Design & construction; Electrical installation done by ARIES Fork Equatorial Mounting; open truss Five axis (tip, tilt and 3-axis ) — M2 Friction drives for RA and Dec Control:- dedicated software; GPS ; On site weather monitoring; Pointing accuracy ~ 10” RMS. Photometric observations of Star clusters, galaxies, monitoring Of extra-solar planet and optical Transients like GRBS and Supernovae Sagar et al. (2011) Current Science, Vol 101, No.8, Page 1020-1023

  8. Crab Nebula – SN remnant Pleiades star cluster Kb=0.24 mag; Kv=0.14 mag; Kr=0.08 mag Sky brightness (square arc sec) ~ 21.2 mag in V Limiting magnitude 24.5 mag in R ~30 min; FWHM < 1.5” M82 – Star Burst Galaxy, Hα red colour Orion Nebula – Star Forming Region, BVR colour composite

  9. Earth’s atmosphere Scintillation limited low amplitude flux variations Transiting extra-solar planet WASP-12; V=11.7 mag; 3300 CCD frames of 5 sec each in R; 4.5 hrs observations; Flux variation 17 mmag; Error: < 1 mmagcompared to Manora Peak ~ 3-4 mmag

  10. 3.6 m NTT (2007-2013) Project Cost ~ 20 M Euro (Belgian Contribution is 2 M Euro => 7 % observing time ) ‏ • Key players • The telescope is manufactured by Advanced Mechanical & Optical System (AMOS), • Liege in Belgium. # SPIE 2012:-8444—67, 102, 150, 186 and 8451—82 • Its Observatory Control system and data archiving are being developed by ARIES. • The mirror blank was purchased from SCHOTT, Germany. It is 3.7 meter in • diameter & 165 mm in thickness (22:1). It was figured and polished by • Lytkarino Optical Glass Factory (LZOS), Moscow, Russia. # SPIE 2012:- 8450—176 • The dome/enclosure is being completed by Pedvak & PPS, India. #SPIE 2012:- 8444--152 • The aluminizing unit was delivered by HHV, India. # SPIE 2012:- 8444-152 • The first back end instruments “Faint Object Spectrograph & Camera” and CCD imager • are being designed, assembled and implemented by ARIES. #SPIE 2012:- 8446-38

  11. Basic Configuration • F/9, Ritchey-Chretian (RC) two mirror Cassegrain • focus as an optimization for imaging, spectroscopic and • polarimetric observations. • Science field of view : half degree with Corrector. • 80% encircled energy is in < 0.45 arc sec diameter. • Compact (alt-azimuth) and seeing-limited • (Active optics)‏ Telescope.

  12. Active optics system A low-frequency system that detects and corrects deformations, aberrations or any other phenomena that degrade the image quality. Wave front sensor M1 support system M2 hexapod Telescope control system

  13. The primary mirror • The thermal expansion of glass (“Zerodur”) is ~ 10-7 - 10-8 /K. • The mirror is polished to optical accuracies, in 3.6 meter it is ~33 nm rms. • The primary mirror is not aluminized now and first aluminization will be carried out at Devasthal before the installation.

  14. Primary Mirror Active supports 69 axial actuators (active push only)‏ - 7 nm Resolution - 0.2 N accuracy - 10-1000 N range 24 lateral supports (passive static)‏

  15. Secondary Mirror Hexapod Six -degrees of freedom Tx, Ty, Tz; Rx, Ry, Rz Focus (Tz) – 1 μm Centering (Tx,Ty) – 7.5 μm Tip/Tilt (Rx,Ry) – 1 arcsec

  16. Dec 2011 AMOS Workshop Belgium

  17. Seeing at Factory FWHM = 3.3” When the nights were cold (~8 to 10 C); the seeing was in the range 6”-7”. When the nights were warm (~12 to 14 C); the seeing was ~3”. The best seeing recorded is 2.3” in warm nights. --> It is clear that temperature difference should be minimal to get best seeing. The optics is not fully aligned here; No attempt was made to align the optics further as WFS was not functional at that moment. FWHM = 2.3” <--- ~9.6” ---> Muscida star (+60.7 dec) : 3.3 mag V No Filter.

  18. Telescope Enclosure Dome, Slit and Wind screen M1 ~ 14 meter above ground 25.44 Hz  Pier 14.26 Hz Pier + Tel Diameter – 16.5 m Dome height – 29 m Dome weight – 170 Ton Rotation Speed – 7 m/min Wind speed – 15 m/s (55 m/s)‏ Ventilation – Pier, air flushing, hot air ducts Enclosure design has been completed Construction going on

  19. Coating Plant Al deposition 1000±25 Ǻ R = 92±2 % λ=350-850 nm Completed in December 2011 (HHV Bangalore Workshop)

  20. Instruments 1. Faint object spectrograph and Camera & CCD Imager (Design and CDR are completed. ARIES initiative) 0.35—0.9 µm; Field of View = 14´ X 14 ´ (Imag) & 10´X10´ (Spec) 2. NIR spectrograph (TIFR, Mumbai) - design phase, expected completion – 2014 0.5—2.5 µm; Field of View = 7´ X 7 ´ 3. High resolution optical spectrograph (HERMES-like) (ARIES : in collaboration with Belgium) - design phase; 0.38—0.9 µm; R = 30 K and 60 K 4. Integral Field Unit (IUCAA, Pune) -design phase

  21. 4-meter International Liquid Mirror Telescope Belgium, Canada, Poland and India http://www.aeos.ulg.ac.be/LMT Liège University, AMOS & CSL (Liège Space Center) & ROB (Royal Observatory of Belgium), Canada (Laval University, Montreal University, Toronto, University, Yorke University) ARIES (India) Expected to be installed by Feb 2013 Poels et al. (2012) IAU Symp 285, page 394-396

  22. Upper End CCD Camera Corrector Alignment mechanisms Structure Container Bearing Motor 3-point mount Mirror

  23. Detector will work in Time Delay Integration mode AMOS factory:- Hg thickness 1 mm; surface λ/2 4-m & F/2 + 4K x 4K (15 micron; 0.4 arc-sec/ pix) About 30 arc-sec strip At latitude +290 30’ a half degree strip => 156 square degree About 10 GB data/ night

  24. Expected database towards the Galactic bulge direction _______________________________________________________ Number Objects Timescale Significance __________________________________________________________________ 50/yr Microlense 2-1000 d Galactic structure, dark-matter 10 Million Stars non-variable Stellar populations, Galactic structure 30000 Variables 0.1-3000 d Stellar variability, population tracers 8000 Binaries 0.2-3000 d Stellar evolution, distance estimates 8000 LPVs, SPVs 50-1000 d Galactic Evolution, pulsation physics 5000 spotted RSCVn 15-200 d Stellar magnetic activity and rotation 1400 RR Lyrae 3-28 hr Distance indicators 250 Delta Sct 1-6 hr Pulsation physics, stellar structure 20 Cepheids 2-40 d Cosmological distance indicators 5/yr CVs 1-10 d Accretion physics, nucleo-synthesis _______________________________________________________

  25. Summary and looking forward The 3.6 meter telescope is fully operational at the factory and first light images have been obtained. The optics quality appears excellent under nominal seeing conditions at factory. The mechanical performance of the system also appears very good as compared to the designed and modeled performance. Parts of 4-m ILMT have arrived at the site. Installation of both telescopes is expected to be completed by Q2 of 2013 and first light and initial tests by end of 2013. These facilities can be used for Indo-South African collaborations in both instrumentation and scientific projects. Experience of both countries in building major facilities can also be used under the Indo-South African collaborations.

  26. Thanks for your attention!!

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