Santosh Joshi

TEACHING

For pre-PhD programme courses on following subjects to PhD students of ARIES :

(i) Radio Astronomy
(ii) Stellar Variability
(iii) Helio-seismology and Asteroseismology
(iv) Radiative Process
(v) Stellar Atmosphere
(vi) Mathematical and Statistical Methods
(vii) Stellar Structure and Evolution
(viii) Basic Astronomy and Coordinate System

Apart from the academic activities, I am involved in various developmental activities at ARIES and Devasthal. The on-going instrument developmental activities are outlined below :

• Successful Commissioning of the Time-series PMT and CCD Photometers

  A stable, well characterized detector equipped on one meter class telescopes at photometric site is essential to detect the low-amplitude light variation in stellar objects. For this purpose, we developed a three-channel fast photometer for 1.04-m telescope of ARIES in year 1999 which is being used since then for the time-series photometric observations of the bright (mv > 10 mag) Ap and Am stars. This photometer is based on the low-noise photo-multiplier tubes. Using the observations taken with present instrumental set-up, we discovered and confirmed the pulsational variability in seven Am stars and one Ap star. We have cataloged more than three hundred null results where variation was not detected using our instrumental set-up. To search for the photometric variability in faint stars (mv < 10 mag) stars, the photo-multiplier based photometer is not an ideal detector due to their low-quantum eciency (<30%). Therefore, to detect the mmag light variations in the faint variables we developed a single channel frame-transfer based CCD photometer (512 pixels x 512 pixels) for 4 1.3-m telescope at Devasthal. This instrument is being regularly used since last couple of years to study the transient phenomena such as exo-planets, occultations, short period pulsational variability in A to F-type stars.

• In-house Development of the Time-Series CCD Photometer for the 3.6-m Telescope

  In the collaboration of UK astronomers Prof. Vik Dhillon and Prof. Tom Marsh, we have proposed to develop a three-channel time-series fast CCD photometer for the side port of the 3.6-m telescope, at Devasthal. Using this photometer, one can observed a target in three colors simultaneously and would be useful for precise estimate of basic parameters such as effective temperature, to overcome the serious problems suffered by filter wheel based camera where the stellar objects vary between the exposure in different filters . This instrument would be based on the low-noise, frame transfer CCD mode with high-quality optics and high-time resolution capabilities extended up-to milli-sec to few seconds. The scientific rational could be in the area of asteroseismic study of pulsating variables, time-domain study of the cataclysmic variables, ickering, exo-planets transit and occultation of moon and other stellar system bodies.

• Experience of taking photometric, spectroscopic and polarimetric observations from various telescopes around the globe.
• Well familiar with the optical (IRAF, MIDAS, DAOPHOT), radio (AIPS) and fast-photometric (QED,DRED) astronomical data reduction packages.

• Knowledge of FORTRAN and other programming language.
• Unix, Linux, Windows computer operating systems.
• Comfortable with the plotting packages viz. SM, GNU-plot etc.

I have participated in more than 50 successful observational proposals where more than 250 observing nights were awarded. Out of them, I was principal investigator in more than 20 observational proposals. For the successful implementations of the projects the astronomical observations for the various projects, are carried out from :

1. 0.5-m, 1.0-m, 1.4-m and 1.75-m telescopes at SAAO, South Africa.
2. 1.04-m telescope at ARIES, Nainital.
3. 1.3-m telescope at Devasthal operated by ARIES, Nainital.
4. 1.2-m Mercator telescope at Canary Islands, Spain.
5. 2.34-m Vainu Bappu Telescope at Kavalur Bangalore.
6. 2.0-m Himalayan Chandra Telescope (HCT) at Leh operated by IIA, Bangalore.
7. 2.0-m Girawali Observatory operated by IUCAA, Pune.
8. 2.56-m Nordic Optical Telescope (NOT) at La Palma jointly operated by Denmark, Finland, Iceland, Norway and Sweden.
9. 2.40-m telescope at the Thai National Observatory operated by National Astronomical Research Institute (NARIT), Thailand.
10. 3.6-m Devasthal Optical Telescope (DOT) operated by ARIES, Nainital.
11. 6.0-m telescope at Special Astrophysical Observatory (SAO), Russia.
12. Giant Meter Radio Telescope (GMRT) at Pune operated by Tata Institute of Fundamental Research (TIFR), Mumbai.