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Proposed future instruments to be installed on 1.3m telescope:

The optical elements used in instruments for the measurement of the state of polarization are normally polarizers and retarders, although other elements, such as polarization rotating or depolarizing devices, may sometimes be employed. Most elements operate by a controlled application of birefringence, a property of some materials having alternative refractive indices according to the orientation of the electric vector of the incoming radiation. Most of the devices used in the astronomical polarimetry have been described by Serkowski (1974). From the science drives it is clear that a new polarimeter for 1.3-m telescope could be utilized well by carrying out a polarimetric survey in optical wavelengths of the sky available at Devasthal. By looking at the cost versus science output, we have decided to design a polarimeter that will cover an area of 30′ × 30′ field. The rotation of the half-wave plate and the filter wheel will be computer controlled so that automation of the observations can be made. Currently a feasibility study of the design and the availability of the components along with the cost considerations are in progress.

This high-speed time-series CCD photometer will contain a Princeton Instruments based frame transfer CCD camera of 1k x 1k active pixels each of size 13 μm x 13 μm. The CCD is back illuminated and thin for improve blue sensitivity and provides quantum efficiency more than 80% in the wavelength range 4500 Å- 7500 Å. The exposure is to be triggered externally by the pulse generated through a programmable GPS card, makes the time accuracy better than a milli-second. The un-binned full frame can be acquire as fast as 1.1-sec using a low-noise amplifier operated at 1 MHz frequency with an average read out noise of the order of 6.6 e−. The read out speed of 100 kHz leads to a read out noise of 3.7 e− for the exposure time longer than few seconds. This instrument would be optimized to observe variability in pulsating blue variables, planetary transits, flare stars, supernovae etc. with time scales from a fractions of second to several hundred seconds. Our calculations show that for the 1.3-m telescope the photometric precision of 0.01 mag in B-band can be achieved for stars of 14.5-mag and 16.5- mag with exposure time of 1.0-sec and 10.0-sec, respectively. Similarly for the 3.6-m telescope the same precision can be obtained for stars of 17.5 mag and 18.5 mag with same exposure time.