Abstract.A new survey for pulsating, chemically peculiar A-and F-type stars in the northern hemisphere has been initiated using the 1-m telescope at Uttar Pradesh State Observatory in Naini Tal. The survey is primarily structured to reveal high-overtone pulsations in chemically peculiar A-F stars, but it is also revealing low-overtone δ Scuti-type pulsations in stars with peculiar colours. This paper describes the scope and methods of the survey. Preliminary observations of 28 candidate stars are presented and the discovery of three new pulsators, HD 12098, HD 13038 and HD 13079, is announced. Null results for the remaining 25 stars are also discussed.

A B S T R A C TWe report results of the observations at the Vainu Bappu Observatory and the Uttar Pradesh State Observatory of eight radio-quiet quasi-stellar objects (RQQSOs) during 1996±99. This is a part of our ongoing programme to search for intranight optical variability in RQQSOs. Additional evidence for very rapid variability in three of the five optically bright and very luminous RQQSOs we had observed earlier, 10492006, 14441408 and 16301377, was found. Of the three newly observed RQQSOs, the data for 00431039 are too noisy to allow conclusions about variability to be drawn, but 07481294 and 08241098 show strong hints of microvariability. We also present a summary of the results from our entire programme to date, which includes observations of 16 radio-quiet QSOs and one radio-weak QSO, and compare the general properties of rapid variability in radio-quiet versus radio-loud AGN as determined from our work and that of several other groups. Observations of this kind are likely to play a key role in understanding the relative contributions of accretion discs and relativistic plasma jets to rapid optical fluctuations of AGN.

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Abstract. Based on an extensive site survey conducted during [1980][1981][1982][1983][1984][1985][1986][1987][1988][1989][1990] in the Shivalik Hills of the Central Himalayan range, a promising site Devasthal has been identified. The longitude and latitude of Devasthal Peak are 79• 41 E and 29• 23 N. It is situated at an altitude of 2540 m and about 50 km by road from Nainital towards East. The surroundings of Devasthal are thinly populated and it is logistically well suited for establishing modern optical observational facilities. The prevailing wind direction at Devasthal is NW. For a large fraction of the night time, variation in the ambient temperature was less than a degree and wind speed was less than 10 m/s. During spectroscopic nights (> 200 in a year) relative humidity is less than 80% for about 70% of the time. During 1997 and 1998 seeing measurements using differential image motion techniques have been carried out close to ground at two locations namely Site 1 and Site 2 in Devasthal. Our observations for Site 1 carried over 88 nights yield a median seeing value of 1. 4. For Devasthal Site 2 observations carried over 37 nights yield a median seeing value of 1. 1. Devasthal Site 2 has therefore been selected for locating a modern 3 m optical telescope.

Abstract.We present the analysis of 65 hours of high speed photometric observations of HD 12098 taken from State Observatory, Naini Tal and Gurushikhar Observatory, Mt. Abu on sixteen nights spanning from November 1999 to November 2000. HD 12098 is the first rapidly oscillating Ap star discovered from the "Naini Tal-Cape survey for northern hemisphere roAp stars". It is the 32nd in the complete list. HD 12098 exhibits one predominant mode of oscillation at ν1 = 2.1738 mHz. The second-most significant frequency in our data is at ν2 = 2.1641 mHz with a 1 cycle/day alias ambiguity. We argue that ν2 is a rotational sidelobe of ν1, rather than an independent pulsation mode. Evidence for the presence of two other frequencies at 2.1807 and 2.3056 mHz is also presented.