In 2015, a joint collaboration project to build a new observatory in Mount Timau, East Nusa Tenggara was initiated between LAPAN, ITB, UNDANA, Kupang Regency and East Nusa Tenggara governments. The site selection is based on preliminary studies conducted on nearby location. This paper presents in situ measurements report on seeing, weather and sky brightness obtained on July 2018 using Differential Image Motion Monitor (DIMM) with 20 cm-telescope, Davis Vantage Vue automatic weather station, and Sky Quality Meter, respectively. Despite the high humidity and foggy condition on the afternoon, the site has good seeing condition with median of 0.93 arcsecond and sky brightness around 22.18 magnitude per arcsecond square after midnight.

We present the result of visual double stars speckle observation in 2012, using 24 inch (60 cm) refractor at the Bosscha Observatory. The objects selected for this observation are calibration candidates, their separations range from 1-7 arc second, and they are located in both northern and southern hemisphere. Seeing effect due to the Earth atmospheric turbulence limits the resolution of ground-based telescopes. Seeing over Bosscha Observatory is generally 1-2 arc second, imposing a limit on visual double star separation below which the system cannot be resolved by long exposure imaging (longer than ∼ 50 ms). Speckle interferometry method is used to resolve double stars with separation below typical size of seeing effect. Series of images are captured in fast short-time exposures (∼ 50 ms) using CCD camera. The result of our first experiment shows that our system can be used to measure separation of 1.8 arc second, with ∆m ≃ 1.Keywords: visual double star, atmospheric turbulence, seeing effect, speckle interferometry, southern hemisphere PACS: 95.75. Mn, 95.75.Kk, 95.85.Kr, 97.80.Di

This work considers the elliptic restricted three-body problem under effects of radiation of the bigger primary, and an oblate spheroid for the smaller primary to mimic an exoplanetary system with a gas giant planet. Under the influences of both effects we look for the existence of the triangular equilibrium points and the influences of the radiation and oblateness on the locations and motion of the points. We set the system in a normalized rotating coordinate system and derive equations of motion for the third infinitesimal object. Our study shows that the effects modify the equilateral/isosceles triangle shape with respect to the primaries. The triangular points also have non-planar motion with period depending on the value of the planet oblateness.

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