In order to definitely prove the claim by Claeskens et al. (1996A&A...305L...9C) that J03.13 is a doubly imaged quasar, WFPC2 direct imaging and FOS spectroscopy of this compact system have been obtained with HST. These textbook case observations clearly show that J03.13 consists of two point-like images separated by 0.849"+/-0.001" with a

We present Hubble Space Telescope/Wide Field Camera 3 narrow-band imaging of the Hα emission in a sample of eight gravitationally lensed galaxies at z = 1-1.5. The magnification caused by the foreground clusters enables us to obtain a median source plane spatial resolution of 360 pc, as well as providing magnifications in flux ranging from ˜10× to

In the last few years many globular clusters (GCs) have revealed complex color-magnitude diagrams, with the presence of multiple main sequences (MSs), broad or multiple sub-giant branches (SGBs) and MS turnoffs, and broad or split red giant branches (RGBs). After a careful correction for differential reddening, high-accuracy photometry with the

Detecting companions to Cepheids is difficult. In most cases the brightness of the pulsator masks the fainter secondary. Since Cepheids play a key role in determining the cosmic distance scale it is crucial to find binaries among the calibrating stars of the period-luminosity relation. Here we present an ongoing observing project of searching for

We give an overview of a project aiming to identify new eclipsing post common envelope binaries from the Sloan Digital Sky Survey. This work focuses on the methodology used to identify such systems, describes the follow-up observations and reports on the results obtained so far.

In the planning stage of extremely large telescopes, site testing and study of high performance adaptive optics systems plays very important roles. Site testing is a very time consuming task, therefore, we have built a fully automatic device - the CUTE SCIDAR instrument with a user-friendly interface and real time processing. This instrument is