Plans for future optical telescopes of diameter more than 10m are based on segmented mirrors, made up of hundreds or even thousands of segments. A challenge for these telescopes is the alignment in piston (cophasing) where phase differences between individual segments have to be reduced to a small fraction of the observing wavelength in order to

The Permanent All Sky Survey (PASS) will consist of arrays of wide angle CCD cameras, that will permanently survey the entire visible sky from several observing sites. Its major objectives are the detection of all giant-planet transits across bright stars and the detection and continuous tracking of any variable or transient phenomena in the full

A single 30 min high-resolution spectrum of the optical counterpart to the black hole candidate XTE J1817-330 (ATEL #714, #733) was acquired with the MIKE echelle spectrograph on the Magellan-Clay telescope at Las Campanas Observatory on Feb 20 2006 08:36 UT. In the blue (red), MIKE covered the wavelength range 3530-5070 (4830-9420) Angstrom with a

Recently, the Galactic center has been reported to be a source of very high energy (VHE) γ-rays by the CANGAROO, VERITAS, and HESS experiments. The energy spectra as measured by these experiments show substantial differences. In this Letter we present MAGIC observations of the Galactic center, resulting in the detection of a differential γ-ray flux

We present 64 photoelectric minima observations of 31 eclipsing binaries. We also report three new times of maxima of three SXPHE type pulsating stars.

We present the results of our long-term monitoring of BD +53°2790, the optical counterpart to the X-ray source 4U 2206+54. Unlike previous studies that classify the source as a Be/X-ray binary, we find that its optical and infrared properties differ from those of typical Be stars: the variability of the V/R ratio is not cyclical; there are