The preservation of the excellent image quality of the 'Roque de los Muchachos' Observatory (ORM) is one of the most important design criteria for the enclosure of the future large telescope. Additionally, the cost of a large telescope and its instrumentation is so high that it would be regrettable if its own enclosure deteriorates the telescope

We obtained K-band (2.0--2.5 mu m) infrared spectra of the visually obscured superluminal source GRS 1915+105 at three different epochs of 1995, at times when it was detected as a hard X-ray source. The three spectra exhibit H I Br gamma (2.167 mu m) and He I (2.058 mu m) emission lines. The spectral morphology, absolute magnitude, and time

Light curves of the very low-mass member of the alpha Persei open cluster, AP J0323+4853, obtained during two different observing runs in 1994 and 1995, display a starspot rotational modulation of period ~7.6h. With a most likely mass of 0.09 Msolar, close to the substellar limit, AP J0323+4853 is the lowest mass star so far for which a photometric

The symbiotic nova RR Telescopii has been observed with the 1.5 m telescope of the Cerro Tololo Inter-American Observatory (CTIO), using the 1.5 m bench-mounted echelle spectrograph in conjunction with a Tektronix CCD. It displays a rich emission-line spectrum, ranging in excitation from O I to [Ni VIII]. We present a list of 491 measured lines

We report intermediate resolution H alpha spectroscopy of the black hole candidate Nova Muscae 1991 during quiescence. We classify the companion star as a K3-K4V which contributes 85 plusmn 6 percent to the total flux from the binary. The photospheric absorption lines are broadened by 106 plusmn 13 km s^-1 with respect to template field stars

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