New evidence for ancient Greek astronomer Hipparchus’ lost Star Catalogue has come to light thanks multispectral imaging of a palimpsest manuscript and subsequent decipherment interpretation. This new is the most authoritative date allows major progress in reconstruction Catalogue. In particular, it confirms that was originally composed equatorial coordinates. It also Ptolemy’s not based solely...

We present an all-sky catalogue that aligns and overlays the ROSAT HRI, RASS, PSPC and WGA X-ray catalogues and the NVSS, FIRST and SUMSS radio catalogues onto the optical APM and USNO-A catalogues. Objects presented are those APM/USNO-A optical objects which are calculated with ≥ 40% confidence to be associated with radio/X-ray detections, or which are identified as known QSOs, AGN or BL Lacs,...

We present an all-sky catalogue that aligns and overlays the ROSAT HRI, RASS, PSPC and WGA X-ray catalogues and the NVSS, FIRST and SUMSS radio catalogues onto the optical APM and USNO-A catalogues. Objects presented are those APM/USNO-A optical objects which are calculated with ≥40% confidence to be associated with radio/X-ray detections, or which are identified as known QSOs, AGN or BL Lacs, ...

In this work, decision tree learning algorithms and fuzzy inferencing systems are applied for galaxy morphology classification. In particular, the CART, the C4.5, the Random Forest and fuzzy logic algorithms are studied and reliable classifiers are developed to distinguish between spiral galaxies, elliptical galaxies or star/unknown galactic objects. Morphology information for the training and ...

A catalogue is presented with variable (RR Lyrae, semiregular and Mira) stars located inside field #3 of the Palomar-Groningen Survey at the outer edge of the Sagittar-ius dwarf galaxy. One of the semiregular variables is a carbon star, comparable with those found by Azzopardi et al. (1991). Serendipity provides the suggestion, that their carbon stars might not be located inside, but behind the...

We present Hα photometry for a sample of 95 galaxies in Hickson Compact Groups obtained from observations of 31 groups. The Catalogue lists isophotal and adaptive aperture (Kron aperture) flux measurements for about 75% of the accordant galaxies inside the observed HCGs, 22 out of which are upper limits. Non standard data reduction procedures have been used to obtain the continuum subtracted Hα...

A new method for classification of galaxy spectra is presented, based on a recently introduced information theoretical principle, the information bottleneck. For any desired number of classes, galaxies are classified such that the information content about the spectra is maximally preserved. The result is classes of galaxies with similar spectra, where the similarity is determined via a measure...

We present a high-resolution multi-frequency study of the Small Magellanic Cloud (SMC) region around the X-ray pulsar AX J0105-722. From ROSAT PSPC images we resolve this source into several X-ray sources. We combine X-ray, radio-continuum and optical data to identify the sources: for RX J0105.1-7211 we propose an emission line star from the catalogue of Meyssonier & Azzopardi (1993) in the X-r...