... Let us first find out which way -- rise in spectral resolution with some loss in the S/N ratio or increase in the S/N ratio with a fixed spectral resolution -- is better for the purpose of reduction of equivalent width determination errors. ... N -- number of counts for 1 ? ... line equivalent width, . ... Thus if the spectral resolution is managed to be increased (i.e. to decrease )without loss in the number of counts falling at 1 ?, the equivalent width measurement error is then proportional to . ...

... 7 Comments None 3 0.1 1 10 normalized counts/sec/keV Black (qe16) Red (qe17) 1ES0102 REV 0065 MOS2 1 0.2 0.5 -100 -50 0 sign(d-m)*C channel energy (keV) Figure 3: As previous figure, but for MOS2 4 0 10 20 30 40 0.5­2.0 0.6 0.8 1.0 1.2 1.4 statistical basis: 117 observations relative flux in different bands [Joined fit = 1] pn MOS1 MOS2 RGS1 RGS2 xmmsas_20060628_1801­7.0.0_ccf_pub 0 10 20 30 2.0­10.0 0.6 0.8 ...

... HST . ... HST Overview . ... The GHRS can obtain spectra from about 1150 to 3200 . ... The repeatability of fluxes is even better, being better than 1%; i.e., it is possible to compare measures of the same wavelength in the same star at different times to within 1% for observations with the LSA. ... The source to be observed may be placed in a Large Science Aperture (LSA) or a Small Science Aperture (SSA). ... This means that the SSA is better for obtaining spectra with the best resolution. ...

... The experience of determination of the link between radio sources and dynamical reference frames is presented. To obtain this connection we used a series of very long baseline interferometry (VLBI) observations of the spacecraft Phobos-2 and angularly nearby quasars. ... The dynamical reference frame is determined by equator and equinox of these ephemerides. ... References . ... The relative orientation of the radio and dynamical reference frames can be described by a sequence of three rotations . ...

To main of Laboratory . The research work and design of optical and optical-electronic devices are carries out by laboratory staff: . ... Lens: . ... In the layout 1 prism systems perform functions of dispersive element, corrector of aberrations, optical reducer. ... Spectral range 200 - 400 nm; . ... Back Forward . ... The main corrector's function are compensation of field aberrations of the main spherical mirror of a telescope (diameter of 600 mm, f'=1200 mm) and increase aperture ratio. ...

RELATIVE SUNSPOT NUMBERS Description of Data from SGD Explanation of Data Reports: Relative Sunspot Numbers -- The relative sunspot number is an index of the activity of the entire visible disk of the Sun. ... The provisional daily Zurich relative sunspot numbers, Rz, were based upon observations made at Zurich and its two branch stations in Arosa and Locarno and communicated by M. Waldmeier of the Swiss Federal Observatory. ... This indicates the uncertainty above and below the predicted number. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... Lower panel: The ME spot map of the star in orthographic projection, showing the disc of the star as it would be seen by an observer on the Earth at the labelled rotation phases (see the text). ... We carried out high-resolution spectroscopy and BV(I)C photometric monitoring of the two fastest late-type rotators in the nearby Pictoris moving group, HD 199143 (F7V) and CDтИТ64 1208 (K7V). ...

... Clearly, what we need is big telescopes with high resolution spectrographs, to get good data on QSO absorption-lines. With bigger and better telescopes, you could measure the clustering and 3D distribution of gas in the early universe, by looking at lots of faint QSOs in the same parts of the sky. ... With the high resolutions made possible by big telescopes, you could look at the internal velocity structure of the absorbing clouds. ...

... During execution of attitude quality tests, the two tables of attitude coefficients were generated. This tables related to the same time interval on 18. 04. 1997, but have a different time resolution - 15 and 3 min. Using this tables, we have restored the magnetic field measurement. On this panels the measurement and the model(Tsyg96) magnetic field are plotted. 3 min resolution table turn out availiable to provide the better approach to the model magnetic field. ...

Solar High Resolution Studies . ... Solar Group . ... High Resolution Studies . Small Scale Activity . ... High resolution observations at different heights in the solar atmosphere have emphasized that there is no such thing as a "quiet" Sun (e.g. Schrijver et al., ... This, and the temporal coincidence of other signatures, supports the idea that microflares are indeed just miniature flares, but that one needs a very high resolution in order to observe them (Cauzzi et al., 2003, in preparation) . ...

... Low Polar Orbit . ... Different types of satellite orbits have different uses: while the synchronous orbit is best for communication satellites, Lagrangian point orbits help monitor the solar wind before it reaches Earth. ... Many spacecraft use such orbits, e.g. the US Air Force surveillance satellites of the DMSP series, or the series of French Earth-resources spacecraft SPOT . ... If the satellite then starts near a noon-midnight orbit, it will always pass near noon and near midnight. ...

Magnetic Stars, 2011, pp. ... We discuss a recent detection of a strong, organized magnetic field in the bright, broad­line B2V star, HR 5907, using the ESPaDOnS spectropolarimeter on the CFHT as part of the Magnetism in Massive Stars (MiMeS) survey. ... 2010; Rivinius et al., 2010). ... From our longitudinal magnetic field measurements, we confirm this period, which we adopt as the rotational period of this star (see Fig. 1), making it the fastest rotating, non­degenerate magnetic massive star! ...