... Mindful of these biases, I can now explore the relations between the measured rotation periods and various other observables. The hypothesis behind monitoring stellar variability is that active stars have asymmetric spot distributions on their photospheres. ... They found that only stars with rotation periods greater than seven days show variations greater than 0.4 magnitudes at I. Bouvier et al . ... 1993a) demonstrated a relation between X--ray flux and spectral type in ZAMS stars. ...

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. ...

... Bad Astronomy . ... Every few months, one of a series of questions comes up on the USENET group sci.astro involving tides, or the rotation of the Moon, or the recession of the Moon from the Earth. ... Why the Moon's rotation period is the same as the length of time it takes to orbit the Earth (same as number 1, but phrased differently). ... But when this happens, the time it takes for the Earth to rotate once will be slowed to exactly the same time it takes for the Moon to go around the Earth once! ...

The Arcetri Spectral Code for thin plasmas . E.Landi M.Landini 1998, A , 133, 1 . CHIANTI - an atomic database for emission lines. ... E.Landi, M.Landini K.P.Dere, P.R.Young, H.E.Mason, 1999, A , in press . ... E.Landi M.Landini, 1998, A , 340, 265 . ... E.Landi, G.Del Zanna, E.R.Breeveld, M.Landini, B.J.I.Bromage, C.D.Pike, 1998, A , in press . ... M.Landini, A.Brkovic, E.Landi, I.Ruedi, S.Solanki, 1998, Sp.Sci.Rev., in press . ... E.Landi, H.E.Mason, M.Landini, 1998, Sp.Sci.Rev., in press . ...

... Recent Topics . ... MAO main . ... The third-order space-by-time relation . ... Тема: The third-order space-by-time relation . ... The mass m experiences a gravity force toward the sun and . ... will experience the Coriolis force or Coriolis acceleration. ... differentiated space-by-time twice and discovered equation2. ... time differentiation of space-by-time. ... to be described by differentiated forces. ... third-order space-by-time relation. ... understand the third-order space-by-time relation....

Next: The Stopping Radius Up: ``Ecology'' of Magnetic Rotators Previous: A Gravimagnetic Rotator . We shall assume that the rotator is surrounded by an ideally conductive plasma with a density and a sound velocity at a sufficiently far distance from the rotator. ... The following classification   of magnetic rotators     is based on the essential characteristics of the interaction of the plasma surrounding them with their electromagnetic field. ... leading to a spindown   of the rotator. ...

... Singular value decomposition of the matrix A is (a) it's decomposition into singularities (b) it's Fourier transform (c) finding the rotation, which transforms it to diagonal form (d) solution of the eigenvalues problem 4. ... Matrix invertion can be calculated by (a) Matlab (b) dividing by determinant (c) calculation of algebraic complements, traslation and dividing by determinant (d) calculation of minors, traslation and dividing by determinant 2 ...

... Science User Portal . ... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... Survey Telescopes . ... ESO Science Newsletter . ... The UVES measurement values of the relative change of the fine structure constant alpha from the sample of absorption systems, plotted as a function of the redshift and the corresponding look-back time. ... The horizontal long dashed lines show the area of the previous claim of variation of the fine structure constant. ...

LUNAR FIGURE AND LUNAR LIBRATION AS A CLUE TO LUNAR INTERIOR Alexander Gusev, Natasha Petrova, Naufal Rizvanov, Kazan state university & Engelgrdt's astronomical observatory, Dpt. of Astron. ... Kazan 420008, Russia e-mail:Alexander.Gusev@ksu.ru The study of geometrical and dynamical figure of the Moon is one of the important elements of the complex approach to investigation of our satellite. ... Core-mantle interact. and possible convection motion in the Moon", Proc. Int. Conf. ... Proc. of IAU Symp. ...

... 2011 February 22 . Star Size Comparisons . ... Explanation: How big is our Sun compared to other stars? In a dramatic and popular video featured on YouTube , the relative sizes of planets and stars are shown from smallest to largest. ... Note that the true sizes of most stars outside of the Sun and Betelgeuse are not known by direct observation, but rather inferred by measurements of their perceived brightness , temperature , and distance. ... About APOD | ...

... We publish 16 Doppler imaging temperature maps for the years 1994-2002 of the active RS CVn star II Peg. ... Through Doppler imaging we want to study the spot evolution of the star and in particular compare this with previous results showing a cyclic spot behaviour and persistent active longitudes. ... The derived temperature maps are quite similar to the ones obtained earlier with a different methods, the main differences occurring in the spot latitudes and relative strength of the spot structures....

System of astrometric databases of Pulkovo observatory. ... Pulkovo database of observations of visual double stars . ... The 3rd database contains relative positions of selected double and multiple stars, and stars with possible invisible satellites. The database requires catalog of relative positions of visual double stars, based on photographic observations performed since 1960 on Pulkovo 26-inch refractor, and similar catalog based on CCD observations, obtained since 1995. ...

... These trajectories have an initial flight from the Earth to a large distance (of about 1.5 million km), the following passive flight to the Moon's orbit, an approach to the Moon with a decrease of an energy of a particle (spacecraft) selenocentric motion to a negative value and the temporary capture in an elliptic orbit of the Moon's satellite. ... Several trajectories of this type are determined. ... Ivashkin V. V. On optimal trajectories of space flight to the Moon in the Earth--Moon--Sun system. ...

The ESA/ESO Astronomy Exercise Series 2 . The Distance to Messier 100 as Determined by Cepheid Variable Stars . ... The small variations in distance to the individual Cepheid variable stars in the Cloud are negligible compared with the much larger distance to the SMC. ... In this way Cepheid variable stars can be used as one of the 'standard candles' in the Universe that act either as distance indicators themselves or can be used to calibrate (or set the zero point for) other distance indicators. ...

... Fig. 1a,b. Location of slit spectrograms on the HА-line image of IC10. ... Relative abun dances Relative abundances of oxygen are derived using three methods. ... Figures 2, 3, 4 show the distributions of the inferred 12+log(O/H), log(N/O), log(S/O) values along the slits; we averaged the abundances over HII re gions from the catalog of Hodge and Lee [5]. ... Relative oxygen abundance along the slits. ... Relative nitrogen abundance along the slits. ... Relative sulf ur abundance along the slits. ...

... Space flight . ... Space Hotel . ... The program of deployment of small orbital station (SOS) consisting of a family of spacecrafts and module-spacecrafts represents a consecutive realization of flight scenarios with consecutive building up of functions. ... Scenario 1 - the regular and revised spacecrafts of class "Soyuz" - TMSC and MNMSC (MNMSC-cargo, MNMSC-MR) are used, pls. see fig fig.8 . ... The terms of transition to this scenario are determined by terms of readiness of one or another module....

... Numerical Modeling of RadioAstron SRT Temperature Deformations M. Yu. Arkhipov, I. S. Vinogradov, S. B. Novikov, and S. D. Fedorchuk Astro Space Center, Lebedev Physical Institute of the Russian Academy of Sciences, Moscow, Russia e mail: rusengineer@mail.ru Received December 16, 2013 Abstract--The results of modeling the thermal deformations of a space radio telescope's reflecting surface are presented in the paper. ...

Next: ST-ECF Grism Spectrum Software Up: NICMOS Data Calibration and Previous: Photometric Performance of NICMOS . ... Wavelength Calibration of NICMOS Grisms . ... This article describes the wavelength and throughput calibration of the grisms and discusses the photometric performance of the NICMOS grism mode. ... The resolution of the first order spectra on all grisms is about 200 per pixel. ... Spectra were extracted for bright objects with both first and second order spectra on single grism images. ...

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Weekly Bulletin on Solar and Geomagnetic Activity Highlights on 15 - 21.06.2015, Forecast on 22 - 29.06.2015, Carrington Rotations 2164, 2165 (21,44.05; 17,64.06.2015) SUNSPOT-FORMING ACTIVITY OF THE SUN WAS AT THE AVERAGE LEVEL. ... FLARE ACTIVITY WAS AT THE AVERAGE LEVEL ON JUNE, 18, 20 AND 21.06, AT THE LOW LEVEL IN OTHER DAYS. ... HOWEVER 21.06/1645 UT ALL GEOMAGNETIC OBSERVATORIES NOTED ARRIVAL TO THE EARTH OF THE INTERPLA- NETARY SHOCK WAVE FROM FLARE EVENTS ON JUNE 18. ...