... According to the most popular cosmological paradigm, the greater part of the galaxy mass is accumulated in the dark matter halo. ... The polar ring galaxies (PRGs) reveal external rings or disks of gas, dust and stars rotating in a plane roughly perpendicular to the disk of the central galaxy. ... The shape of the dark halo in the model was chosen so as to achieve the best fit to the observed rotation of both galaxies themselves and their polar rings. ... The SPRC-7 galaxy. ...

The azimuth encoder rack gear is mounted on the inside of the azimuth ring girder. The azimuth encoder turns on this gear as the azimuth moves 0 to 720 degrees. ... The software assumes that this arc length along the encoder rack gear is correct (at a constant radius of 127/2 feet). The error in the radius of the rack gear becomes an azimuth error. To measure the error in the azimuth encoder rack gear, jon hagen built a proximity sensor. ... To compute the az encoder runout error: . ...

Next: Quantum Efficiency Correction (a.k.a. Up: ROSAT HRI Recipes Previous: Appearance of new HRI . The mean pulse height analyzer channel (PHA) of a spectral distribution will vary depending on its location on the detector. Below is a method to compare observed data with that of preflight calibration measurements. ... For temporal gain variations, see The HRI Calbration Report . ... Retrieve the gain maps (mean PHA) from anonymous ftp at SAO. ... But don't forget temporal gain variations!] ...

... Its apparent diameter of 18.0 arc minutes corresponds to a linear extension of about 180 light years; Kenneth Glyn Jones mentions an estimate of even 20 arc minutes from deep photographic plates, corresponding to about 200 light years linear diameter. It appears somewhat smaller in amateur instruments, perhaps about 10 minutes of arc. ... Red: 20x3 minute subs, totaling 1 hour . Green: 20x3 minute subs, totaling 1 hour . ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

... Tonight's Sky . ... The Magazine . ... Observing . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... space flight . ... The double star 54 Leonis, spiral galaxy NGC 3198, and emission nebula NGC 3199 . ... Astronomy for Kids . ... Imaging Basics . ... Observing Basics . ... Observing Basics: Distances in Space . ... Expand your observing at Astronomy.com . ... Receive news, sky-event information, observing tips, and more from Astronomy's weekly email newsletter....

... The Moon’s surface is covered with the great number of ring structures - ring mountain (circuses) and by shocked origin (meteoritic) (see the Moon craters and their peculiarity ). ... The temperature in the Moon surface is changing from 400 to 100K. The composition and structure of the Moon. ... There is difference in the mineralogical composition of the Moon and of the Earth: for example, the oxides of iron in the Moon basalt are 25% - more, and titan - 13% more then in the terrestrial. ...

... Flag 1: All those sources with a MASKFRAC column value lower than the value given by parameter mfraclimit will have their first flag set to true, i.e. from 'FFFFFFFFF' to 'TFFFFFFFF'. ... Flag 4: likely spurious extended source in 'circle of influence' of bright point source. This flag will be set if source is extended ( EXT extlimit), has Flag 2 set to true (i.e. is in circle of influence of a bright point source) and the causing source is brighter than counts given by parameter brlimit , i.e.: . ...

... This paper will describe very recent algorithms based on computational geometry which have dramatically reduced the computational complexity of 1) kernel density estimation (which also extends to nonparametric regression, classification, and clustering), and 2) the -point correlation function for arbitrary . ... Problems such as computing kernel density estimates and -point correlation functions correspond to summations over pairs, triples, or in general -tuples of points. ...

... In 1930, Trumpler noticed that linear diameters (LD) of open clusters increase with distance (D) from the Sun. ... Since that time, the interstellar absorption has become one of the best studied factor in astrophysics, and we may hope that current OCL distance scales are free from this LD-D correlation. To verify if this is the case we have chosen several modern OCL distance scales and test them with the same clusters and the same angular diameters that Trumpler had used back in 1930. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. May 14, 1996 . Hubble's Constant and The Expanding Universe (II) . ... American astronomer Edwin Hubble played a major role in this profound discovery, coining the "Hubble constant". ... The value of Hubble's constant was recently the subject of a popular public debate titled "The Scale of the Universe 1996: The Value of Hubble's Constant" . ...

... In result, we obtained the GA constant. ... So, we use the results of the observations of Galactic ob jects to improve A. Our previous estimate of the GA constant (Malkin 2011) yields the values of R0 = 8.2 kpc, 0 = 29.5 km s-1 kpc-1 , and A = 5.02 µas/yr. ... So, the results published in 2008­2013 were used to derive the final estimate of the GA constant. ... We have applied several statistical techniques mostly used in physics and metrology to these data, as described in Malkin (2012, 2013). ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . ... The projected distance of VFTS 682 to the cluster R136 is 29 pc (for an assumed LMC distance of 50 kpc). ... VFTS 682 is located in an active star-forming region, at a projected distance of 29 pc from the young massive cluster R136 in the Tarantula Nebula of the Large Magellanic Cloud. ... Our aim is to obtain the stellar properties, such as its intrinsic luminosity, and to investigate the origin of VFTS 682. ...

... 8, ``Celestial Mechanics'', 2002 High--accuracy modelling of the Earth's gravitational potential from GOCE satellite gradiometry mission M. S. Petrovskaya, A. N. Vershkov Pulkovo Observatory, St. Petersburg, Russia The Earth's gravitational potential is presented in form of a spherical harmon­ ic series with the coefficients C n;m which are the fundamental dynamical constants for the Earth. The set of C n;m for degree 0 џ n џ N and order jmj џ n consti­ tutes a geopotential model. ...

THE STUDY OF THE PIONEER ANOMALY THE STUDY OF THE PIONEER ANOMALY The Pioneer Anomaly : Effect, New Data and New Investigation Slava G. Turyshev Jet Propulsion Laboratory, California Institute of Technology Seminar at the Sternberg Astronomical Institute Moscow State University, Moscow, 6 February 2007 1 THE STUDY OF THE PIONEER ANOMALY THE STUDY OF THE PIONEER ... Are they relevant to the Pioneer anomaly? ...

... Authors: Anne M. Archibald et al. arxiv:0905.0695 Переопределение постоянной Хаббла по данным Космического телескопа, используя дифференциальную шкалу расстояний (A Redetermination of the Hubble Constant with the Hubble Space Telescope from a Differential Distance Ladder) . ... Authors: Jay Anderson, Roeland P. van der Marel . ... Authors: Edward B. Jenkins . ... каталог arxiv:0905.3699 Обновленный каталог галактических остатков сверхновых (A Revised Galactic Supernova Remnant Catalogue) . ...

The direct detection of gravitational waves is one of those events long-expected by physicists that are nevertheless a significant occurrence which excites the world scientific community as if something unexpected has happened. ... Many rumors leaked ahead of the conference, and the fact that something (that is, a signal corresponding to gravitational waves) was discovered by LIGO (Laser Interferometer Gravitational-Wave Observatory) was discussed on the sidelines. ... arXiv:1602.03868 . ...

... Bad Astronomy . ... Bad Astronomy : The seasons are caused by the change in the distance of the Earth to the Sun. ... The change in distance of the Earth to the Sun is a very minor player. ... Well, not completely wrong; certainly the Earth's distance from the Sun has something to do with the temperature, but it is a relatively minor effect. ... Basically, the temperature depends only weakly on distance changes; the temperature goes as the inverse square root of the distance of the planet to the Sun...

Contractions versus extensions of holonomy maps of foliations and applications Julio Reb elo Consider a singular holomorphic foliation F on a pro jective surface. Over the leaves of F we can define real tra jectories over which the parallel transport of F yields a contraction for a natural way of measuring the distance between two leaves. ... It is then natural to consider foliations H containing a tra jectory of "infinite length" and foliations H all of whose tra jectories are of "finite length". ...

... 323, P 295-304 (1997). Abstract . ... 323, P 305-311 (1997). ... 323, P 312-316 (1997). ... 323, P 317-322 (1997). ... 323, P 323-336 (1997). ... 323, P 337-348 (1997). ... 323, P 349-358 (1997). ... 323, P 357-362 (1997). ... 323, P 363-373 (1997). ... 323, P 374-381 (1997). ... 323, P 382-386 (1997). ... 323, P 387-392 (1997). ... 323, P 393-394 (1997). ... 323, P 395-398 (1997). ... 323, P 399-414 (1997). ... 323, P 415-428 (1997). ... 323, P 429-441 (1997). ... helpdesk@link.springer.de . ...