The application of celestial navigation based on inclinometer to aircraft in near‐earth space and planetary rovers is a significant development direction. NOVAS source code, auxiliary files, and documentation are available from the USNO website (). In the Version 3.1 C edition, the ephemeris-access functions have been revised for use on 64-bit systems and for improved performance in general. Future versions will expand the functionality of the Python edition to exploit the object-oriented features of Python. The Python edition uses the computational code from the C edition and currently mimics the function calls of the C edition. NOVAS Version 3.1 introduces a Python edition alongside the Fortran and C editions. NOVAS can be easily connected to the JPL planetary/lunar ephemerides (e.g., DE405), and connections to IMCCE and IAA planetary ephemerides are planned. NOVAS algorithms for aberration and gravitational light deflection are equivalent, at the microarcsecond level, to those inherent in the current consensus VLBI delay algorithm. NOVAS Earth orientation calculations match those from SOFA at the sub-microarcsecond level for comparable transformations. Equinox-based quantities, such as sidereal time, are also supported. NOVAS uses IAU recommended models for Earth orientation, including the IAU 2006 precession theory, the IAU 2000A and 2000B nutation series, and diurnal rotation based on the celestial and terrestrial intermediate origins. portions of The Astronomical Almanac and a number of telescope control systems. NOVAS is used for a wide variety of applications, including the U.S. NOVAS also provides access to all of the building blocks that go into such computations. The library can supply, in one or two subroutine or function calls, the instantaneous celestial position of any star or planet in a variety of coordinate systems. ≤1 mas yr−1 for R>17, and are no larger than ∼10 mas yr−1 for R<17 mas yr−1.The Naval Observatory Vector Astrometry Software (NOVAS) is a source-code library that provides common astrometric quantities and transformations to high precision. We show that the zero-point errors in the proper motions are Measurements are shown to be accurate to typically ☑0 mas yr−1 at J,R∼19,18, rising to ±50 mas yr−1 at J,R∼22,21, and are tied to zero using the extragalactic reference frame. celestial coordinates, which are tied to the International Celestial Reference Frame via the Tycho–2 referenceĬatalogue, are accurate to better than ☐.2 arcsec at J,R∼19,18, rising to ☐.3 arcsec at J,R∼22,21, with positional-dependent systematic effects from bright to faint magnitudes at the ∼0.1-arcsec level. Their accuracies by comparison with external data sets using the first release of data, the South Galactic Cap survey. We describe the algorithms employed in the derivation of the astrometric parameters of the data, and demonstrate In this, the third in a series of three papers concerning the SuperCOSMOS Sky Survey, we describe the astrometric properties This supports cold mode accretion where filament galaxies with a large gravitational potential can draw gas from the large-scale structure. We suggest that this is evidence for massive galaxies accreting cold gas from the intrafilament medium that can replenish some HI gas. The HI fraction is measured for different stellar masses and fifth nearest neighbour projected densities ($\Sigma_$. HI spectral stacking of HI Parkes all sky survey observations yields the HI fraction for filament galaxies and a field control sample. This work uses the 6 degree Field Galaxy Survey and the Discrete Persistent Structures Extractor to define the filamentary structure of the local cosmic web. We examine the HI-to-stellar mass ratio (HI fraction) for galaxies near filament backbones within the nearby Universe ($d <$ 181 Mpc). We show that the zeropoint errors in the proper motions are 17 and are no larger than 10 mas/yr for R < 17 mas/yr. The proper motion measurements are shown to be accurate to typically /- 10 mas/yr at J,R=19,18 rising to /- 50 mas/yr at J,R=22,21 and are tied to zero using the extragalactic reference frame. We show that the celestial coordinates, which are tied to the International Celestial Reference Frame via the Tycho-2 reference catalogue, are accurate to better than /- 0.2 arcsec at J,R=19,18 rising to /- 0.3 arcsec at J,R=22,21 with positional dependent systematic effects from bright to faint magnitudes at the /- 0.1 arcsec level. We describe the algorithms employed in the derivation of the astrometric parameters of the data, and demonstrate their accuracies by comparison with external datasets using the first release of data, the South Galactic Cap survey. In this, the third in a series of three papers concerning the SuperCOSMOS Sky Survey, we describe the astrometric properties of the database.
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