Related papers: Learning from Galileo's errors
All anomalous velocity increases until now observed during the Earth flybys of the spacecrafts Galileo, NEAR, Rosetta, Cassini and Messenger have been correctly calculated by computer simulation using an asymmetric field term in addition to…
Johannes Hevelius's 1662 Mercurius in Sole Visus Gedani contains a table of magnitudes and apparent telescopic diameters of nineteen stars. The data conform to a simple model, suggesting that Hevelius produced what is essentially a table of…
Stellar occultations provide a powerful tool to explore objects of the outer solar system. The Gaia mission now provides milli-arcsec accuracy on the predictions of these events and makes possible observations that were previously…
Trans-Neptunian objects (TNOs) and Centaurs are remnants of our planetary system formation, and their physical properties have invaluable information for evolutionary theories. Stellar occultation is a ground-based method for studying these…
The reports from 2008: "Astrometry and optics during the past 2000 years", are available at arXiv and at my website: www.astro.ku.dk/~erik/History.pdf . Here are now further contributions to the history of astrometry related to space…
The Gaia satellite, to be launched in 2012, will offer an unprecedented survey of the whole sky down to magnitude 20. The multi-epoch nature of the mission provides a unique opportunity to study variable sources with their astrometric,…
The solar astrolabe at Observatorio Nacional has been doing a series of solar semidiameter measurements, extending from 1998 up to 2009, to a total of 21640 observations of the Sun. Using the data series it was established the solar radius…
Tidal distension of spacecraft electronics due to spin and solar and galactic gravitation elegantly explains all variations in the anomaly reported by Anderson et al. Contrary to their conclusion, a constant residue seems to be present in…
Distant galaxies encapsulate the various stages of galaxy evolution and formation from over 95% of the development of the universe. As early as twenty-five years ago, little was known about them, however since the first systematic survey…
Hipparchus is considered the greatest astronomer of antiquity. However, his fame is due, more than to what he has done, or said, or written, to what the scientists of some generation or of a few cen-turies later have written of him: above…
In the face of pressing environmental issues in the 21st century, monitoring surface changes on Earth is more important than ever. Large-scale remote sensing, such as satellite imagery, is an important tool for this task. However, using…
In this work, we present the results of a set of numerical simulations carried out to obtain long-duration orbits for a probe around Titania, Uranus' largest satellite. We also propose orbital maneuvers to extend the lifetime of some…
This paper reports the results of an analysis of the Doppler tracking data of Pioneer probes which did show an anomalous behaviour. A software has been developed for the sake of performing a data analysis as independent as possible from…
The Gaia satellite will survey the entire celestial sphere down to 20th magnitude, obtaining astrometry, photometry, and low resolution spectrophotometry on one billion astronomical sources, plus radial velocities for over one hundred…
Radial profiles play a crucial role in the analysis and interpretation of astronomical data, facilitating the extraction of spatial information. However, highly customizable (for different scenarios) measurements over each elliptical…
A well constrained estimate of the distance remains one of the main factors to properly interpret the observations of accreting X-ray pulsars. Since these objects are typically well studied, multiple distance estimates obtained with…
Sundials and gnomons pointing out dates and times are a beautiful reminder of how we understand the movement of the Sun and use it to structure day and year. They also encapsulate the basic astronomical knowledge and concepts of the…
Stellar distances constitute a foundational pillar of astrophysics. The publication of 1.47 billion stellar parallaxes from Gaia is a major contribution to this. Yet despite Gaia's precision, the majority of these stars are so distant or…
In this paper we address the following question: do the recent advances in the orbit determination of the major natural satellites of Saturn obtained with the analysis of the first data sets from the Cassini mission allow to detect the…
We introduce an interactive online resource for use by students and college instructors in introductory astronomy courses. The General Education Astronomy Source (GEAS) online tutor guides students developing mastery of core astronomical…