Related papers: Simple demonstration experiments for astronomical …
The challenge for optical detection of terrestial planet is the 25 magnitude brightness contrast between the planet and its host star. This paper introduces a new pupil design that produces a very dark null along its symmetry axis. By…
Smartphone is a powerful internet connected computer packed with internal sensors that measure sound, light, acceleration and magnetic field strength. Physics teachers can use them as measurement devices to demonstrate science concepts and…
Background. Relative astrometry at or below the micro-arcsec level with a 1m class space telescope has been repeatedly proposed as a tool for exo-planet detection and characterization, as well as for several topics at the forefront of…
Research in astronomy education has uncovered that many learners possess limited and fragmented understanding of stars. The corresponding misconceptions manifest in various areas such as star formation, size, the relationship between stars…
Astrometric observations of microlensing events were originally proposed to determine the lens proper motion with which the physical parameters of lenses can be better constrained. In this proceeding, we demonstrate that besides this…
The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead…
Over the past decade, the BeSSeL Survey and the VERA project have measured trigonometric parallaxes to approximately 250 massive, young stars using VLBI techniques. These sources trace spiral arms over nearly half of the Milky Way. What is…
The exploration of interstellar space will require autonomous navigation systems that do not rely on tracking from the Earth. Here I develop a method to determine the 3D position and 3D velocity of a spacecraft in deep space using a star…
For 100 years since galaxies were found to be flying apart from each other, astronomers have been trying to determine how fast. The expansion, characterized by the Hubble constant, H0, is confused locally by peculiar velocities caused by…
Space debris is a major threat to the satellite infrastructure. A collision with even small particle, e.g. 1 cm of size, can cause a catastrophic event when the parent body, spacecraft or upper stage, will break up into hundreds of…
Multi-epoch radio-interferometric observations of young stellar objects can be used to measure their displacement over the celestial sphere with a level of accuracy that currently cannot be attained at any other wavelength. In particular,…
Of all planet-finding techniques, microlensing is potentially the most sensitive to Earth-mass planets. However, microlensing lightcurves generically yield only the planet-star mass ratio: the mass itself is uncertain to a factor of a few.…
We use a Bayesian approach to derive the distance probability distribution for one object from its parallax with measurement uncertainty for two spatial distribution priors, viz. a homogeneous spherical distribution and a galactocentric…
We present a classroom based activity using a sunrise photograph of Mont Blanc shadow taken from Geneva to estimate the Earth radius. By determining the direction of solar rays relative to the local vertical and accounting for atmospheric…
The use of time--like geodesics to measure temporal distances is better justified than the use of space--like geodesics for a measurement of spatial distances. We give examples where a ''spatial distance'' cannot be appropriately determined…
Classification is a general tool of science; it is used to sort and categorize biological organisms, chemical elements, astronomical objects, and many other things. In scientific classification, taxonomy often reflects shared physical…
We show that space-based microlensing experiments can recover lens masses and distances for a large fraction of all events (those with individual photometric errors <~ 0.01 mag) using a combination of one-dimensional microlens parallaxes…
The A5V star Alcor has an M3-M4 dwarf companion, as evidenced by a novel astrometric technique. Imaging spectroscopy combined with adaptive optics coronagraphy allowed for the detection and spectrophotometric characterization of the point…
Described is an experiment in which a smartphone was caused to move at steady state in a vertical plane, on a path that was nearly circular. During a time interval of data acquisition that encompassed multiple orbits, the acceleration of…
Context. The Gaia satellite will measure highly accurate absolute parallaxes of hundreds of millions of stars by comparing the parallactic displacements in the two fields of view of the optical instrument. The requirements on the stability…