Related papers: Astrometric accuracy during the past 2000 years
The current state of cosmology is easy to summarize: a very successful standard model -- the hot big-bang cosmology -- that accounts for the evolution of the Universe from 10^{-2} sec until the present; bold ideas based upon early-Universe…
In real telescopes, the optical parameters evolve with time, and the degradation is often not uniform. This introduces variations in the image profile and therefore photo-centre displacements which, unless corrected, may result in…
Astrometric space missions like Gaia have stimulated a rapid advance in the field of relativistic astrometry. Present investigations in that field aim at accuracies significantly less than a microarcsecond. We review the present status of…
In its all-sky survey, the ESA global astrometry mission Gaia will perform high-precision astrometry and photometry for 1 billion stars down to $V = 20$ mag. The data collected in the Gaia catalogue, to be published by the end of the next…
Astrometry as a technique has so far proved of limited utility when employed as either a follow-up tool or to independently search for planetary mass companions orbiting nearby stars. However, this is bound to change during the next decade.…
Measuring the rate at which the universe expands at a given time -- the 'Hubble constant' -- has been a topic of controversy since the first measure of its expansion by Edwin Hubble in the 1920's. As early as the 1970's, Sandage et de…
This paper is a report from a recent meeting on "the Future of high-resolution imaging in the visible and infrared", reviewing the astronomical drivers for development and the technological advances that might boost performance. Each of the…
Since its emergence two decades ago, astrophotonics has found broad application in scientific instruments at many institutions worldwide. The case for astrophotonics becomes more compelling as telescopes push for AO-assisted,…
Astronomical observing has been greatly simplified by the development and implementation of digital imaging techniques and remote observing. Aperture photometry of CCD data permits photometric measurements to be made routinely with…
The U.S. Naval Observatory Robotic Astrometric Telescope (URAT) is observing the northern sky since April 2012 for an astrometric survey. Multiple overlaps per year are performed in a single bandpass (680$-$750 nm) using the "redlens" 20 cm…
The previously known, 6-yr spectroscopic binary HR 6046 has been speculated in the past to contain a compact object as the secondary. A recent study has re-determined the orbit with great accuracy, and shown that the companion is an evolved…
This chapter provides an overview of the techniques of radio astronomy. This study began in 1931 with Jansky's discovery of emission from the cosmos, but the period of rapid progress began fifteen years later. From then to the present, the…
Over the past century, major advances in astronomy and astrophysics have been largely driven by improvements in instrumentation and data collection. With the amassing of high quality data from new telescopes, and especially with the advent…
In the last decade, neutrino astronomy has taken off with two major breakthroughs, the first observation of high-energy astrophysical neutrinos in 2013 and the first evidence for gamma-rays and neutrinos from a single object published in…
The aim is to document in some detail the last 35 years of meridian circles, a type of instrument with a fundamental role in astronomy for a very long time, and to do so while witnesses are still alive and can contribute. This is about…
Overview of the determination of astronomical distances from a metrological standpoint. Distances are considered from the Solar System (planetary distances) to extragalactic distances, with a special emphasis on the fundamental step of the…
Object cross-identification in multiple observations is often complicated by the uncertainties in their astrometric calibration. Due to the lack of standard reference objects, an image with a small field of view can have significantly…
[Aims] Accurate astrometry is required to reliably cross-match 20th-century photographic catalogues against 21st-century digital surveys. The present work provides modern-era identifications and astrometry for the 801 emission-line objects…
Automatically extracting the geometric content from the hundreds of thousands of diagrams drawn in historical manuscripts would enable historians to study the diffusion of astronomical knowledge on a global scale. However, state-of-the-art…
A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming that the accuracies for nearly all stars brighter than magnitude $\mathrm{Hp}=8$ are improved, by up to a factor 4, compared to the…