Related papers: A new approach for the heliometric optics
In order to achieve a large deployment of renewable energies, the electricity production costs have to be as low as possible. Many different technologies have been proposed to achieve the best efficiency to cost ratio. One of those is…
Several group in the World followed the solar diameter with dedicated instruments, namely solar astrolabes, since 1974. Their data have been gathered in several observing stations connected in the R2S3 (Reseau de Suivi au Sol du Rayon…
French astronomer Honor\'e Flaugergues compiled astronomical observations in a series of hand-written notebooks for 1782$\unicode{x2013}$1830, which are preserved at Paris Observatory. We reviewed these manuscripts and encoded the records…
For the sake of complete theoretical research of atmospheric refraction, the atmospheric refraction under the condition of lower angles of elevation is still worthy to be analyzed and explored. In some engineering applications, the objects…
We present a compact two-lens HDPE f/1.6 refractor design that is capable of supporting a 28-deg diffraction-limited field of view at 1-mm wavelengths and contrast it to a similar two-lens refractor using silicon lenses. We compare the…
In this draft photometry and astrometry is presented from the Herschel Space Observatory (HSO). This spacecraft orbits the second Lagrangian point (L2) of the Sun -- Earth system, yielding a mean distance of a million miles (~ 1.5 million…
The Shack-Hartmann Wavefront Sensor (WFS) is well-known in the fields of optical metrology, wavefront sensing in astronomy, and ophthalmologic control applications. The purpose of this communication is to bring new insights on the…
GREGOR is a new open solar telescope with an aperture of 1.5m. It replaces the former 45-cm Gregory Coude telescope on the Canary island Tenerife. The optical concept is that of a double Gregory system. The main and the elliptical mirrors…
Henri Deslandres initiated imaging spectroscopy of the solar atmosphere in 1892 at Paris observatory. He invented, concurrently with George Hale in Kenwood (USA) but quite independently, the spectroheliograph designed for monochromatic…
Broad-band observations of the solar photosphere began in Meudon in 1875 under the auspices of Jules Janssen. For his part, Henri Deslandres initiated imaging spectroscopy in 1892 at Paris observatory. He invented, concurrently with George…
The Differential Fourier Holography (DFH) gives an exact mathematical solution of the inverse problem of diffraction in the Fraunhofer regime. After the first publication [1] the Differential Fourier Holography was successfully applied in…
In the era of high-angular resolution astronomical instrumentation, where long and very long baseline interferometers (constituted by many, $\sim$ 20 or more, telescopes) are expected to work not only in the millimeter and submillimeter…
Distant starlight passing through the Earth's atmosphere is refracted by an angle of just over one degree near the surface. This focuses light onto a focal line starting at an inner (and chromatic) boundary out to infinity - offering an…
The Helioseismic and Magnetic Imager (HMI) has just started producing data that will help determine what the sources and mechanisms of variability in the Sun's interior are. The instrument measures the Doppler shift and the polarization of…
From 1997 the Observatorio Nacional has been observing the Sun with an astrolabe in order to study variations on the solar semi-diameter. Till now more than 20.000 observations were done. The observations taken in the year of 2001 were…
Studies are under way to propose a new generation of post-VLTI interferometers. The Carlina concept studied at the Haute- Provence Observatory is one of the proposed solutions. It consists in an optical interferometer configured like a…
Compact objects with a light sphere such as black holes and wormholes can reflect light rays like a mirror. This gravitational lensing phenomenon is called retrolensing and it is an interesting tool to survey dark and compact objects with a…
We use wavefront sensing to characterise the image quality of the the High Resolution Telescope (HRT) of the Polarimetric and Helioseismic Imager (SO/PHI) data products during the second remote sensing window of the Solar Orbiter (SO)…
Levitated dipolar scatterers exhibit exceptional performance as optomechanical systems for observing quantum mechanics at the mesoscopic scale. However, their tendency to scatter light in almost any direction poses experimental challenges,…
Direct Sun light absorption by trace gases can be used to quantify them and investigate atmospheric chemistry. In such experiments, the main optical apparatus is often a grating or a Fourier transform spectrometer. A solar tracker based on…