Related papers: Absolute reflectance of a concave mirror used for …
Cherenkov Telescopes are equipped with optical dishes of large diameter -- in general based on segmented mirrors -- with typical angular resolution of a few arc-minutes. To evaluate the mirror's quality specific metrological systems are…
Imaging atmospheric Cherenkov telescopes (IACTs) used for ground-based gamma-ray astronomy at TeV energies use reflectors with areas on the order of 100m$^2$ as their primary optic. These tessellated reflectors comprise hundreds of mirror…
We have developed a method to measure the mirror reflectivity of telescopes. While it is relatively easy to measure the local reflectivity of the mirror material, it is not so straightforward to measure the amount of light that it focuses…
Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures to map the faint Cherenkov light emitted in extensive air showers onto their image sensors. Segmented reflectors fulfill these needs using mass…
The reflector used by an imaging atmospheric Cherenkov telescope (IACT) consists of a tessellated array of mirrors mounted on a large frame. This arrangement allows for a very large reflecting surface with sufficient optical quality for the…
Mirror facets of the H.E.S.S. imaging atmospheric Cherenkov telescopes are aligned using stars imaged onto the closed lid of the PMT camera, viewed by a CCD camera. The alignment procedure works reliably and includes the automatic analysis…
The VERITAS array is a set of four imaging atmospheric Cherenkov telescopes (IACTs) sensitive to gamma rays with energies above 80 GeV. Each telescope is based on a tessellated mirror, 12 metres in diameter, which reflects light from a…
Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill…
The VERITAS array is a set of four imaging atmospheric Cherenkov telescopes (IACTs) sensitive to gamma rays at energies between 85 GeV and 30 TeV. Each telescope is based on a tessellated mirror, 12 metres in diameter, which reflects light…
Imaging Atmospheric Cherenkov Telescopes for very-high energy gamma-ray astronomy need mirror with high reflectance roughly in the wavelength between 300 and 550 nm. The current standard reflective layer of such mirrors is aluminum. Being…
The Cherenkov Telescope Array (CTA) is a forthcoming international ground-based observatory for very high-energy gamma rays. Its goal is to reach sensitivity five to ten times better than existing Cherenkov telescopes such as VERITAS,…
We describe a method that uses total internal reflection at the water-air interface inside a large, transparent tank, to measure the interface's deflections. Using this configuration, we obtain an optical set-up where the liquid surface…
The mirrors installed on Imaging Atmospheric Cherenkov Telescopes like the MAGIC telescopes in La Palma, Canary Islands, are constantly exposed to the harsh environment. They have to withstand wind-induced corrosion from dust and sand,…
Gamma-ray astronomy at energies in excess of 100 GeV is carried out using arrays of imaging Cherenkov telescopes. Each telescope comprises a large reflector, of order 10 m diameter, made of many mirror facets, and a camera consisting of a…
The optics of a number of future X-ray telescopes will have very long focal lengths (10 - 20 m), and will consist of a number of nested/stacked thin, grazing-incidence mirrors. The optical quality characterization of a real mirror can be…
The mirrors of imaging atmospheric Cherenkov telescopes are different from those of conventional astronomical telescopes in several ways, not least in that they are exposed to the elements. One of the issues which may arise is condensation…
Cherenkov threshold detectors (XCET) are used for identifying particles in the experimental areas at CERN. These detectors observe Cherenkov light emitted by charged particles travelling inside a pressurized gas vessel. A key component of…
Mirrors are a subset of optical components essential for the success of current and future space missions. Most of the telescopes for space programs ranging from Earth Observation to Astrophysics and covering all the electromagnetic…
In the $\gamma$-ray Cherenkov Astronomy framework mirror coating plays a crucial role in defining the light response of the telescope. We carried out a study for new mirror coating solutions with both a numerical simulation software and a…
We present total and specular reflectance measurements of various materials that are commonly (and uncommonly) used to provide baffling and/or to minimize the effect of stray light in optical systems. More specifically, we investigate the…