Narrow-band filters are often used to constrain the chemical composition of astronomical objects through photometry. A challenge to derive accurate photometry is that narrow-band filters are based on ...interference of multiple reflections and refractions between thin layers of transparent dielectric material. When the light rays reach the surface of a filter not perpendicular to it, they cross the layers obliquely travelling a path longer than the thickness of the layers and different for each inclination. This results in a blue-shift of the central wavelength and a distortion of the transmission curve. Hence, particular care should be taken when narrow band filters are used in presence of small f-numbers and large non-telecentric angles, as frequent in the large field of view (FoV) instruments. Sometimes, the broadening and central wavelength shift of the transmission curve are considered and compensated in the design of filters for instruments with a small f-number. Here we consider the combined effect of small f-number, non-telecentricity and large FoV. Where single spectral lines are considered, a shift in central wavelength or a change in the shape of the transmission curve may introduce an instrumental dispersion in luminosity and in the linked color indices. We found that transmission curves of narrow band filters can be significantly different in shape than the nominal ones. The bottom limits for filters' effective FWHM for each f-number; the monotonic behavior of the blue-shift with distance from the center of FoV; the monotonic quality decrease of the transmission curves and the photometric dispersion introduced by the filters are computationally estimated. This work could represent a useful tool to evaluate the fitness of a particular filter at a particular facility.
Full sky coverage Adaptive Optics on Extremely Large Telescopes requires the adoption of several Laser Guide Stars as references.With such large apertures, the apparent elongation of the beacons is ...absolutely significant.With few exceptions,WaveFront Sensors designed for Natural Guide Stars are adapted and used in suboptimal mode in this context. We analyse and describe the geometrical properties of a class of WaveFront Sensors that are specifically designed to deal with Laser Guide Stars propagated from a location in the immediate vicinity of the telescope aperture. We describe in three dimensions the loci where the light of the Laser Guide Stars would focus in the focal volume located behind the focal plane (where astronomical objects are reimaged). We also describe the properties of several types of optomechanical devices that, through refraction and reflections, act as perturbers for this new class of pupil plane sensors, which we call ingot WaveFront Sensor. We give the recipes both for the most reasonable complex version of these WaveFront Sensors, with 6 pupils, and for the simplest one, with only 3 pupils. Both of them are referred to the ELT case. Elements to have a qualitative idea of how the sensitivity of such a new class of sensors compared to conventional ones are outlined. We present a new class of WaveFront Sensors, by carrying out the extension to the case of elongated sources at finite distance of the pyramid WaveFront Sensor and pointing out which advantages of the pyramid are retained and how it can be adopted to optimize the sensing.
We present the advancements in the development of the scheduler for the Son Of X-shooter instrument at the ESO-NTT 3.58-m telescope in La Silla, Chile. SOXS is designed as a single-object ...spectroscopic facility and features a high-efficiency spectrograph with two arms covering the spectral range of 350-2000 nm and a mean resolving power of approximately R=4500. It will conduct UV-visible and near-infrared follow-up observations of astrophysical transients, drawing from a broad pool of targets accessible through the streaming services of wide-field telescopes, both current and future, as well as high-energy satellites. The instrument will cater to various scientific objectives within the astrophysical community, each entailing specific requirements for observation planning. SOXS will operate at the European Southern Observatory (ESO) in La Silla, without the presence of astronomers on the mountain. This poses a unique challenge for the scheduling process, demanding a fully automated algorithm that is autonomously interacting with the appropriate databases and the La Silla Weather API, and is capable of presenting the operator not only with an ordered list of optimal targets (in terms of observing constraints) but also with optimal backups in the event of changing weather conditions. This imposes the necessity for a scheduler with rapid-response capabilities without compromising the optimization process, ensuring the high quality of observations and best use of the time at the telescope. We thus developed a new highly available and scalable architecture, implementing API Restful applications like Docker Containers, API Gateway, and Python-based Flask frameworks. We provide an overview of the current state of the scheduler, which is now ready for the approaching on-site testing during Commissioning phase, along with insights into its web interface and preliminary performance tests.
