In this proceeding, we present the development of the Optical Ground Support Equipment (OGSE) used for payload-level testing of the Ariel space mission. Ariel is an ESA mission that will use the transit spectroscopy method to observe the atmospheres of nominally ~1000 exoplanets. Ariel is a 1 m class cryogenic (∼ 40 K) space telescope that will be placed in a halo orbit around the Earth-Sun L2 point. To detect atmospheric molecular absorption features, Ariel will produce medium-resolution spectra (R ≥ 15) using three spectroscopic channels covering 1.1 – 7.9 μm as well as having photometric channels covering 0.5 – 1.1 μm. To achieve Ariel’s science goals, the payload requires detailed calibration and performance verification. The payload-level performance verification of the Ariel payload will take place in 2026 in a 5-meter vacuum chamber at the Rutherford Appleton Laboratory’s Space Instruments Test Facility. The payload will be enclosed in a Cryogenic Test Rig (CTR) to provide a space-like (~35 K) thermal environment and is illuminated by the OGSE. The OGSE provides point as well as extended source illumination across Ariel’s full wavelength range. The OGSE design also includes a series of mechanisms and features to enable the various illumination conditions required to test Ariel. Here we report design updates to the OGSE after a preliminary design review (PDR). Since PDR, there have been substantial revisions to the OGSE architecture. In this proceeding, we describe the evolution of the OGSE architecture. The updated OGSE design will then be presented.
The future ARIEL Space Mission aims achieving a photometric precision down to the parts-per-million (ppm) level, over periods longer than ten hours. This required level of sensitivity is crucial to obtain valuable information about the properties of the exoplanet and its atmosphere. The Institute of Astrophysics and Space Sciences is responsible for the development of the visible and near-infrared (Vis-NIR) illumination sub-system, integrated in ARIEL’s Optical Ground Support Equipment (OGSE). This study presents an in-depth analysis of two main component of the Vis-NIR illumination sub-system: a Quartz Tungsten-Halogen (QTH) calibration light source and an extended Indium Gallium Arsenide (InGaAs) reference detector, tested under cryogenic conditions. It is shown that these two components are compliant with the ARIEL's requirements, allowing the mission to obtain spectroscopic and photometric time series with the stability needed to identify signal variations from 20 ppm to 100 ppm, over a 10-hour observation period.
Mid-infrared observations are a vital tool for the study of a wide range of astrophysical phenomena. However, ground-based mid-infrared detectors must overcome the challenge of the overwhelming thermal background from sky and telescope emissions making them prohibitively costly for smaller (< 3 m) facilities. We describe the design and testing of a simple prototype, low-cost 10 µm imaging instrument built around an uncooled microbolometer camera. The instrument incorporates adjustable germanium re-imaging optics to rescale the image to an appropriate plate-scale for 1−2 m class telescopes and uses a gold coated chopping mirror to remove overwhelming sky background contributions. The instrument was tested with a programme of observations of bright mid-infrared sources on the 2 m Liverpool Telescope and the 1.52 m Carlos Sanchez Telescope. With these observations we confirm the instrument can be used for diffraction-limited imaging and has a photometric stability of ~10 %. We report an in-practice sensitivity limit of ~600 Jy, and a theoretical sensitivity limit of ∼ 450 Jy based on the noise equivalent differential temperature of the microbolometer system.
Astro-Ecology couples ‘off the shelf’ infrared imaging technology and astronomy instrumentation techniques for application in the field of conservation biology. Microbolometers are uncooled, infrared systems that image in the thermal-infrared range (8-15μm). These cameras are potentially ideal to use for the detection and monitoring of vulnerable species and are readily available as ’off the shelf’ systems. However to optimise the quality of the data for this purpose requires thorough detector calibration to account for the systematics that limit readout accuracy. In this paper we apply three analogous, standard astronomical instrumentation techniques to characterise the random and spatial noise present in a FLIR Tau 2 Core thermal-infrared camera. We use flat fielding, stacking and binning to determine that microbolometer FPAs are dominated by large structure noise and demonstrate how this can be corrected by subtracting median stacks of flat field exposures.
Using thermal infrared detectors mounted on drones, and applying techniques from astrophysics, we hope to support the field of conservation ecology by creating an automated pipeline for the detection and identification of certain endangered species and poachers from thermal infrared data. We test part of our system by attempting to detect simulated poachers in the field. Whilst we find that we can detect humans hiding in the field in some types of terrain, we also find several environmental factors that prevent accurate detection, such as ambient heat from the ground, absorption of infrared emission by the atmosphere, obscuring vegetation and spurious sources from the terrain. We discuss the effect of these issues, and potential solutions which will be required for our future vision for a fully automated drone-based global conservation monitoring system.
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