LOLAS-2: Redesign of an Optical Turbulence Profiler with High Altitude-resolution

Abstract

We present the development, tests and first results of the second generation Low Layer Scidar (LOLAS-2). This instrument constitutes a strongly improved version of the prototype Low Layer Scidar, which is aimed at the measurement of optical turbulence profiles close to the ground, with high altitude-resolution. The method is based on the Generalised Scidar principle which consists in taking double-star scintillation images on a defocused pupil plane and calculating in real time the autocovariance of the scintillation. The main components are an open-truss 40-cm Ritchey-Chrétien telescope, a german-type equatorial mount, an Electron Multiplying CCD camera and a dedicated acquisition and real-time data processing software. The new optical design arXiv:1606.05217v1 [astro-ph.IM] 16 Jun 2016 2 Avila et al. of LOLAS-2 is significantly simplified compared with the prototype. The experiments carried out to test the permanence of the image within the useful zone of the detector and the stability of the telescope focus show that LOLAS-2 can function without the use of the autoguiding and autofocus algorithms that were developed for the prototype version. Optical turbulence profiles obtained with the new Low Layer Scidar have the best altitude-resolution ever achieved with Scidar-like techniques (6.3 m). The simplification of the optical layout and the improved mechanical properties of the telescope and mount make of LOLAS-2 a more robust instrument.

Simultaneous generalized and low-layer SCIDAR turbulence profiles at san pedro mártir observatory

“…The LOLAS instrument operated with its dedicated 16-inch Ritchey-Chrétien telescope. LO-LAS data acquisition system and optical re-design was described by Avila et al (2016). The virtual distance d was set to 3000 m for the G-SCIDAR and 1100 m for LOLAS.…”

“…Instruments of G-SCIDAR and LOLAS methods have been developed at the Universidad Nacional Autónoma de México (UNAM) and reported in Cruz et al (2003) and Avilés et al (2012); Avila et al (2016), respectively. Here we report results obtained with these two instruments at the Observatorio Astronómico Nacional in San Pedro Mártir (OAN-SPM), Baja California, Mexico during three campaigns in 2013, 2014 and 2015.…”

Implementation of MUAV as reference source for GLAO systems

“…The second was done using the data of OAN acquired with the latest generation Low-Layer Scidar (LOLAS-2) instrument (Avila et al 2016), the same equations of atmospheric parameters were used and are in table 1 as LOLAS-2. For both analysis were considered a maximum height of the turbulent layer of h = 60 m, and an average wind speed for the first kilometer of height above the surface of the observatory of v = 2.3 m/s, reported by Cruz-Gonzales et al (2004).…”

Developing Fuzzy Inference System of the Observed Albireo Star’s Trail using Surface Meteorological Parameter over ITERA Astronomical Observatory (IAO)

“…As can be seen in Table 3, the three condition MFs FIS of Albireo (β Cyg) star seeing was applied in this study. The three condition MFs FIS of Albireo (β Cyg) star seeing based on turbulace over atmosphere [17,18]. The turbulence event over atmosphere are caused by climate area (cloud system) and surface meteorological parameter [19].…”