Study on Atmospheric Optical Turbulence above Mount Shatdzhatmaz in 2007–2013

Abstract

We present the results of the atmospheric optical turbulence (OT) measurements performed atop Mt. Shatdzhatmaz at the installation site of new 2.5-m telescope of Sternberg Astronomical Institute. Nearly 300 000 vertical OT profiles from the ground up to an altitude of 23 km were obtained in the period with the combined multi-aperture scintillation sensor (MASS) and differential image motion monitor (DIMM) instrument.The medians of the main OT characteristics computed over the whole dataset are as follows: the integral seeing β 0 = 0.96 arcsec, the free-atmosphere seeing β f ree = 0.43 arcsec, and the isoplanatic angle θ 0 = 2.07 arcsec. The median atmospheric time constant is τ 0 = 6.57 ms. The revealed long-term variability of these parameters on scales of months and years implies the need to take it into account in astroclimatic campaign planning. For example, the annual variation in the monthly θ 0 estimate amounts up to 30% while the time constant τ 0 changes by a factor of 2.5.Evaluation of the potential of Mt. Shatdzhatmaz in terms of high angular resolution observations indicates that in October-November, this site is as good as the best of studied summits in the world.

Astronomical observation tasks short-term scheduling using PDDS algorithm

“…An input for the environment models is supposed to be obtained online using dedicated monitoring experiments, for instance, the capable automatic seeing monitor has been running on the site of the SAI MSU 2.5 m telescope for eight years. [9]. This way, the optimisation problems are to be solved a number of times per night using actual current initial state.…”

Apparent motion of the circumstellar envelope of CQ Tau in scattered light

“…The observations were made using SPeckle Polarimeter (SPP), which is a dual-beam polarimeter and speckle camera equipped with an Electron Multiplying CCD (EMCCD) sensor Andor iXon 897. The instrument is installed at the 2.5-m telescope of Caucasian Mountain Observatory of Sternberg Astronomical Institute of Lomonosov Moscow State University (Kornilov et al 2014). Splitting of the orthogonally polarized beams is done by a Wollaston prism, both images formed by the latter are located side-by-side on the same detector, see Fig.…”

Forecasting seeing and parameters of long-exposure images by means of ARIMA

“…The notation in expressions (12) and (11) corresponds to that it expression (10). Further, for the sake of simplicity, γ 3 without an argument denotes just γ 3 (0.8).…”

“…It is important to note that the quantities being summed are not correlated in the earlier paper [6], but our quantities are correlated. Moreover, equations (12) and (11) have the form of the sum of the log-normally distributed quantities only when Taylor series decomposition has been applied in the following way:…”

“…The partial derivatives of γ 2,3 are calculated with respect to the implicit function theorem and using equations (11) and (12). The mean and the covariance of the log-normally distributed quantities i are exactly given by expressions (15) and (16).…”