The Silesian University of Technology Observatories (SUTO) group's solar patrol station, SUTO Solar, is designed to collect patrol images of the Sun. The observatory is operated remotely and equipped with a 60-mm Lunt telescope for imaging in the Ha 656.28 nm hydrogen line and an 80-mm SkyWatcher refractor for imaging in the continuum centered at 540 nm. Both telescopes use complementary metal-oxide-semiconductor (CMOS) cameras. A set of environmental sensors measuring temperature, humidity, and pressure provide information about the optical instruments. Real-time full-disk images and archival data are shared via a dedicated web page. In future work, low-resolution images generated by SUTO Solar will be used as training datasets for dedicated machine learning algorithms designed to enhance images acquired by small instruments. (c) 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)

NASA’s Transiting Exoplanet Survey Satellite (TESS) mission promises to improve our understanding of hot Jupiters by providing an all-sky, magnitude-limited sample of transiting hot Jupiters suitable for population studies. Assembling such a sample requires confirming hundreds of planet candidates with additional follow-up observations. Here we present 20 hot Jupiters that were detected using TESS data and confirmed to be planets through photometric, spectroscopic, and imaging observations coordinated by the TESS Follow-up Observing Program. These 20 planets have orbital periods shorter than 7 days and orbit relatively bright FGK stars (10.9 < G < 13.0). Most of the planets are comparable in mass to Jupiter, although there are four planets with masses less than that of Saturn. TOI-3976b, the longest-period planet in our sample ( P = 6.6 days), may be on a moderately eccentric orbit ( e = 0.18 ± 0.06), while observations of the other targets are consistent with them being on circular orbits. We measured the projected stellar obliquity of TOI-1937A b, a hot Jupiter on a 22.4 hr orbit with the Rossiter–McLaughlin effect, finding the planet’s orbit to be well aligned with the stellar spin axis (∣ λ ∣ = 4.°0 ± 3.°5). We also investigated the possibility that TOI-1937 is a member of the NGC 2516 open cluster but ultimately found the evidence for cluster membership to be ambiguous. These objects are part of a larger effort to build a complete sample of hot Jupiters to be used for future demographic and detailed characterization work.

Imaging through turbulence has been the subject of many research papers in a variety of fields, including defence, astronomy, earth observations, and medicine. The main goal of such research is usually to recover the original, undisturbed image, in which the impact of spatially dependent blurring induced by the phase modulation of the light wavefront is removed. The number of turbulence-disturbed image databases available online is small, and the datasets usually contain repeating types of ground objects (cars, buildings, ships, chessboard patterns). In this article, we present a database of solar images in widely varying turbulence conditions obtained from the SUTO-Solar patrol station recorded over a period of more than a year. The dataset contains image sequences of distinctive yet randomly selected fragments of the solar chromosphere and photosphere. Reference images have been provided with the data using computationally intensive image recovery with the latest multiframe blind deconvolution technique, which is widely accepted in solar imaging. The presented dataset will be extended in the next few years as new image sequences are routinely acquired each sunny day at the SUTO-Solar station.

Abstract. Here, we describe an implementation of an electron-multiplying charge-coupled device camera to search for seismological activity in white dwarfs (WD). The equipment was installed on the 2.12-m telescope at the Observatorio Astronómico Nacional San Pedro Mártir, Baja California, México. We have determined the proper operational regime to keep a very low noise while maintaining a high gain. We have also developed software for the instrument control system and data processing. Finally, we report the first results on the seismological activity of WD, obtained using photometry with one-second exposure. The results were compared to the known variables LAMOST J004628.31 + 343319.90 and GD 66. The WD 2255-001 showed very weak periodic activity with a dominant frequency of 67 mHz.

We present our first results of multiband Speckle Holography of components of visual double stars. The observations were performed during 2019 April at the 2.1 m telescope at the Observatorio Astronomico Nacional at Sierra de San Pedro Martir (Mexico). We have observed 190 double stars with separation between 3 '' and 5 ''. The position angle, separation and magnitude difference in three broadband optical filters (VRI) for these systems are provided. For 15 systems we found different interesting features, we have identified a close component for 9 of those systems; 5 of them are newly discovered. In the remaining 6 systems, although unresolved, we found elongations that we have been able to derive astrometric parameters if proven to be a (newly discovered) close component. This corresponds to about 8% of the sample presenting a certain feature in one of the components and about 5% of the sample having a confirmed close component.

This paper presents the conceptual design for a new method for the suppression of OH emission lines at near-infrared (NIR) wavelengths by actively adjusting the aperiodic fiber optic Bragg gratings tension. First, we prepared an experimental study in which we simulated an OH emission line using a semiconductor laser at 1548.43 nm and a commercial FBG, with a Bragg wavelength of 1547.76 nm. We demonstrated that the grating Bragg wavelength can be adjusted by controlling the linear deformation of the fiber with a force in the range of 0 to 53.88 gf (0.528 N) that provides a sensitivity of 0.014 nm g −1 . Second, we proposed the design of a system connected to the telescope instrumentation, with the different stages that would allow monitoring the suppression of emission lines.

A fast photometry methodology is described. We use a cooled Ixon Ultra emCCD in photon counter mode to acquire data. A dissipation system is added to stabilize the temperature down to -96 C. The sensibility of this system makes it ideal even for small telescopes.

A Monte Carlo method implemented in the PRIZMA-DSP code to calculate multiplying systems, including weakly coupled systems, is described. In the code, the basis of the method is a sequential calculation of a prescribed chain of active generations, which is described by, first and foremost, the dominant ratio of the system. The fission points of the running generation serve as a source for constructing neutron trajectories, new fission points arising on a trajectory are transmitted unchanged to calculate the next generation, and so on. In the calculation of the active generation, Keff and made-to-order linear-fractional functions are evaluated. In order for the distribution to become established, a passive calculation with prescribed chain length is made before the active calculation. In addition, after the calculation of each generation the operation of random mixing of the entire set of fission points and their distribution over the nuclei is performed in order to obtain a uniform distribution. At the start of the calculation, a special rejection procedure performs a pre-set number of preliminary computational iterations so that an arbitrary zeroth distribution over all nuclei goes to a distribution obtained via a characteristic function.

We present speckle interferometric measurements of binary stars performed during 2011 February and April with the 1.5-m telescope and during 2011 July and November with the 2.1-m telescope of the Observatorio Astronomico Nacional, San Pedro Martir, Mexico, focusing on objects from the Washington Double Star Catalog with separations less than 1 arcsec. Among these objects, we have been interested in performing a follow-up observation of new double stars discovered by Hipparcos. For these observations, we developed a new detector, which is a combination of CCD Watec 120N with a third generation image intensifier. This image intensifier allows us to perform near-infrared speckle interferometric observations for the first time. In this paper, we report 761 astrometric measurements of 478 pairs, with angular separations ranging from 0.09 to 2.61 arcsec. We found that 722 of our measured separations are smaller than 1 arcsec. We estimated a mean error in separation of 16 mas and 1.29 degrees in position angle. In order to overcome the usual 180 degrees ambiguity inherent to speckle measurements, we created a shift-and-add reconstructed image of each source, to establish the true quadrant of the secondary star. We confirmed 40 double stars discovered by Hipparcos and found 4 field stars resolved as interferometric pairs for the first time, with separations smaller than 0.60 arcsec.

The resolution of astronomical images taken from the ground is severely degraded by the atmosphere. One of the simplest methods for overcoming this problem is tip-tilt (TT) correction. This method is especially valuable for small telescopes, as it enables them to reach their diffraction limit. Unfortunately, the method requires a bright guide star to asses the blurring of astronomical images. In this study we show how various factors influence the feasibility of tip-tilt correction in very small telescopes (<= 1 m). We evaluate the effect of: (1) the intensity of the guide star, (2) seeing conditions, (3) telescope size and (4) sky background. The results are obtained from data simulated using the Random Wave Vector method. The dependencies presented in this paper can be used to predict the sky coverage of small telescopes with TT correction for a wide range of observational conditions.

Observations of the solar photosphere from the ground encounter significant problems caused by Earth’s turbulent atmosphere. Before image reconstruction techniques can be applied, the frames obtained in the most favorable atmospheric conditions (the so-called lucky frames) have to be carefully selected. However, estimating the quality of images containing complex photospheric structures is not a trivial task, and the standard routines applied in nighttime lucky imaging observations are not applicable. In this paper we evaluate 36 methods dedicated to the assessment of image quality, which were presented in the literature over the past 40 years. We compare their effectiveness on simulated solar observations of both active regions and granulation patches, using reference data obtained by the Solar Optical Telescope on the Hinode satellite. To create images that are affected by a known degree of atmospheric degradation, we employed the random wave vector method, which faithfully models all the seeing characteristics. The results provide useful information about the method performances, depending on the average seeing conditions expressed by the ratio of the telescope’s aperture to the Fried parameter, D/r_0 . The comparison identifies three methods for consideration by observers: Helmli and Scherer’s mean, the median filter gradient similarity, and the discrete cosine transform energy ratio. While the first method requires less computational effort and can be used effectively in virtually any atmospheric conditions, the second method shows its superiority at good seeing ( D/r_0<4 ). The third method should mainly be considered for the post-processing of strongly blurred images.

ABSTRACT Karhunen–Loeve functions for the case of non-Kolmogorov turbulence are calculated. The calculations are performed using the covariance matrix of Zernike coefficients which is derived in analytical form. It is shown that the Karhunen–Loeve expansion is more efficient than the Zernike one for simulations of high-order, turbulence-induced phase distortions.

Temporal properties of Zernike modes are investigated for the case of light wave propagation through the non-Kolmogorov turbulence. The calculations are performed for the weak-turbulence conditions with constant turbulence parameters along the propagation path and taking into account the effects of the outer and inner scale of the turbulence. It is shown that the difference between effects produced by the Kolmogorov and non-Kolmogorov turbulence is getting smaller when the aberration order is growing up and when the outer scale magnitude is decreasing. Also it is shown that the correlation time of an aberration is decreasing with increasing of its order and with decreasing of spectral index.

The impulsive noise in astronomical images originates from various sources. It develops as a result of thermal generation in pixels, collision of cosmic rays with image sensor or may be induced by high readout voltage in Electron Multiplying CCD (EMCCD). It is usually efficiently removed by employing the dark frames or by averaging several exposures. Unfortunately, there are some circumstances, when either the observed objects or positions of impulsive pixels evolve and therefore each obtained image has to be filtered independently. In this article we present an overview of impulsive noise filtering methods and compare their efficiency for the purpose of astronomical image enhancement. The employed set of noise templates consists of dark frames obtained from CCD and EMCCD cameras working on ground and in space. The experiments conducted on synthetic and real images, allowed for drawing numerous conclusions about the usefulness of several filtering methods for various: (1) widths of stellar profiles, (2) signal to noise ratios, (3) noise distributions and (4) applied imaging techniques. The results of presented evaluation are especially valuable for selection of the most efficient filtering schema in astronomical image processing pipelines.

The potential efficiency of shift-and-add (SAA) real-time correction is investigated. The study is performed using the data obtained with a 2.1-m telescope. The experimental data consist of sets of star images obtained with a high-speed CCD camera. The observations were performed during seven nights; 26 total sets of data were gathered, each containing 10,000 frames captured with a speed of 200 frames s-1. The data reduction allows us to estimate the temporal efficiency of SAA real-time correction in dependance of correction speed. Analyzing the results obtained, one can conclude that, on average, the SAA correction can be quite efficient even under a quite low correction speed (30–50 Hz). Because these results were obtained for a visible range (V band), another, maybe more interesting conclusion can be made: SAA real-time correction can work in the visible range where conventional adaptive systems have quite low efficiency.

We present a high-angular resolution survey for the search of binary and multiple stars in the Galactic open cluster Melotte 111. Combining our own speckle-interferometric observations with data taken from the literature, we found a ratio of the number of single to multiple stars to be 29:8: 0:0:0:1 for the most probable members, indicating a multiplicity fraction for this cluster of 25.6% +/- 2%. We also observed field stars in the vicinity of the cluster and estimated a ratio of multiplicities of 286:17:1:0:0:0:1 (between one and seven companions), equivalent to a multiplicity fraction of 5.9% +/- 3%. We showed that the cumulative distribution of separations for our sample stars is in agreement with Opik's law.

V. G. Orlov and V. V. VoitsekhovichInstituto de Astronom´ia, Universidad Nacional Autonoma de M´exico, M´exico D. F., M´exicoReceived July 27 2015; accepted July 30 2015In the paper entitled: SPECKLE INTERFEROMETRY AT THE OBSERVATORIO ASTRONOMICO´NACIONAL. VI. by V. G. Orlov and V. V. Voitsekhovich, that was published in RMxAA, Vol. 51, No. 1, pp.65-72, April 2015, there is an error. Page 68, Table 2, Line 66, String 62.It is written: 17075 + 3810 COU1291 0.3423 302.1 1.9 0.27 0.02 -30.59 0.06 (Docobo u0026 Ling 2011a)It should be: 17075 + 3810 COU1291 0.3423 302.1 1.9 0.27 0.02 -0.98 -0.01 (Docobo u0026 Ling 2011a)265

We present a new observational speckle interferometric study of stars with parallaxes larger than 200 milliarc-second (mas) from the Tycho Main Catalogue. According to this catalogue, there are more than 5000 objects meeting this criterion. Relatively small telescopes can be effectively used for this purpose since they can reach the Rayleigh resolution limit R = 1.22 lambda/D. For instance, the resolution of a 2m telescope in the V band is 0.055 ''. For 5 pc that corresponds to 0.275 au. In July 2014 we began speckle observations of stars with large parallaxes from the Tycho Main Catalogue.

The goal of the present study is the development and testing of a method for spectral detection of the light of host stars reflected from their exoplanets. The presented method is based on the analysis of dynamical spectra, which make it possible to obtain high signal-to-noise residual spectra after host star spectrum deduction. These residual spectra contain information on the light reflected from an exoplanet and on its albedo. The first results of such research for the exoplanet HD 189733b are presented in the paper. We obtained a series of a few dozens moderate-resolution spectra of the host star HD 189733. Individual spectra have a high signal-to-noise ratio (≈700) and cover a considerable part of the complete orbital cycle of the exoplanet. The use of the developed method allowed us to achieve a characteristic contrast of the reflected light detection at a level of 5 × 10 −4 from the continuum. Investigation of the dynamic spectra with this characteristic value as a detection threshold has not revealed obvious evidence of the host star light reflected from the planet. Nevertheless, the obtained threshold is high, which demonstrates the necessity of the development of the method for the exoplanet monitoring studies.