Moonlit Nights Research Articles

The expected characteristics of the Cherenkov telescope TAIGA-IACT equipped with SiPM detectors

Monte-Carlo modeling of effective area and count rate of the TAIGA-IACT Cherenkov gamma-ray telescope unit with an upgraded camera based on SiPM OnSemi MicroFJ-60035 detectors and optical filters SL 290-590 and SL 290-590 has been carried out. It has been shown that with the SL 290-590 filter the threshold detection energy of the telescope would be improved compared with its current PMT-based configuration and would reach about 0.4 TeV. With the narrow band UV filter SL 290-590 the estimated threshold would reach about 0.7 TeV, which is a reasonable value for a 10 m2 class IACT, especially because with a SiPM-based telescope it will be possible to carry out observations during moonlit nights and at twilight without a substantial increase of the threshold. One may conclude that an upgraded TAIGA-IACT unit will be an efficient instrument for studies of TeV-band gamma-ray emission of various cosmic objects.

Ferrocenyl Dinuclear Gold(I) Complexes. Study of their Structural Features and the Influence of Bridging and Phosphane Ligands in a Catalytic Cyclization Reaction.

Invited for the cover of this issue are the groups of Raquel P. Herrera and M. Concepción Gimeno at the Instituto de Síntesis Química y Catálisis Homogénea (University of Zaragoza-CSIC). The image depicts the light of the full moon illuminating a bridge between the gold(I) metal centers. Two dragons, symbolizing the use of bridging ligands, confront each other to determine the ultimate victor. Read the full text of the article at 10.1002/chem.202303585.

Sky subtraction of LAMOST at bright night

ABSTRACT Sky subtraction is a crucial step in the data reduction process for LAMOST, including dark, bright, and grey nights. During the pilot survey, on bright nights, atmospheric scattering of moonlight can introduce gradients in the sky background. In observations during bright moonlit nights, the sky component is significant, and sometimes, variations in colour can be observed in the sky spectra. This phenomenon is not universally present during observations on bright moonlit nights. Taking this into consideration, this paper proposes a weighted trend-surface method to reconstruct the sky component within the science target fibre, aiming to achieve the subtraction of the sky component. We constructed a sky model using a trend surface, utilizing data from all sky fibre spectra on the same spectrograph to predict the sky component for each fibre spectrum. Subsequently, the reconstructed sky spectrum data were compared with the actually observed sky spectrum data and the ‘super sky’ from LAMOST’s pipeline. The results indicate that our method is closer to the observed real sky spectrum than the ‘super sky’, showing smaller residuals and variance, with an average closer to zero. This method serves as a viable solution, particularly when dealing with colour variations observed during bright moonlit nights.

Intizar Hussain: The Master of Urdu-Hindi Civilization

Intizar Hussain was a fiction writer with a novel use of symbolic and metaphorical styles, but for all his retrospect and escapism and denial of the future, his writings have a strange poignancy and beauty. It has the same charm one feels in old buildings on moonlit nights. Besides being a respected name in Urdu fiction, he was a great challenge to the pioneer fiction writers due to his style and changing tones. The atmosphere of his writings echoes the stories of the past. Regret, rememberance of past , love of the classics, nostalgia for the past, lamenting the past and seeking refuge in tradition are very prominent here. In many places, the style and tone become harsh in expressing the sadness and expression of the disintegration of the old values ​​and the superficial and sentimental nature of the new values. He also made the mythological trend a part of his writings. Extensive study is also required to find out the mysteries of their legends. A special kind of tension regarding migration is ongoing with Intizar Hussain. He could not logically separate himself from this situation. He was not interested in the external structure of life, but he cared about the condition that was faced inwardly. This is the deep diving and stylistic diversity of Intar Hussain. But they also call it intellectual and visual backwardness. In such a case, they declare the moral struggle of the individual as meaningless. This thematic and stylistic level is where Intizar Hussain seems to enter the foreground of fiction.

Small mammals reduce activity during high moon illumination under risk of predation by introduced predators

Predation influences prey survival and drives evolution of anti-predator behaviour. Anti-predator strategies by prey are stimulated by direct encounters with predators, but also by exposure to indicators of risk such as moonlight illumination and vegetation cover. Many prey species will suffer increased risk on moonlit nights, but risk may be reduced by the presence of dense vegetation. Determining the role of vegetation in reducing perceived risk is important, especially given predictions of increased global wildfire, which consumes vegetation and increases predation. We used remote cameras in southeastern Australia to compare support for the predation risk and habitat-mediated predation risk hypotheses. We examined the influence of moonlight and understorey cover on seven 20–2500 g mammalian prey species and two introduced predators, red foxes and feral cats. Activity of all prey species reduced by 40–70% with increasing moonlight, while one species (bush rat) reduced activity in response to increasing moonlight more sharply in low compared to high understorey cover. Neither predator responded to moonlight. Our findings supported the predation risk hypothesis and provided limited support for the habitat-mediated predation risk hypothesis. For prey, perceived costs of increased predation risk on moonlit nights outweighed any benefits of a brighter foraging environment.

Study on a Low-Illumination Enhancement Method for Online Monitoring Images Considering Multiple-Exposure Image Sequence Fusion

In order to improve the problem of low image quality caused by insufficient illumination, a low-light image enhancement method with robustness is proposed, which can effectively handle extremely dark images while achieving good results for scenes with insufficient local illumination. First, we expose the images to different degrees to form a multi-exposure image sequence; then, we introduce global-based luminance weights and contrast-based gradient weights to fuse the multi-exposure image sequence; finally, we use a bootstrap filter to suppress the noise that may occur during the image processing. We employ pertinent assessment criteria, such as the Peak Signal to Noise Ratio (PSNR), Structural Similarity (SSIM), the Average Gradient (AG), and the Figure Definition (FD), to assess how well the method enhances. Experimental results show that PSNR (31.32) and SSIM (0.74) are the highest in pretty dark scenes compared to most conventional algorithms such as MF, BIMEF, LECARM, etc. Similarly, in processing uneven illumination such as “moonlit night” images, the AG (10.21) and the FD (14.54) are at maximum. In addition, other evaluation metrics such as Shannon (SH) are optimal in the above scenarios. In addition, we apply the algorithm in this paper to the online monitoring images of electric power equipment, which can improve the image lightness while recovering the detail information. The algorithm has strong robustness in extremely dark images and natural low-light images, and the enhanced images have minimal distortion and best appearance in different low-light scenes.

NSKY-CD: A System for Cloud Detection Based on Night Sky Brightness and Sky Temperature

Cloud cover is important meteorological information that still requires expensive equipment to be monitored from the ground, especially at night. The use of artificial lights at night causes light pollution, and clouds amplify this by reflecting light downward. In addition, cloud thermal radiation emissions affect sky temperature. In this study, we describe a system (NSKY-CD) that can be used to detect clouds at night since it integrates a sky quality meter that measures night sky brightness (NSB) and an air temperature and an infrared temperature sensor that measure sky temperature. We defined a cloud detection method based on fixed threshold values determined with two different procedures that we called ‘optimal’ and ‘antimode’. We then quantitatively assessed the performance of these methods in detecting the presence or absence of clouds in the urban area of Florence during two full moon cycles. Accuracy for the ‘optimal’ method varied between 87% and 91%, while for the ‘antimode’ method, it varied between 86% and 89%. Our results suggest that the two parameters are complementary since NSB has a better performance on moonless nights, and the difference between air temperature and sky temperature has a better performance on moonlit nights. Our method can also be used to analyze historical series of NSB to estimate cloud presence backwards, thus providing important information for meteorological, environmental and astronomical studies.

A study on the aesthetic characteristics of ethnic music based on radial basis neural network model

Abstract To explore the aesthetic features of folk music, this paper takes the radial basis neural network model as the basis and takes the zither piece “Flowing Water” and “Spring River Flower and Moonlight Night” as the examples, and unearths and analyzes the examples to understand the harmonious beauty, unique beauty and contextual beauty under the aesthetic characteristics. The results show that among the harmonious beauty, the average percentage of the characteristic vocabulary tranquility of the zither piece “Flowing Water” is 80.34% after learning by the radial-based neural network model, and the remaining percentages are 69.56%, 85.35%, 80.27% and 86.30% respectively, which shows that the radial-based neural network-based model can well resolve the characteristic vocabulary in the music through training and learning This shows that the radial basis neural network-based model can, through training and learning, well parse out the characteristic words in the music, and then explore the aesthetic features of the music. From the viewpoint of unique beauty, the musicalization of poetry and the poetization of music have been the main themes from ancient times to the present, with changes of 838% increase and 74.91% decrease, respectively, which also shows that the current degree of our attention to national music is not as much as that of the Tang, Song and Yuan dynasties, and we should strengthen the excavation of national music and create a unique humanistic environment. From the perspective of the beauty of the context, 67.81% of those who listened to “Spring River Moon Night Song” thought that the rhythm and context were full, and 79.48% thought that the theme melody and performance method were eye-catching, but there were still voices of dissatisfaction. Therefore, with the radial basis neural network model, we can intuitively see the aesthetic characteristics of folk music, and we can improve folk music according to its shortcomings so that folk music can be further renewed through a new interpretation.

The Effect of Light Pollution on the Sea Finding Behavior of Green Turtle Hatchlings on Lanyu Island, Taiwan.

octurnal animals use their vision and acute hearing to adapt to the nighttime environment. Light pollution has become a serious problem for nocturnal animals in coastal areas, especially nesting sea turtles and sea turtle hatchlings. Hatchlings use visual clues to find the ocean. However, when the artificial light is stronger than the natural light, hatchlings become either misoriented, disoriented or both. Due to rapid tourism development on Lanyu Island, new sources of light pollution, especially streetlights, pose a serious threat to sea turtle hatchlings. In this study, we used a portable lamp constructed by Liteon Inc. on a circular area of a turtle nesting beach to see how artificial light sources could affect green turtle hatchlings' sea finding behavior. In the experiments, we tested hatchling behavior under different lamp settings (strong or weak light intensity; white or yellow light; lamp shield presence or absence) and moon visibilities (moonlit or moonless). The hatchlings' crawling tracks and locations at the end of the trials were recorded. Results showed that the light intensity had no effect on hatchling sea finding behavior. White light had a stronger impact on hatchling sea finding behavior than yellow light. When the lamp shield was installed on moonlit nights, more hatchings were able to find the sea under both white and yellow lights. Thus, it is recommended that light shields be installed on the streetlights of Lanyu Island in order to protect the sea turtle hatchlings effectively.

The rhythm of the night: patterns of activity of the European wildcat in the Italian peninsula

The European wildcat is a threatened carnivore, whose ecology is still scarcely studied, especially in Mediterranean areas. In this study, we estimated activity rhythm patterns of this felid, by means of camera-trapping at three spatial scales: (i) whole country (Italy); (ii) biogeographical areas; (iii) latitudinal zones. The activity rhythms patterns were also calculated according to temporal scales: (1) warm semester; (2) cold semester and (3) seasonal scales. Lastly, we also tested whether the effect of moon phases affected the wildcat activity. We conducted the analysis on a total of 975 independent events collected in 2009–2021, from 285 locations, in ~ 65,800 camera days. We showed that the wildcat in Italy exhibits a > 70% nocturnal behaviour, with 20% of diurnal activity, at all spatial scales, and throughout the whole year, with peaks at 10.00 p.m. and 04.00 a.m. We observed a high overlap of wildcat activity rhythms between different biogeographical and latitudinal zones. The wildcat was mainly active on the darkest nights, reducing its activity in bright moonlight nights. Diurnal activity was greater in the warm months and decreased with the distance from shrubs and woodlands, most likely according to activity rhythms of its main prey, water presence in summer, the care of offspring and the availability of shelter sites. Conversely, the distance to paved roads seems to have no significant effects on diurnal activity, suggesting that, in presence of natural shelters, the wildcat probably may tolerate these infrastructures. We suggested limited plasticity in activity rhythm patterns of the wildcat, emphasizing the importance of dark hours for this species.

Moonlight drives nocturnal vertical flight dynamics in black swifts

Many animals have evolved a migratory lifestyle as an adaptation to seasonality,1,2 ranging from insects3 to fish,4 terrestrial and marine mammals,5-7 and birds.8 Old World swifts have evolved an extraordinary aerial non-breeding life phase lasting for 6-10 months.9-11 Swifts exploit the aerosphere in search of insects to meet the high energy demands of flight.12 During this period they roost and likely also sleep in the open airspace. Nocturnal insectivores with restricted foraging time may use moonlight to increase energy intake.13 Using multisensor data loggers that record light for geolocation, acceleration for flight activity, and pressure for flight altitude, we investigated if Northern black swifts, Cypseloides niger borealis, breeding in North America, also lead an aerial lifestyle similar to their Old World relatives. Individual flight activity showed they are airborne >99% of the time, with only occasional landings during their 8-month non-breeding period. Unexpectedly, during periods around the full moon, they conducted regular nocturnal ascents to altitudes up to >4,000 m (mean 2,000 m). A lunar eclipse triggered a synchronized descent, showing a direct effect of moonlight on flight altitude. This previously unknown behavior of nocturnal ascents during moonlight nights could be either a response to predator avoidance or that moonlight provides a foraging opportunity. Observed elevated nocturnal flight activity during periods of moonlight compared to dark nights suggests swifts were hawking for prey. Our finding of this novel behavior provides new perspectives on nocturnal flight behavior during periods surrounding the full moon.

Temporal Partitioning between Forest-Dwelling Small Rodents in a Mediterranean Deciduous Woodland.

Simple SummaryCamera-trapping has been widely used to assess activity rhythms and temporal overlap of different medium- and large-sized mammal species sharing the same habitats. Conversely, this method has been poorly applied to small mammals, which are often difficult to identify at the species level through photos. In our work, we assessed the temporal overlap between two coexisting small rodents in forest environments, Apodemus flavicollis and Clethrionomys glareolus. We collected 124 independent records of A. flavicollis and 67 records of C. glareolus over three years. The former was mostly nocturnal, with activity peaking after midnight, whereas the latter was mostly active at dawn and dusk. In other words, we recorded a limited temporal overlap, thus suggesting a potential for interspecific competition. Intraguild interference competition between A. flavicollis and C. glareolus may play a pivotal role, forcing C. glareolus to be more active in daylight hours, when the more strictly nocturnal A. flavicollis is present. Nocturnal activity of C. glareolus was limited and not influenced by moon phases, whereas A. flavicollis was mostly active in the darkest nights, avoiding bright moonlight nights.Temporal partitioning is reported as one of the main strategies adopted by coexisting mammal species to limit interspecific competition and behavioural interference. In the last decades, camera-trapping surveys have provided valuable insights in assessing temporal niche and activity rhythms of medium and large-sized mammalian species. Conversely, this method has been poorly applied to small rodents. In this work we aimed at assessing temporal niche partitioning between two species of forest-dwelling small rodents—Apodemus flavicollis and Clethrionomys glareolus—by means of intensive camera-trapping. Camera traps were placed in areas where previous genetic analyses have confirmed the only presence of A. flavicollis amongst wood mice species, to prevent misinterpretation of records. We collected 124 independent records of A. flavicollis and 67 records of C. glareolus over three years. The former was mostly nocturnal, with activity peaking after midnight, whereas the latter was mostly active at dawn and dusk. Therefore, a limited temporal overlap was observed, confirming the potential for interspecific competition. Intraguild interference competition between A. flavicollis and C. glareolus may play a pivotal role forcing C. glareolus to be more active in daylight hours where, the more strictly nocturnal A. flavicollis is present. Nocturnal activity of C. glareolus was limited and not influenced by moon phases, whereas A. flavicollis was mostly active in the darkest nights, avoiding bright moonlight nights.

Estimation of optimal wavelengths for atmospheric non-line-of-sight optical communication in the UV range of the spectrum in daytime and at night for baseline distances from 50 m to 50 km.

For implementation of non-line-of-sight optical communication, the wavelength from the range 200-400 nm at which the signal-to-noise ratio reaches a maximum depending on the baseline distance is estimated. The estimates are performed in the daytime, at moonlit night, and without background radiation. The results obtained allow us to recommend λ=290nm for the implementation of the long-range communication in the daytime and λ=350nm at night. For impulse response that provides the basis for estimating the communication channel quality, four algorithms of the Monte Carlo method are considered. The algorithm with modified double local estimate provides the least error for the same number of photon trajectories. UV radiation is potentially dangerous to humans, and therefore, the illuminance of the Earth's surface is estimated under the optical axis of the source for baseline distances of 2, 10, and 100 m together with the time period of a continuous communication session safe for operators.

Monitoring vocal activity and temporal patterns in attendance of White-chinned Petrels using bioacoustics

ABSTRACT Monitoring of population sizes and trends using conventional surveys is challenging for nocturnal, burrow-nesting seabirds. The White-chinned Petrel is the most commonly killed species in Southern Ocean fisheries and its breeding success at many sites is reduced because of predation by invasive cats and rodents. As adaptive management of such threats requires cost-effective and reproducible protocols for monitoring populations, we examined the potential of automated bioacoustic techniques for measuring colony attendance patterns (relative number of birds visiting at a given time) using data from acoustic recorders deployed over a breeding season at Bird Island, South Georgia. Generic recognition software was of limited utility, but a suite of acoustic indices in a random forest model reliably predicted the occurrence of vocalisations. Vocal activity showed clear temporal patterns, despite high day-to-day variability, and was lowest during the pre-laying period, in the early evening, and on moonlit nights. To facilitate estimation of population density using acoustic recorders, we determined the mean vocalisation rate of individuals (2.3 min−1), mean call length (~15.3 sec), and detection distance (~15 m based on signal to noise ratios of playbacks). Our results indicate that acoustic indices are a useful measure of colony attendance. If these indices can be linked to density, acoustic monitoring would provide a powerful and cost-effective census method for White-chinned Petrels and other nocturnal species.

Carried away by a moonlight shadow: activity of wild boar in relation to nocturnal light intensity

An increase of nocturnal activity of ungulate species may represent a compensatory opportunity for energy intake, when activity in daylight is hindered by some disturbance events (e.g. hunting or predation). Therefore, mostly-diurnal and crepuscular species may be active in bright moonlight nights whereas others may shift their diurnal activity towards darkest nights to limit their exposure to predators. In natural and undisturbed conditions, the wild boar may be active both during the day and the night, with alternating periods of activity and resting. In this work, we tested whether activity patterns of wild boar, a species with poor visive abilities, were dependent on moon phases and environmental lightening. We aimed to assess if nocturnal activity could be better explained by variations of the lunar cycle or by the variations of environmental lightening conditions, evaluated by means of different measures of night brightness. Data were collected through camera-trapping in Central Italy in 2019–2020. Despite the poor visive abilities of the wild boar, we observed that this ungulate significantly reduced their activity by avoiding the brightest nights. In our study area, the wild boar has to cope with both human pressure (i.e. mostly hunters and poachers) and predation by the grey wolf. Furthermore, the nocturnal activity of wild boar peaked in mid-Autumn, i.e. when hunting pressure is the highest and when leaf fall may bring wild boar to range for long distances to find suitable resting sites for diurnal hours.

Didactic and pedagogical dimensions of Igbo oral children’s songs

Abstract There is a sharp decline in the performance of Igbo oral songs by children in recent times. Unlike in the days gone, children of nowadays rarely gather in groups in the evenings or during moonlight nights to play and perform some dramatic and musical renditions which are informal forms of education. Parents now encourage their children to watch home-movies and some channel programmes in the comfort of their homes; they encourage them to embark more on some in-door games while advancing security reasons as the basis for not allowing them to participate in various forms of open communal recreation. Such attitude deprives children of the essential moralistic and educational values expected to be imbibed from the rendition of native songs in playful groups. This paper which is based on a fieldwork carried out in 2018 in Umuawuchi, an Igbo community in Imo State Nigeria, investigates the instructional values of Igbo oral children’s songs. Reiterating the moral-imparting attributes of Igbo children’s songs, the paper applies Performance Theory to investigate the thematic standpoints of Igbo children’s songs while gauging the extent to which they can be applied to impart and extrapolate on key moral values of the Igbo. The paper restates certain measures that can be activated to incorporate children’s songs into mainstream educational and mass-communication media to avert the complete loss of such rich literary repertoires.

VOCAL ACTIVITY OF THE GREAT POTOO (NYCTIBIUS GRANDIS) IN RELATION TO MOONLIGHT: DETECTIONS IN COSTA RICA

Variations in moonlight can affect the vocal activity of many nocturnal birds, including the Great Potoo (Nyctibius grandis), a rarely seen bird usually detected through its characteristic calls. We evaluated the vocal activity of the Great Potoo in relation to moonlight in a Tropical Forest of Costa Rica. We surveyed potoos using four replicated 13-minute counts covering a single moon cycle at 31 points at La Selva Biological Station during March and April 2020. We detected seven Great Potoos on nights with 76-100% moonlight, three on nights with 51-75% moonlight, and none on nights with 0-50% moonlight. Great Potoos were more easily detected during moonlit nights, which is consistent with other studies of ‘lunarphilic’ nocturnal birds, and suggests that future studies modeling occupancy or habitat use of Great Potoos should consider moonlight as a covariate of detectability.

Segmenting Star Images with Complex Backgrounds Based on Correlation between Objects and 1D Gaussian Morphology

Space object recognition in high Earth orbits (between 2000 km and 36,000 km) is affected by moonlight and clouds, resulting in some bright or saturated image areas and uneven image backgrounds. It is difficult to separate dim objects from complex backgrounds with gray thresholding methods alone. In this paper, we present a segmentation method of star images with complex backgrounds based on correlation between space objects and one-dimensional (1D) Gaussian morphology, and the focus is shifted from gray thresholding to correlation thresholding. We build 1D Gaussian functions with five consecutive column data of an image as a group based on minimum mean square error rules, and the correlation coefficients between the column data and functions are used to extract objects and stars. Then, lateral correlation is repeated around the identified objects and stars to ensure their complete outlines, and false alarms are removed by setting two values, the standard deviation and the ratio of mean square error and variance. We analyze the selection process of each thresholding, and experimental results demonstrate that our proposed correlation segmentation method has obvious advantages in complex backgrounds, which is attractive for object detection and tracking on a cloudy and bright moonlit night.

Nocturnal foraging lifts time constraints in winter for migratory geese but hardly speeds up fueling.

Climate warming advances the optimal timing of breeding for many animals. For migrants to start breeding earlier, a concurrent advancement of migration is required, including premigratory fueling of energy reserves. We investigate whether barnacle geese are time constrained during premigratory fueling and whether there is potential to advance or shorten the fueling period to allow an earlier migratory departure. We equipped barnacle geese with GPS trackers and accelerometers to remotely record birds’ behavior, from which we calculated time budgets. We examined how time spent foraging was affected by the available time (during daylight and moonlit nights) and thermoregulation costs. We used an energetic model to assess onset and rates of fueling and whether geese can further advance fueling by extending foraging time. We show that, during winter, when facing higher thermoregulation costs, geese consistently foraged at night, especially during moonlit nights, in order to balance their energy budgets. In spring, birds made use of the increasing day length and gained body stores by foraging longer during the day, but birds stopped foraging extensively during the night. Our model indicates that, by continuing nighttime foraging throughout spring, geese may have some leeway to advance and increase fueling rate, potentially reaching departure body mass 4 days earlier. In light of rapid climatic changes on the breeding grounds, whether this advancement can be realized and whether it will be sufficient to prevent phenological mismatches remains to be determined.

Bioinspired polarized light compass in moonlit sky for heading determination based on probability density estimation

Bioinspired polarized skylight navigation, which can be used in unfamiliar territories, is an important alternative autonomous navigation technique in the absence of Global Navigation Satellite System (GNSS). However, the polarization pattern in night environment with noise effects and model uncertainties is a less explored area. Although several decades have passed since the first publication about the polarization of the moonlit night sky, the usefulness of nocturnal polarization navigation is only sporadic in previous researches. This study demonstrates that the nocturnal polarized light is capable of providing accurate and stable navigation information in dim light outdoor environment. Based on the statistical characteristics of Angle of Polarization (AoP) error, a probability density estimation method is proposed for heading determination. To illustrate the application potentials, the simulation and outdoor experiments are performed. Resultingly, the proposed method robustly models the distribution of AoP error and gives accurate heading estimation evaluated by Standard Deviation (STD) which is 0.32° in a clear night sky and 0.47° in a cloudy night sky.