The Moon apparently seems to have not appreciable effect in the geomagnetic monthly period, but Keil (1839), Sabine (1853), Broun (1874) and many others have shown a lunisolar daily variation. It is known that solar (S) and lunar (L) variation have seasonal variations. Seasonal changes of S, particularly on quiet days, have been studied in greater detail than the seasonal changes for L. The purpose of this paper is to describe in more detail the effect of the variation of L in the geomagnetic equator, in the absence of strong perturbations selecting conveniently geomagnetic data of Huancayo observatory (hourly mean) from January 1, 2008 to December 31, 2009, period which is longer in range of minimum solar activity of the last 160 years (end of solar cycle 23 and start of solar cycle 24). The spectral analysis by wavelet and Fourier allows us to identify the main contribution of S diurnal and semidiurnal variations and its sidebands, besides the effect of the seasonal variation. In order to observe the variation L is subtracted the variation S together with its sidebands, allowing observed by Fourier spectral analysis and wavelet as the main contributions to the variation L, similar effect were described by Chapman and Miller (1940).

On September, 15th, 2007, in the community of Carancas (Puno, Peru) a stony meteorite formed a crater explosive type with a mean diameter of 13.5 m. some samples meteorite fragments were collected. The petrologic analysis performed corresponds to a meteorite ordinary chondrite H 4-5. In this paper we have analyzed the magnetic properties of a meteorite fragment with a proton magnetometer. Also in order to have a complete characterization of the Carancas meteorite and its crater, from several papers, articles and reports, we have made a compilation of the most important characteristics and properties of this meteorite.

The effect of solar flare, sudden commencement of magnetic storm and of the disturbances ring current on the equatorial electrojet in the Eastern Brazil region, where the ground magnetic declination is as large as \(20^{^{\circ }}\hbox {W}\) is studied based on geomagnetic data with one minute resolution from Bacabal during November–December 1990. It is shown that the mean diurnal vector of the horizontal field was aligned along \(2{^{\circ }}\hbox {E}\) of north at Huancayo and \(30{^{\circ }}\hbox {W}\) of north at Bacabal during the month of December 1990. Number of solar flares that occurred on 30 December 1990 indicated the direction of solar flare related \(\Delta H\) vector to be aligned along \(5{^{\circ }}\hbox {E}\) of north at Huancayo and \(28{^{\circ }}\hbox {W}\) of north at Bacabal. This is expected as the solar flare effects are due to the enhanced conductivity in the ionosphere. The SC at 2230 UT on 26 November 1990 produced a positive impulse in \(\Delta X\) and negative impulse in \(\Delta Y\) at Bacabal with \(\Delta H\) vector aligned along \(27{^{\circ }}\hbox {W}\) of north. At Huancayo the \(\Delta H\) vector associated with SC is aligned along \(8{^{\circ }}\hbox {E}\) of north, few degrees east to the alignment of the diurnal vector of H. The magnetic storm that followed the SC had a minimum Dst index of –150 nT. The corresponding storm time disturbance in \(\Delta X\) at Huancayo as well as at Bacabal were about –250 nT but \(\Delta Y\) at Bacabal was about +70 nT and very small at Huancayo, that give the alignment of the H vector due to ring current about \(16{^{\circ }}\hbox {W}\) of north at Bacabal and almost along N–S at Huancayo. Thus alignment of the \(\Delta H\) vector due to ring current at Bacabal is \(14{^{\circ }}\hbox {E}\) of the mean direction of \(\Delta H\) vector during December 1990. This is consistent with the direction of ring current dependent on the dipole declination at the ring current altitude which is about \(5{^{\circ }}\hbox {W}\) of north over Bacabal and the deviation of declination due to the ring current during disturbed period given by the angle (\(\psi \)-D).

The Calbuco volcano in southern Chile erupted on April 22, 2015. About 2 h after the first eruption, a Swarm satellite passed above the volcano and observed enhancement of small-amplitude (~0.5 nT) magnetic fluctuations with wave-packet structure which extends 15° in latitude. Similar wave packet is seen at the geomagnetic conjugate point of the volcano. Just after the eruption, geomagnetic fluctuations with the spectral peaks around the vertical acoustic resonance periods, 215 and 260 s, were also observed at Huancayo Geomagnetic Observatory located on the magnetic equator. Besides these observations, around 4-min, i.e., 175, 205 and 260 s, oscillations of total electron content (TEC) were observed at global positioning system stations near the volcano. The horizontal propagation velocity and the spatial scale of the TEC oscillation are estimated to be 720 m/s and 1600 km, respectively. These observations strongly suggest that the atmospheric waves induced by explosive volcanic eruption generate TEC variation and electric currents. The Swarm observation may be explained as a manifestation of their magnetic effects observed in the topside ionosphere.

Wavelet spectral analysis is applied to the daily indices K (SK) registered in Huancayo geomagnetic observatory from 2000.0 to 2015.0, it has become possible to identify predominant periodic components with a confidence level of 95 13.5, 9.0 and 6.8 harmonics, related to the fundamental period of solar rotation effects. A special analysis registered on periods of 59.0 days might be related to the double period of 29.53 days corresponding to the synodic month. The manifestation of the periods of 182.6, 365 and 730 days corresponding to the harmonics of the seasonal variation of the annual cycle is also observed. An important observation is that the global predominant periods registered 6.8 and 9.0 days, in the years 2009, 2013 and 2014 its effect is too small or null, those periods corresponds to the minimum and maximum solar activity. On the other hand, it is observed that the order of predominance of the harmonic period solar rotation are different for each solar cycle (Solar Cycle 23: 9.0, 13.5, 27.0 and 6.8 days; solar cycle 24: 27.0, 13.5, 9.0 and 6.8 days), and it is weaker contribution in the solar cycle 24 with respect to the solar cycle 23.

In this article we study the seasonal effect on the diurnal variation of the geomagnetic field registered in the Huancayo Observatory, located in the Magnetic Equator, which is driven by "ionospheric currents" and its counterpart induced by "telluric currents". Huancayo Observatory has the highest amplitude in the diurnal variation, because of being in the Magnetic Equator and under the "Equatorial Electrojet". We present the pattern of seasonal variation in diurnal variation of components X, Y and Z, the same as confirmed by previous works since 1940. The effect of solar activity cycle of about 11 years in the diurnal variation is also confirmed; it is observed that amplitudes are greater in the maximum of solar activity.

The Chapman-Miller method is used for analysis of lunar daily variations in geomagnetic and atmospheric pressure data recorded in Huancayo Observatory. Hourly mean data were used for the years 2008 and 2009, because it corresponds to the period of minimum solar and geomagnetic activity. A marked Lunar semidiurnal contribution is observed in the horizontal component H of the geomagnetic field, also the contribution is observed in the others lunar semidiurnal geomagnetic components and atmospheric pressure.

The Fourier decomposition program used in our paper contained a small error that affected the calculation of the temperatures as well as the V – I colors inferred for the RRab stars. The temperatures that appear in Table 6 in the published article are slightly overestimated, and the V – I colors underestimated. A corrected version of Table 6 is presented below.

A new and original stereo imaging method is introduced to measure the altitude of the OH nightglow layer and provide a 3D perspective map of the altitude of the layer centroid. Near-IR photographs of the OH layer are taken at two sites separated by a 645 km distance. Each photograph is processed in order to provide a satellite view of the layer. When superposed, the two views present a common diamond-shaped area. Pairs of matched points that correspond to a physical emissive point in the common area are identified in calculating a normalized cross-correlation coefficient (NCC). This method is suitable for obtaining 3D representations in the case of low-contrast objects. An observational campaign was conducted in July 2006 in Peru. The images were taken simultaneously at Cerro Cosmos (12°09′08.2″ S, 75°33′49.3″ W, altitude 4630 m) close to Huancayo and Cerro Verde Tellolo (16°33′17.6″ S, 71°39′59.4″ W, altitude 2272 m) close to Arequipa. 3D maps of the layer surface were retrieved and compared with pseudo-relief intensity maps of the same region. The mean altitude of the emission barycenter is located at 86.3 km on July 26. Comparable relief wavy features appear in the 3D and intensity maps. It is shown that the vertical amplitude of the wave system varies as exp (Δz/2H) within the altitude range Δz = 83.5–88.0 km, H being the scale height. The oscillatory kinetic energy at the altitude of the OH layer is comprised between 3 × 10−4 and 5.4 × 10−4 J/m3, which is 2–3 times smaller than the values derived from partial radio wave at 52°N latitude.

We present the results of a search for variable stars in the globular cluster NGC 5286, which has recently been suggested to be associated with the Canis Major dwarf spheroidal galaxy. 57 variable stars were detected, only 19 of which had previously been known. Among our detections one finds 52 RR Lyrae (22 RRc and 30 RRab), 4 LPV's, and 1 type II Cepheid of the BL Herculis type. Periods are derived for all of the RR Lyrae as well as the Cepheid, and BV light curves are provided for all the variables. The mean period of the RRab variables is = 0.656 days, and the number fraction of RRc stars is N(c)/N(RR) = 0.42, both consistent with an Oosterhoff II (OoII) type -- thus making NGC 5286 one of the most metal-rich ([Fe/H] = -1.67; Harris 1996) OoII globulars known to date. The minimum period of the \RRab's, namely Pab,min = 0.513 d, while still consistent with an OoII classification, falls towards the short end of the observed Pab,min distribution for OoII globular clusters. As was recently found in the case of the prototypical OoII globular cluster M15 (NGC 7078), the distribution of stars in the Bailey diagram does not strictly conform to the previously reported locus for OoII stars. We provide Fourier decomposition parameters for all of the RR Lyrae stars detected in our survey, and discuss the physical parameters derived therefrom. The values derived for the RRc's are not consistent with those typically found for OoII clusters, which may be due to the cluster's relatively high metallicity -- the latter being confirmed by our Fourier analysis of the ab-type RR Lyrae light curves. We derive for the cluster a revised distance modulus of (m-M)V = 16.04 mag. (ABRIDGED)

Abstract— On September 15, 2007, a bright fireball was observed and a big explosion was heard by many inhabitants near the southern shore of Lake Titicaca. In the community of Carancas (Peru), a 13.5 m crater and several fragments of a stony meteorite were found close to the site of the impact. The Carancas event is the first impact crater whose formation was directly observed by several witnesses as well as the first unambiguous seismic recording of a crater‐forming meteorite impact on Earth. We present several lines of evidence that suggest that the Carancas crater was a hypervelocity impact. An event like this should have not occurred according to the accepted picture of stony meteoroids ablating in the Earth's atmosphere, therefore it challenges our present models of entry dynamics. We discuss alternatives to explain this particular event. This emphasizes the weakness in the pervasive use of “average” parameters (such as tensile strength, fragmentation behavior and ablation behavior) in current modeling efforts. This underscores the need to examine a full range of possible values for these parameters when drawing general conclusions from models about impact processes.

Introduction: On September, 15th, 2007, 16:45 hours UT, the impact of a meteorite took place in the Carancas community, Desaguadero town, Chucuito city, region of Puno, Peru, located near the frontier with Bolivia. The geodesic coordinates of the center of the crater measured with GPS are: Latitude 16°39' 52.2 South, Longitude 69°02' 38.8 West, Altitude 3,824 m above sea level. Formed impact Crater is approximately 13.5 m in diameter (Fig. 1).

EARTH G. Tancredi, J. Ishitsuka, P. Schultz, R. S. Harris, P. Brown, D. Revelle, K. Antier, A. Le Pichon, D. Rosales, E. Vidal, D. Pavel, A. Dalmau, S. Benavente, P. Miranda, G. Pereira, M. E. Varela, L. Sanchez 1 Dpto. Astronomia, Fac. Ciencias, Montevideo, Uruguay, gonzalo@fisica.edu.uy, 2 Inst. Geofisico del Peru 3 Dept. Geological Sciences, Brown University, USA, 4 Dept. of Physics and Astronomy, University of Western Ontario, Canada, 5 EES-2, Atmospheric, Climate and Environmental Dynamics Group, Los Alamos National Laboratory, USA, 6 Commissariat a l’Energie Atomique, Centre DAM, France, 7 Univ. Nacional del Altiplano, Peru, 8 Planetario Max Schreier, Univ. Mayor de San Andres, Bolivia, 9 CASLEO, Argentina, 10 Inst. Ciencias Geologicas, Uruguay

The emission of the upper atmosphere introduces an additional variable component into observations of astronomical objects in the NIR 700–3,000 nm range. The subtraction of this component is not easy because it varies during the night by as much as 100% and it is not homogeneous over the sky. A program aimed at measuring and understanding the main characteristics of the atmospheric NIR emission was undertaken. A 512 × 512 CCD camera equipped with a RG780/2 mm filter is used to obtain images of the sky in a 36° × 36° field of view. The intensities of a given star and of the nearby region devoid of star in a 439 arcmin 2 area are monitored during periods of time of several hours. The sky intensity measured in the 754–900 nm bandpass, reduced to zenith and zero airmass is comprised between mag20 and mag18.5 per arcsecond 2 . A diminution by a factor of two during the night is frequently observed. Intensity fluctuations having an amplitude of 15% and periods of 5–40 min are present in the images with a structure of regularly spaced stripes. The fluctuations of the NIR sky background intensity are due to (1) the chemical evolution of the upper atmosphere composition during the night and (2) dynamical processes such as tides with periods of 3–6 h or gravity waves with periods of several tens of minutes. We suggest that a monitoring of the sky background intensity could be set up when quantitative observations of astronomical objects require exposure times longer than ~10 min. The publication is illustrated with several video films accessible on the web site http://www.obs-besancon.fr/nirsky/ . Enter username: nirsky and password: skynir.

The hydroxyl nightglow layer is an excellent tracer of the dynamical processes occurring within the mesosphere. A new stereo-imaging method is applied that not only measures the altitude of the airglow layer but also provides a three-dimensional map of the OH-layer centroid heights. A campaign was conducted in July 2006 in Peru to obtain NIR images of the OH nightglow layer which were simultaneously taken for two sites separated by 645km: Cerro Cosmos (12°09′08.2″S, 75°33′49.3″W, altitude 4630m) and Cerro Verde Tellolo (16°33′17.6″S, 71°39′59.4″W, altitude 2330m). Data represented by pairs of images obtained during the nights of July 26–27 and 28–29 are analyzed to yield satellite-type views of the wave field. These are obtained by application of an inversion algorithm. In calculating the normalized cross-correlation parameter for the intensity, three-dimensional maps of the OH nightglow layer surface are retrieved. The mean altitude of the emission profile barycenter is found to be at 87.1km on July 26 and 89.5km on July 28. In these two cases the horizontal wavelengths determined are 21.1 and 24.6km with periods of 18 and 34min, respectively. A panoramic view of the OH nightglow emission obtained on July 29 at 8h51–9h26 UT is presented, in which the overall direction of the waves is found to be N–NW to S–SE, azimuth 150°–330° (counted from South). The wave kinetic energy density at the OH nightglow layer altitude is 3.9×10−4W/kg, which is comparable to the values derived from partial reflection radiowave data.

AbstractWe are in the process to transform a 32m antenna in Peru, used for telecommunications, into a Radio Telescope to perform Radio Astronomy in Peru. The 32m antenna of Peru constructed by NEC was used for telecommunications with communications satellites at 6 GHz for transmission, and 4 GHz for reception.In collaboration of National Institute of Information and Communications Technology (NICT) Japan, and National Observatory of Japan we developed an Antenna Control System for the 32m antenna in Peru. It is based on the Field System FS9, software released by NASA for VLBI station, and an interface to link PC within FS9 software (PC-FS9) and Antenna Control Unit (ACU) of the 32 meters antenna.The PC-FS9 controls the antenna, commands are translated by interface into control signals compatibles with the ACU using: an I/O digital card with two 20bits ports to read azimuth and elevation angles, one 16bits port for reading status of ACU, one 24bits port to send pulses to start or stop operations of antenna, two channels are analogue outputs to drive the azimuth and elevation motors of the antenna, a LCD display to show the status of interface and error messages, and one serial port for communications with PC-FS9.The first experiment of the control system was made with 11m parabolic antenna of Kashima Space Research Center-NICT, where we tested the right working of the routines implemented for de FS9 software, and simulations was made with looped data between output and input of the interface, both test were done successfully.With this scientific instrument we will be able to contribute with researching of astrophysics. We expect to into a near future to work at 6.7GHz to study Methanol masers, and higher frequencies with some improvements of the surface of the dish.