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1.
The recent development and data collection results of the Astrobiology Instrumentation for Meteor Imaging and Tracking (AIM-IT)
system, has demonstrated an ability to point narrow field-of-view instruments at transient events such as meteors. AIM-IT
uses the principle of tracking moving objects via a paired set of relay mirrors along with an integrated hardware/software
solution, to acquire and track meteors in real-time. Development of the instrument has progressed from a prototype rocker-box
system through more recent use of a fast response mirror system during several meteor shower campaigns. Several narrow field
of view instruments have been deployed using AIM-IT including high spatial resolution video, high frame rate video, and meteor
spectrographic equipment. Analysis of the imagery shows evidence for meteor fragmentation in as many as 20% of the meteors
tracked thus far. The success of the AIM-IT technology in tracking meteors during their luminous flight provides a new tool
in enhancing the capabilities and data volume that can be obtained with existing narrow field of view instruments. 相似文献
2.
P. Jenniskens P.S. Gural L. Dynneson B.J. Grigsby K.E. Newman M. Borden M. Koop D. Holman 《Icarus》2011,216(1):40-61
First results are presented from a newly developed meteoroid orbit survey, called CAMS – Cameras for Allsky Meteor Surveillance, which combines meteor detection algorithms for low-light video observations with traditional video surveillance tools. Sixty video cameras at three stations monitor the sky above 31° elevation. Goal of CAMS is to verify meteor showers in search of their parent comets among newly discovered near-Earth objects.This paper outlines the concept of operations, the hardware, and software methods used during operation and in the data reduction pipeline, and accompanies the data release of the first batch of meteoroid orbits. During the month of November 2010, 2169 precisely reduced meteoroid trajectories from 17 nights have an error in the apparent radiant of the trajectory <2° and error in speed <10%. Median values of the error are 0.31° and 0.53 km/s, respectively, sufficient to resolve the intrinsic dispersion of annual meteor showers and resolve minor showers from the sporadic background. The limiting visual magnitude of the cameras is +5.4, recording meteors of +4 magnitude and brighter, bright enough to stand out from the mostly fainter sporadic meteors detected as under dense radar echoes.CAMS readily detected all established showers (6) active during the clear nights in November. Of the showers that needed confirmation, we confirm the theta Aurigids (THA, IAU#390), the chi Taurids (CTA, IAU#388), and the omicron Eridanids (OER, IAU#338). We conclude that the iota November Aurigids (IAR, IAU#248) are in fact the combined activity of the theta Aurigids and chi Taurids, and this shower should be dismissed from the list. Finally, there is also a clustering consistent with the zeta Cancrids (ZCN, IAU#243), but we cannot exclude that this is lower perihelion dust belonging to the Orionid shower.Data are submitted to the IAU Meteor Data Center on a semi-regular basis, and can be accessed also at http://cams.seti.org. 相似文献
3.
R. J. Weryk P. G. Brown A. Domokos W. N. Edwards Z. Krzeminski S. H. Nudds D. L. Welch 《Earth, Moon, and Planets》2008,102(1-4):241-246
We have developed an automated network of all-sky CCD video systems to detect medium–large meteoroids ablating over Southern
Ontario, Canada. The system currently consists of five stations with the largest baseline being 180 km. Each site runs a video
rate recorder with sufficient resolution to determine meteoroid trajectories with a typical precision of about 300 m but no
worse than 1 km. The sensitivity of the camera is close to a stellar visual magnitude of +1 which allows for astrometric calibrations
using field stars. Photometric procedures have also been developed and tested. The system has a limiting magnitude for meteors
of about −2 with the current detection algorithm. 相似文献
4.
Peter S. Gural 《Earth, Moon, and Planets》2008,102(1-4):269-275
An ever increasing variety of electronic instrumentation is being brought to bear in meteor studies and analysis, with unique
meteor detection challenges arising from the attempt to do automated and near real-time processing of the imagery. Recent
algorithm developments in the literature have been applied and implemented in software to provide reliable meteor detection
in all-sky imagers, wide-field intensified video, and narrow field-of-view telescopic systems. The algorithms that have been
employed for meteor streak detection include Hough transforms with phase coded disk, localized Hough transforms with matched
filtering, and fast moving cluster detection. They have found application in identifying meteor tracks in the Spanish Fireball
Network all-sky images, detailed analysis of video recordings during the recent Leonid meteor storms, and development of a
detection/cueing technology system for rapid slew and tracking of meteors. 相似文献
5.
The IAU Meteor Data Center in Lund has acted as a central depository for meteor orbits obtained by photographic, video and
radar techniques. The database of precisely reduced photographic meteors contains data on 4581 meteor orbits obtained by 17
different stations or groups in the period 1936–1996. The orbital and geophysical data are available in two separate files
as well as in an alternative file with the merged data. In various studies of meteoroid streams as well as in studies of the
sporadic meteor background, it is often necessary to utilize both the orbital and the geophysical data files. Since the database
is a compilation of partial, not perfectly compatible catalogues from many observing stations, the merging of parameters from
one data set to another may sometimes present problems. The present contribution is a note on some problems encountered in
the merging procedure. Moreover, it is evident that the database includes a small amount of erroneous data – either in the
observations or in the subsequent data reductions. The latter error is not surprising in view of the lack of modern computers
at several stations in the past. A final, corrected version of the IAU MDC Lund photographic meteor orbits (eq. 2000.0) can
now be requested through the homepage of the Astronomical Institute, Slovak Academy of Sciences (http://www.astro.sk/~ne/IAUMDC/Ph2003/database.html). 相似文献
6.
Wayne N. Edwards Peter G. Brown Robert J. Weryk Douglas O. ReVelle 《Earth, Moon, and Planets》2008,102(1-4):221-229
Recent observations using the newly installed Elginfield infrasound array in coordination with the Southern Ontario all-sky
meteor camera network and Canadian Meteor Orbit Radar (CMOR) has shown that the number of meteors producing infrasound at
the Earth’s surface is more frequent than previously thought. These data show the flux of meteoroids capable of producing
infrasound at the ground is at least 1/month and is limited to meteors with peak visual brightness above −2. Comparisons to
current meteor infrasound theory show excellent agreement with amplitude and period predictions for weakly non-linear shock
waves using a realistic vertically inhomogeneous atmosphere. Similar predictions show isothermal assumptions underestimate
the amplitude by orders of magnitude. 相似文献
7.
M. D. Campbell-Brown 《Earth, Moon, and Planets》2004,95(1-4):521-531
Optical observations remain the most widely used method for studying meteors, even though they are limited by daylight and
weather conditions. Visual observations have been used throughout history. They lack the precision of other methods, since
they rely on the judgment of observers for trajectory information. However, since no special equipment is required, visual
observations are widespread, and can give valuable information on the activity profile of showers. Photographic observations
are much more precise. Rotating shutters allow velocities to be determined, and networks of cameras permit the height and
trajectory of a meteor to be calculated. Except for the Super-Schmidt observations at Harvard, most photographic observations
record only meteors brighter than 0 magnitude. Video observations, using image intensifiers, can record much fainter meteors
down to +7 magnitude. Processing is becoming very automated, so that large quantities of data can be reduced relatively easily.
Most video cameras have much lower precision than photographic cameras, but new technologies are changing this. Spectral observations
of meteors, using video or photographic techniques, can be used to investigate the chemistry of meteoroids, while telescopic
observations allow measurements to be extended to much fainter meteors (+10 or fainter). 相似文献
8.
This paper describes the progress on the Virtual Meteor Observatory (VMO), a database which is being developed at ESA/RSSD to store video meteor observations and their derived orbits. The VMO was triggered by a discussion which took place at the first Meteor Orbit Determination (MOD) workshop in Roden, The Netherlands, in September 2006. Representatives of 15 groups working on the determination of meteor orbits and working with the resulting orbits discussed the design and implementation of a database which would combine different meteor orbit datasets. From this the concept of the VMO was born, which will, in the long run, allow accessing meteor observations via the internet. In the beginning, it will focus on meteor orbit data obtained with video systems. This paper presents the architectural design of the database as it has been defined in the meantime. 相似文献
9.
10.
流星光学监测网是定位陨石和观测火流星的基础科研设施. 流星光学监测系统利用光学相机高速采集天空图像, 使用嵌入式系统实时处理数据, 能够快速识别流星并获取流星位置和陨石落点信息, 是构成流星监测网的关键仪器. 为提高流星光学监测系统获取信息的实时性及准确性, 提出了一种基于嵌入式人工智能设备的流星光学监测系统. 该系统由软件及硬件部分组成: 硬件部分包括观测设备(商用高空抛物摄像头)以及数据处理设备(嵌入式人工智能设备); 软件部分运行于数据处理设备内, 主要包括控制界面模块、流星监测模块、数据管理模块. 实际工作时, 摄像头采集天空视频信息, 流星监测模块从视频流中实时监测流星并存储包含流星视频的数据, 数据管理模块将流星位置信息实时传回数据中心用于预警. 观测结束后, 将原始观测数据同步至数据中心用于后续科学研究. 在整个系统中, 流星监测模块决定了整个监测系统的实时性及准确性. 该系统采用嵌入式人工智能设备与人工智能算法结合的方法构建流星监测模块. 通过使用实测数据对搭载监测模块性能进行测试, 结果表明: 流星监测模块能够达到0.28%的低误检率以及100%的召回率, 且数据处理速度达到了Mobilenetv2的8倍. 进一步将包含监测模块的整个流星光学监测系统部署于太原理工大学-张壁古堡远程天文台, 通过实测表明流星光学监测系统实用中能达到100%的召回率和较低的误检率. 相似文献
11.
Meteor radar observations of ionized trails in the Earth’s atmosphere provide observations that do not depend on weather conditions
and time of day and provide good statistics for analysis. Further development in the new quasitomographic analysis of the
goniometric data of the Kazan meteoric radar has revealed a number of very weak meteoric streams with rates of more than 5–6
meteors per day. In addition to the known large meteor showers, we have found up to as many as 1000 small showers per month
that we have named microshowers. We shall operationally define a microshower as the minimal meteoric stream which can be detected
with the Kazan meteoric radar while quasitomographic procedures of processing interferometer data are used. 相似文献
12.
The structures of the meteor streams of cometary origin—Draconids, Ursids, Perseids, and Lyrids—and the streams presumably connected with asteroids—Taurids and α-Capricornids—are compared. The comparative analysis was performed by the mass distribution of meteoroids in the stream and the activity profile for the meteors with the maximum recorded stellar magnitude +3 m and brighter. Visual observations of 1987–2008 from the database of the International Meteor Organization (IMO) and earlier sources were considered. It has been shown that the structures of the meteor streams of cometary and, presumably, asteroidal origin differ somewhat by the activity profile and the mass distribution of meteoroids in the cross-section of a stream along the Earth’s orbit. 相似文献
13.
M. Hajduková Jr. 《Earth, Moon, and Planets》2008,102(1-4):67-71
The hyperbolic meteor orbits among the 4,581 photographic and 62,906 radar meteors of the IAU MDC have been analysed using
statistical methods. It was shown that the vast majority of hyperbolic orbits has been caused by the dispersion of determined
velocities. The large proportion of hyperbolic orbits among the known meteor showers strongly suggests the hyperbolicity of
the meteors is not real. The number of apparent hyperbolic orbits increases inversely proportional to the difference between
the mean heliocentric velocity of meteor shower and the parabolic velocity limit. The number of hyperbolic meteors in the
investigated catalogues does not, in any case, represent the number of interstellar meteors in observational data. The apparent
hyperbolicity of these orbits is caused by a high spread in velocity determination, shifting a part of the data through the
parabolic limit. 相似文献
14.
J. D. Mathews S. J. Briczinski D. D. Meisel C. J. Heinselman 《Earth, Moon, and Planets》2008,102(1-4):365-372
Radio science and meteor physics issues regarding meteor “head-echo” observations with high power, large aperture (HPLA) radars,
include the frequency and latitude dependency of the observed meteor altitude, speed, and deceleration distributions. We address
these issues via the first ever use and analysis of meteor observations from the Poker Flat AMISR (PFISR: 449.3 MHz), Sondrestrom
(SRF: 1,290 MHz), and Arecibo (AO: 430 MHz) radars. The PFISR and SRF radars are located near the Arctic Circle while AO is
in the tropics. The meteors observed at each radar were detected and analyzed using the same automated FFT periodic micrometeor
searching algorithm. Meteor parameters (event altitude, velocity, and deceleration distributions) from all three facilities
are compared revealing a clearly defined altitude “ceiling effect” in the 1,290 MHz results relative to the 430/449.3 MHz
results. This effect is even more striking in that the Arecibo and PFISR distributions are similar even though the two radars
are over 2,000 times different in sensitivity and at very different latitudes, thus providing the first statistical evidence
that HPLA meteor radar observations are dominated by the incident wavelength, regardless of the other radar parameters. We
also offer insights into the meteoroid fragmentation and “terminal” process. 相似文献
15.
The results of observations of the Orionid meteor shower are given in the period from 2006 to 2008. Observations were carried out using a highly sensitive camera FAVOR (FAst Variability Optical Registrator) a limiting magnitude of above +11.0m (for stars) and a field of view of 18° × 20°. Over the period of the shower from October 2 to November 7, 2006–2008, there were 3713 meteors. 449 of these meteors were associated with the Orionid meteor shower. The distributions of Orionid meteors by the stellar magnitude is presented. It turned out that most of meteors (65%) of this shower have a brightness of +5.0m-+7.0m. On each night of observation the index of meteor activity was calculated for Orionids. 相似文献
16.
In the last 20 years, with the development of the CCD and image intensifiers, the use of small flexible video meteor observation systems has gradually increased, with the prospect that one day video observation will replace the visual observation and ordinary photographic observations. In this paper we report on the research and development of the No.1 meteor-comet video camera system of Yunnan Observatory and some preliminary observed results. The system consists of 5 changeable modules; it has a 36° large-field camera dedicated to the observation of meteors, with which a magnitude 6 star can be recorded on a single frame with an accuracy of about 0.2 mag. We also present a comparison of the video camera system with the traditional photographic system, and outline the merits, possible improvements and future development of the video system. 相似文献
17.
Detlef Koschny Jorge Diaz del Rio Rodrigue Piberne Marek Szumlas Joe Zender André Knöfel 《Earth, Moon, and Planets》2004,95(1-4):255-263
Both amateur and professional meteor groups are more frequently using Low-Light level TV (LLTV) systems to record meteors.
Double-station observations can yield orbit data. However, data analysis normally is still done by hand and thus time consuming.
This paper addresses the question of whether available automated tools can be used to determine reasonably accurate orbits
with minimum human intervention. The European Space Agency performed several observing campaigns to observe the Leonid meteor
stream. In November 1999, the ESA meteor group was stationed at two locations in Southern Spain, in November 2001 at two stations
close to Broome in North-Western Australia. Double-station observations with LLTV systems were conducted. The data was recorded
on S-VHS video tapes. The tapes were processed using automatic detection software from which meteor heights, velocities and
radiants were computed. This paper shows the results for the two maximum nights. The radiants determined in 1999 show a very
large scatter due to unfortunate observing geometry and inaccurate position determination since one of the cameras was moving
because of the wind. The 2001 data is excellent and the radiant was determined to be at RA = 153.96°±0.3° and Dec = 21.09°±0.2°.
The error bars for individual meteor radiants are about 0.2° to 0.4°. This demonstrates that is indeed possible to determine
good radiant positions using totally automated tools. Orbits, on the other hand, are not well defined due to the fact that
the velocity of individual meteors shows large errors. Reasons for this are described. 相似文献
18.
We have carried out multi-station TV observations since 1994 in order to determine the orbit of the Arietid daytime meteor
stream. In 1999, one possible Arietid meteor was recorded by our simultaneous observations and its orbit was determined. In
2003, two Arietid meteors were observed from two stations of our observing site, those orbits were determined precisely, the
orbital elements were in good agreement with each other. This is the first time that determination of the precise orbit of
the Arietids has been made from optical observations. The orbit of these Arietid meteors, and comparison with the orbit obtained
from radar observations are discussed. 相似文献
19.
We tested four criteria used for discrimination between asteroidal and cometary type of orbits: Whipple criterion K, Kresak
criterion Pe, Tisserand invariant T and aphelion distance Q. To estimate their reliability, all criteria were applied to classify
the 2225 orbits of NEAs and 582 orbits of comets, for several epochs spanning the time interval of 40 thousands years. The
Q-criterion produced the smallest number of exceptions and has shown the best stability. The biggest number of exceptions
and the biggest variations are obtained for the K-criterion. We applied the Q-criterion to classify meteor orbits from the
IAU Meteor Data Center and the video meteor orbits available on the Web sites. Among the sporadic radar orbits, as well as
among the mean orbits of meteor streams a strong preponderance of asteroid-type orbits was observed. In case of the photographic
and video meteors a weak preponderance of cometary and asteroidal orbits was found, respectively. 相似文献
20.
The state of the art in the theory of processing of visual observations of meteor streams is considered. Of the three widely used methods of visual-observation processing, the method developed at the Engel'gardt Astronomical Observatory provides the highest accuracy of conversion to the hourly rate of meteors. For the first time, the dependence of the fine structures of the Geminid, Perseid, and Leonid streams on the minimum detected mass of meteor bodies is obtained from visual observations. A shift in the position of an activity maximum for smaller masses in the direction of lower solar longitudes is confirmed for the Geminids. For the Perseids, an activity maximum for meteor bodies with mass exceeding 0.01 g, sets in earlier than for smaller particles. In the Leonid swarm, no correlation was found between the node longitude of the mean swarm orbit and mass of meteor bodies. 相似文献