天文現象及活動

光學望遠鏡的原理及構造、反射式望遠鏡的磨製和測試、赤道式天文望遠鏡腳座和附件的製作與調校等。在實習期間，學員將會學習製造一具12厘米口徑的反射式天文望遠鏡。

◎實習
時間：
●2017.05.21(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.05.28(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.06.04(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.06.11(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.06.18(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.06.25(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.07.02(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
●2017.07.23(日) 10:00 ~ 12:30 或 14:00 ~ 16:30
地點：香港太空館活動室

◎講座
時間：
●2017.05.25(四) 19:00 ~ 20:00
●2017.06.01(四) 19:00 ~ 20:00
●2017.06.08(四) 19:00 ~ 20:00
●2017.06.15(四) 19:00 ~ 20:00
●2017.06.22(四) 19:00 ~ 20:00
地點：香港太空館演講廳

講者：
●黃隆 (坐井會資深會員)
●鄭家輝 (坐井會資深會員)
●黃永藍 (香港天文論壇版主)
導師：蔡建華 (坐井會資深會員)
名額：30
對象：15歲或以上

收費課程，2017.04.01起，參加者必須報名，先到先得

此活動由香港太空館主辦。

Plenary talks:- Twinkle twinkle dirty stars, how I wonder how you die

In the standard theory of stellar evolution, stars die and become white dwarfs, neutron stars, or black holes, depending on their masses. Many stars go through spectacular explosion and become supernovae before their final deaths. However, this standard theory ignores possible admixture of dark matter – invisible matter that interact only gravitationally and maybe weakly – and their effects on the stellar structure, even though dark matter is known to be the dominant form of matter in the universe. the speaker will briefly introduce work done in CUHK investigating dark matter admixed stars, particularly how they die!　
　
時間：2017.05.20(六) 09:30 ~ 10:00
地點：香港中文大學 科學館LT4
講者：朱明中 教授
語言：英語

#131

此活動由香港中文大學物理系主辦。

Invited talks:- Multi-scale Magnetic Field Orientation and its Observation

The role of magnetic fields is an important problem in star formation. We investigate the orientations of magnetic fields at different spatial scales by comparing the optical data with the single dish and interferometer data. We found that the magnetic field orientations are well correlated from 300 pc to 0.1-1 pc, and show a bimodal distribution when deep into ~0.01pc. In order to verify this result and further investigate the field morphology problem, our group is constructing a polarimeter, APol which will allow us to do experiment and get our own data.　
　
時間：2017.05.20(六) 11:15 ~ 11:40
地點：香港中文大學 科學館LT4
講者：Yapeng Zhang
語言：英語

#131

此活動由香港中文大學物理系主辦。

相關流星群：天蠍-人馬座流星雨群組(SAG)

出現日期：
4月15日至7月15日
極大日期(香港時間)：
5月20日(星期六)9時09分
月閃高峰期：
遲0.2小時

天頂每時出現率ZHR：5顆
速度：每秒30公里(低速)
亮度指標：2.5(中等)

輻射點(曆元2000)：
赤經16.5時/247°赤緯-22°

有關今次天象更詳細資料請按左下角「外部連結」

http://forum.hkas.org.hk/thread-9675-1-1.html

物理系學生會議：銀河尺度內量子效應 – 模糊暗物質宇宙模擬及大尺度結構

Talk:- Quantum Effect in Galactic Scale: Fuzzy Dark Matter Cosmological Simulation and Large Scale Structure

The Ultra-Light Axion (ULA) is a dark matter candidate with mass o(10^-22) eV and de Broglie wavelength of order kpc. Such an axion, also called the Fuzzy Dark Matter (FDM), thermalizes via the gravitational force and forms a Bose-Einstein condensate. Recent studies suggested that the quantum pressure from the FDM can significantly affect the structure formation in small scales, thus alleviating the so-called “small-scale crisis”. We develop a new technique to discretize the quantum pressure and illustrate the interactions among FDM particles in the N-body simulation. With our highly efficient algorithm, the largest scale cosmological simulation of FDM model has been performed. The non-trivial effect of quantum pressure on Large Scale Structure (LSS) has been revealed. The constraints from recent Lyman-alpha Forest observations are discussed.　
　
時間：2017.05.20(六) 13:30 ~ 13:45
地點：香港中文大學 科學館LT4
講者：Jiajun Zhang
語言：英語

#131

此活動由香港中文大學物理系主辦。

宇宙中危機四伏，強烈的太陽風暴、不可抵禦的近地天體撞擊事件及來源不明的伽馬射線暴都有可能於一瞬間令地球上全人類滅亡。講者將會在是次講座中向觀眾解說各項危害背後的成因及科學原理。

時間：2017.05.20(六) 15:00 ~ 16:30
地點：香港太空館演講廳
講者：
●丘澄峰 (星匯點委員)
●梁家榮 (星匯點委員)

免費講座，歡迎公眾參加，座位先到先得

此活動由香港太空館主辦。

物理系學生會議：貝氏變分法到參數估算重力波天文學

Talk:- Variational Bayesian to Parameter Estimation in Gravitational Wave Astronomy

The traditional way of conducting parameter estimation in gravitational-wave data analysis is done by obtaining the posterior and evidence through Markov-Chain Monte Carlo methods. These computational methods are time consuming as they rely on wandering randomly in parameter spaces of high dimensions. Instead of randomly sampling, variational Bayesian makes use of an approximated probability distributions, which resembles the true distribution. Minimizing the differences between the true and approximated distributions can then be a more directional way of conducting parameter estimation. In this presentation, we will discuss the possibility of implementing variational Bayesian to parameter estimation in gravitational-wave data analysis.　
　
時間：2017.05.20(六) 14:00 ~ 14:15
地點：香港中文大學 科學館LT4
講者：Adrian, K.W. Chung
語言：英語

#131

此活動由香港中文大學物理系主辦。

13時31分，海王星合月，海王星在月球北0.47度

物理系學生會議：速旋中子星循雙曲軌道接近大質量黑洞之動力學

Talk:- Dynamics of Fast Spinning Neutron Stars in a Hyperbolic Orbit near a Massive Black Hole

The trajectory of a non-spinning test particle is given by the geodesics equations. However, when the test particle is spinning, it’s spin interacts with the orbit and the background curvature, giving rise to interesting dynamical behaviors, which in turn can probe the background space-time structure. In this research, we study a fast spinning pulsar orbiting in a hyperbolic orbit around a massive black hole. Millisecond pulsars are very accurate “clock” in the universe. Their abundant existence is predicted by various studies, which however, are not verified, due to the limit of pulsar timing techniques and the complicated pulse profiles of a accelerating pulsar. In this research, the spin problem in relativity and the dynamical features of such system were reviewed and studied. An orbital shift of ~100km and a velocity shift of ~1 km/s are observed, and the former will correspond to a shift of arrival time of pulse ~100μs, while the latter is related to the gravitational wave memory effect. The result of this study will provide useful insights for both the gravitational wave detector LISA, and the pulsar timing array SKA.　
　
時間：2017.05.20(六) 13:45 ~ 14:00
地點：香港中文大學 科學館LT4
講者：Jiale Kaye Li
語言：英語

#131

此活動由香港中文大學物理系主辦。

時間：2017.05.20(六) 17:00 ~ 18:15
地點：澳門科學館天文館
講者：龍嘉穎 Lydia Lung (天文匯)
語言：英語

免費活動，惟參加者必須於當日講座前先到售票處領取門票

#95

此活動由澳門科學館主辦。