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Qadi Zada computed sin 1 [degrees] to an accuracy of 10-12 (if expressed in decimals), as did al-Kashi. J. J O’Connor and E.F Robertson: Arabic Mathematics, a forgotten brilliance;  muslim heritage wiki scientificlib   sine of one degree: First, using the formula  sin(a/2)=sqrt((1-cosa)/2) and the already known value of the cosine of 36 degrees, the value of sin18 and therefore cos18 can be calculated. Repeating the same procedure, sin9 can be found. Then, using the formula  sin(a-b)=sin(a) cos(b)-sin(b) cos(a) for a=45, b=18, the value of sin27 is obtained. Using the same formula for a=30, b=27, we arrive at the value for sin3. At this point, the formula  sin(3)=3sin(1)-4(sin(1))^3  can yield the value for x=sin1, provided we can solve the equation  4x^3-3x+q=0, where q=sin3.  The methods of solving cubic equations however, such as the one considered here, were not available to 15th century mathematicians. The Samarkand scientists then proceeded by rewriting the equation in the form

  东方红五号卫星平台（DFH-5）是中国下一代地球同步轨道大型卫星公用平台，作为中国卫星技术的重要突破，将使用多种先进技术，其超大型的卫星平台质量达到10吨，远远超出了现有长征三号乙的运载能力，将使用长征五号火箭进行发射。相较于前一代的东方红四号卫星平台（DFH-4），东五平台采用了更先进的桁架结构和电推技术。东五平台的有效载荷质量将达到 1200-2000 千克，电源功率达到15-20千瓦。作为通信卫星使用时，携带的转发器数量可达100多路。这些性能指标都超过了东四平台，可以更好地满足未来通信、科学探测和微波遥感类卫星的需求，同时也兼顾了光学遥感类卫星的需求。 东五平台还将使用二次展开十字太阳翼和可展开式热辐射器等多项新技术。二次展开十字太阳翼是一种新型的太阳能电池板，可以在太空中展开以获取更多的太阳能，提高卫星的能量利用效率。可展开式热辐射器则可以在卫星的工作时展开，将卫星产生的热量散发出去，保证卫星的温度稳定，避免因为过热而导致的故障。

 From Korea study of Cheonsang-yeolcha-bunyajido (天象列次分野之圖) mean is -0.39 du(古度） delta ( 1 SD) = 3.9 du 365.26 du = 360 degrees  some says 古度 is 渾儀上"定極環" 長度距離, cf 黃一農 The bigger errors in some asterisms may be due to the astronomical instruments, eg armillary sphere in use. The rings may obstruct accurate alignment , especially polar distance of 96 to 100 du From Xiaochun Sun, Suzhou Astronomical Planisphere (苏州石刻天文图)of the thirteenth century, the error is less than 1.5 degrees 大統通占，用Fourier transform, 計算系統誤差： 一二四七年（淳祐七年）黄图在乎江府复刊，即现存的苏州天文图。崇宁年间观测到的记录，部分载入纪元历内，所测二十八宿距度星的平均误差绝对值只有0°.15 reference 極星箕古度考 - 黃一農 researchgate PMO sun  孫小淳 Huoyunjn   Academia   BonnetBidaud

 Kaavo Paavolainen  brothy, shoyu-miso-umami bombs, with kombucha-like aromatics, apparitions of acidity and decidedly uncoffeelike character. 日釀生技咖啡 Christopherferan   BaristaMagazine   Fermentation association  

  There is one major advantage to GC sniffing. The  human nose  can sometimes detect scents from compounds that are at such a low concentration, they're unable to be picked up by mass spectrometry. In this case, although six compounds appeared to contribute to the intense fruity flavor and the raspberry scent of the fermented coffee, the team was only able to identify three of them: 2-methylpropanal, 3-methylbutanal and ethyl 3-methylbutanoate. Phy   Sca

 Removed from Google Play Nov 22 Project Zero: researchers at Google’s Project Zero warned about active attacks on Samsung mobile phones which chained together three security vulnerabilities that Samsung patched in March 2021, and which would have allowed an app to add or read any files on the device. Google said it believes the exploit chain for Samsung devices belonged to a “commercial surveillance vendor,” without elaborating further. The highly technical writeup also did not name the malicious app in question. Feb 23  D arkNavy 深藍洞察 researchers at the Chinese security firm DarkNavy published a blog post purporting to show evidence that a major Chinese ecommerce company’s app was using this same three-exploit chain to read user data stored by other apps on the affected device, and to make its app nearly impossible to remove. DarkNavy likewise did not name the app they said was responsible for the attacks. In fact, the researchers took care to redact the name of the app from multipl

因為北京故宮中軸線及其他古建築 偏離 了子午線2~3度 所以拍懸日會在春分秋分前或後2,3天為最佳時刻   天壇的sunpath diagram: Topocentric spring equinox for Temple of Heaven 2023( in UTC): next equinox:  2023/3/20 21:24:13 next solstice:  2023/6/21 14:57:54 next equinox:  2023/9/23 06:49:58 next solstice:  2023/12/22 03:27:07 Temple of Heaven lat, lon: 39:52:56.0 116:24:23.0 topo sun az, alt[]:  80:39:26.8 -10:59:48.6 topo next sunrise az, alt[]:  2023/3/20 22:17:06 89:14:27.1 -0:16:03.6 topo next sunrise az, alt[]:  2023/3/21 22:15:29 88:43:34.4 -0:16:03.3 topo next sunrise az, alt[]:  2023/3/22 22:13:52 88:12:42.9 -0:16:03.1 topo next sunrise az, alt[]:  2023/3/23 22:12:15 87:41:53.1 -0:16:02.8 2023年, 最接近天壇的西天門, 東天門方向是在 北京時間3月23日 6：13：52 冬至  皇穹宇 YouTube 中 1:05-1:10 Temple of Heaven lat, lon: 39:52:56.0 116:24:23.0 topo sun az, alt[]:  168:24:11.4 25:49:34.5 UTC topo next 5 min transit az, alt[]:  2023/12/21 04:07:09 178:43:01.1 26:42:06.1 topo next 5 min transit az, alt[]:  2023/12/22 04:07:39 178:43:01.4 26:41:53.0 topo next 5 min tr

co-orindate: 8.4828° N, 76.9436° E It is located just ~8 degrees north of Equator, so during equinox, the sun sets almost vertically.   the temple is ~35 m wide, 35 m tall. the five stories with doors are roughly 21 m apart vertically. Half hour before equinox sunset, azimuth is 269 degrees Equinox sunset, azimuth is 270 degrees So if the window is enough wide, then sunset will appear in all 5 windows say 200 m away from the temple, the sun travels in horizontal distance = tan ( 1) * 200 = 3.5 m. But there are only 5 windows in this 7 story building, so the sun travels through these windows  3.5 x 5 / 7 = 2 m horizontally  from photo, widest window(at first floor) is only around 1.4 m wide, so the windows are very likely not vertically aligned, but tilted by say 0.5 degrees along north-south direction, or 0.6 m horizontally. Watch the youtube video above 0:48 - 0:55   please note the windows are not the same sizes,  most narrow at top floor, and wider when you go down each storey. The

 From Cuiv Grade S ( superb), best of the best, don't care the price tag Vixen SXD2  Ioptron CEM70,  (discontinued CEM60) Grade A ( best) SkyWatcher EQ6-R Pro Grade B ( very good, needs some tweaking and love) Ioptron CEM26 (discontinued CEM25) Vixen AP-WM SW Adventurer GTI (?) SW Az Eq5 GT Grade D (entry level) MEADE LT6 Ioptron Smart Eq pro Grade E ( worst) Hobym Crux Traveller 140  Harmonic mount From darkframe optics EQ32 (for 5KG payload, 2.8 arcsec pix) AVX HEQ5,EQ6R, CEM70, CEM120 From Wido , blog beginners: Criteria: EQ mount, Goto, guide point, ASCOM, 10-15kg payload  EQM-35, AVX, EXOS2-GT, IOptron GEM28, CEM26, HEQ5 Pro, Orion Sirius EQ-G Reference: EQM35 Pro  firmware update  v3.15

春分 - 太陽直射赤道 Three facts  1. In each year when Earth orbits around the Sun, There are two moments that the Sun is positioned directly over Earth's equator, called as equinoxes. This happens in March and in September. March equinox is also called Vernal Equinox 每年當地球環繞太陽公轉時，有兩時刻太陽垂直照射在地球赤道。三月為春分，九月為秋分。 2. 1st day of astronomical spring ( northern hemisphere)天文學上的春季第一天(北半球) 3 . 二十四節氣中的第四節氣 當太陽到達視地心視黃經apparent geocentric ecliptic longitude為0度的時刻（ geocentric, not topocentric) is 春分点是黄道相对天赤道的升交点，是现代天文学上标记和度量天体位置和运动的两个重要坐标系——天球黄道坐标系和赤道坐标系的计量零点，在天文学上有重要意义。 View from Space,   Earth's rotation axis pointing vertical 太陽垂直照射在地球赤度 (sub solar point) Showing the change of terminator's inclination wrt Earth's rotation axis 從太空上看地球, 春分的時刻 地球的 solar terminator陰影 與地球轉軸是同向，Earth's rotation axis is directly perpendicular to the Sun-Earth line, tilting neither toward nor away from the Sun，南北两半球获得相等的光照（illumination) View from plane of Earth's orbit   傳統上會形容春分為晝夜平分,是否正確呢？ 史書： 《明史·历一》说：

 Laser beam  projects direct to your retina  Using a laser and a scanning mirror MEMS ( similar to laser projector tech) Dreamnews   QD Laser Retissa   NEDO 投影方式 レーザ網膜走査 (第2世代) laser retinal scan 光源 RGB 半導体レーザ (R:640nm, G:515nm, B:465nm Typ.) 水平視野角 約26度 アスペクト比> 16:9 解像度 720P (1,280 x 720) 相当 色 8bitフルカラー（256諧調） 更新レート 60Hz 明るさ ＜0.39?W 映像入力 HDMI Type A (1920x1080 60p/1280x720 60p/ 720x480 60p/640x480 60p) 音声出力 ステレオミニジャック (Φ3.5mm) 電源入力 DC 5V (USB Micro B) 電源出力 DC 5V, 500mA (USB Type-A) バッテリ容量 3,880mAh 駆動時間 約200分 (外部給電時約136分) サイズ(W x H x D) プロジェクタ部：65 x 20 x 83.5 mm 本体部：74 x 150 x 29.5 mm 重量 プロジェクタ部： 約40g 本体部：約260g List price ¥250,000 - 298,000 Sony Retissa neoviewer Reference Semantics   Patent   Biel glasses   Diy Retinal projection    Lasermotor   濱松mems

1 download SDK and unzip (play memories "smart remote control" app) 2 use SSDP (Simple Service Discovery Protocol) to discover the camera and get the endpoint URL needed to call the API, as well as information about the supported functionality in the camera. 3  call the APIs by HTTP POST with JSON Examples  Yunswj Develop/code on Horizon SBC  , github , C++ API learning note   Mungewell  python, ssdp keyserSoze42  android, Java,JSON, Sony remote API Kiakiraki  python, REST (Akira Tsuruda) Kota65535 , Ruby, wrapper Jdesfossez  , simple python2, json,  partial storborg , python, ssdp falk0069  , SSDP, port 15740, PTP/IP Alpha-fairy  M5/ESP32/Arduino based. Excellent coding structure. PTP Bachmmmar , PTP IP, python based on falk0069 ThibaudM   json , Java  Yasinyildirim Libjson rpc ROS   Tzeny  , C# ASCOM, PCAP, tested on NEX-5T, Forked from Dougforpres erik smit , python, json ，DLNA petabite , python, sony rc api wrapper, wifi  rohhn bulb timelapse, android app, python, test

 Next Generation Vehicle Target is to halve the cost , bring down cost to $1000 for drive unit( motor ,inverter, controller etc) No rare earth  Iron nitride  Fe16N2 magnets, Niron magnetics. IEEE  says such magnet above 10 MGOe will be introduced for loudspeaker in late 2024. 30 MGOe in 2025. NdFeB magnet s in automotive traction motor is now typically 35 MGOe. NEDO . Patent Iron Nitride magnets are not new, and lusted in Alibaba Reduce use of Silicon carbide MOSFET s, pros and cons   Reduce working voltage down to 12 to 48 volt  switch to In house manufacture and integrated controllers. Cost analysis of BEV is forecast to override ICE in 2030 Mass production target: late 2024-25 reference: rohm EETimes SiC vs GAN  EEweb SiC in EVs Wiki Tetrataenite

 From NAIF  24/3 10:32:50 UTC, under 0.1 degree separation, geocentric conjunction timing For Hong Kong: Interesting LCSD  19:47 - 20:53 掩星組 19:47 - 20:54 Inthesky  16:35 - 19:27 NAOJ 19:47 20:53 Lunar-occultation  11:47:12 - 12:53:16 UTC IMCCE : 11:30:49 (UTC+1) (geocentric)   Best observation location will be India and Southern Africa

 Proposal:

  Videohelp  

大數據理論 若單單從兩三個變數, 出生時間及地點, 當時的卦算(hexgram, trigram)birth chart / Rasi chart 就能計數出整個人生的發展, 壽命, 有沒數據支持? correlation? 算得準是否偶然事件anecdotal? 現時互聯網數據上, 國際上有很多這方面研究, 相關性成大疑問, 特別是在醫學, 遺傳學genetics, DNA應有發現? 遺傳病, 生活習慣(吸煙, 飲酒), 環境污染,更能影響人的壽命吧 危疾, eg, 癌症, 重要器官疾病等: 做DNA檢測, 每年做身體檢查, 做帶氧運動, 有份危疾保障 不是更實際? cancer atlas   nationaljewish   CHP 防癌會  癌症預防 王亭之 星考

  Popular science  (2016) Metasurfaces are one kind of such diffractive optical elements with flat subwavelength implementations, which consist of quasiperiodic arrays of light resonators (also called as meta-atoms) Medium  (2021) Metalenz KAIST  (2022) MIT  (2021) ACS  (2019) PENN U   (2023) using DUV photolithoraphy 光刻蝕 City U  (2022) Polyu  (2020) LG  (2022) Phonearena  (2022) Laserfocusworld  (2021) Photonix  (2020) Nature  (2020) Hybrid achromatic  (2020) Harvard U , various applications Meta-Shack Hartmann   Fish Eye   To solve: Focusing efficiency ( now ~80%) How to make a bigger lens( now it's a 80 mm dia) How to lower manufacturing cost  25 Oct 2023: Canon Expo 2023 Petapixel Most promising application this moment: Microscope objective Smartphone  Semiconductor 

驚蟄，意思為二十四個節氣中的第三個節氣，意旨每年三月春雷初響，震耳欲聾的雷鳴聲震響大地，使冬眠中的生靈萬物甦醒，在驚蟄時節中，常見的天氣轉暖與頻繁雷雨，使台灣中南部的水氣變得豐沛，代表農民春耕即將開始，同時這也是水稻的插秧時期。 惊蛰时节，正值“九九艳阳天”，大地回春，长空雷鸣，草木萌发，蛰虫初醒，因而古人有“春雷响，万物长”的说法。 In the 1760s, Captain Jonathan Carver visited the Naudowessie (Dakota) and other Native American tribes and wrote that the name Worm Moon refers to a different sort of “worm”—beetle larvae—which begin to emerge from the thawing bark of trees and other winter hideouts at this time.  Worm moon is full moon in March, final moon of astronomical winter. Vernal equinox will be on 21 March in 2023

 EC stands for embedded clock Very big advantage for FPGA designers, PCB layouts  Xilinx IP core mentioned in FRAMOS Through the demo environment EasyMVC Macnica offers a versatile machine vision camera development kit. For Macnica SLVS-EC IP demos running on Xilinx devices the Macnica IMX420 FMC kit combined with the Xilinx Development kits AC701; KC705; KCU105; KCU116 can be tested.  The choice of EasyMVC combinations for Intel demos includes the sensor boards IMX420/421 or IMX530 together with the FPGA board Cyclone 10GX combined with an interface board which supports HDMI; CoaxPress; USB3; 10Gige or other.  For both the Intel and Xilinx version a free evaluation license can be requested for a three month test period. In addition, Macnica ATD Europe can provide a Xilinx Evaluation Kit Kintex UltraScale+ FPGA KCU116 to customers as well as a Macnica EasyMVC IMX420 development kit Sony website   SSS  Lattice  CertusPro NX  Macnica