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目前顯示的是 5月, 2022的文章

IOptron HEM27 hybrid harmonic mount

Finally, a harmonic mount from iOptron Load capacity 13.5 kg without counterweight  RA motor: harmonic drive type 17 DEC motor: stepper worm motor RMB 12980, 19980 ( with EC encoder) initial findings is that the altitude base has a upper COG closer to the tripod z axis, thus will be more stable than zwo AM5. This is similar to CRUX design concept Bilibili skygazerslounge

Sagittarius A* blackhole

  Role of numpy in EHT project  SMILI   SCIPY   numFOCUS   CLEAN CHIRP .  ML PRIMO IEEE Spectrum Supercomputer  

ZPM pid controlled espresso machine

Igor Zamlinsky (left) and Gleb Polyakov (right), both Russian immigrants who grew up in Atlanta. Igor is a mechanical engineering student at Virginia Tech and Gleb is a student at George Tech. kickstarter page features: redesigned thermoblock PID controlled temperature and pressure, pre-infusion, shot-time settings all these parameters are user programmable Arduino Mega controlled Vimeo Kickstarted in 2012, raised 16 times more of its target, promised to deliver the machine in 2 years time.  Unable to complete the project, and sold the IPs to John Buckman , who founded the Decent Espresso machine DE1  Home barista dtusciencepark . Why crowdfunded hardware projects fail .... working with pressurized, boiling water can be a dangerous game for even the most experienced engineers, and Polyakov and Zamlinsky were just beginning their careers. Early prototypes of the machine had water “spurt[ing] halfway across the room”, and later ones sported deflecting panels under high pressur...

Open AI DALL E2

Can create or edit by natural language description, eg An astronaut riding in the desert  Dall.E has now evolved into DALL E2

solar image 19 may 2022

  sunspots AR13014 is clearly visible SOHO of NASA SDO  satellite of NASA  GONG .  Solarchatforum

第5波後疫情

  17 may 2022 「新旺會桌球雀會」、「星月樓」群組部分個案的全基因分析證實屬BA.2.2,為本地流行的Omicron個案,但均與元朗「牡丹金閣尚品火鍋涮涮鍋」個案的基因不一樣,即代表三個群組沒有關連。 歐家榮又說,早前曾公布「星月樓」一名員工居西環邨西苑臺,當局日前於西環邨西苑臺的圍封強檢行動中,發現23宗個案涉不同單位,均於5月7日前發病,故相信西苑臺的傳播在5月7日前已發生。 他續指,而「星月樓」群組於5月8日發生,當中有3名最早發病的人士均於5月8日出現病徵,包括該名居西環邨西苑臺的員工。當局不排除他就是引致「星月樓」群組爆發出現的人士,相信源頭亦是在西苑臺,但未能完全確認是該名員工染疫後上班而引致群組爆發。 歐家榮補充,病毒基因排序顯示星月樓、新旺會及元朗牡丹金閣群組均涉本地流行的Omicron BA.2.2亞型,惟有少許差異,相信群組間無關聯。他又稱,新旺會兩名近日抵港顧客染疫,病毒基因排序證實所帶病毒屬本地流行病毒株,改列本地感染。 Hket

Viltrox EF-NEX IV adapter teardown

J2 connector ( towards camera side) : pin 1 (lens_gnd) and 3 (logic_gnd) are connected    Under Linux, it is recognised as USB mass storage  PCB version: EF-NEXIV_V2.3 date code: 20201223 U3: The MCU is a STM32F103T8U6  , cost ~USD 2 U1: W25Q?? serial flash  ? There are 4 through holes labelled as G D C V, which is deduced to be ST-Link port G: gnd. connect to pin 1 of J2 V: Vcc. connect to pin 5 of J2 D: SIO, serial data. TBD  C: CLK, serial clock. TBD Estimate BOM cost is USD 10 or less Viltrox EF-NEX II

venus moon occultation 2022

all time is in HKT happens on 27 may 2022 day time nao venus magnitude -4, a small telescope is needed Lunar occultation   in-the-sky astronomy society hk

Queen's speech 2022 on crypto

  Financial Services and Markets Bill A  publication  released by the  UK  Prime Minister’s office stated that the Financial Services and Markets Bill seeks to cut red tape in the financial sector to make the UK an even more attractive place to invest and do business while making sure that high standards are maintained. The Bill further proposes to harness the opportunities of innovative technologies in  financial services , including supporting the safe adoption of cryptocurrencies and resilient outsourcing to technology providers. Economic Crime and Corporate Transparency Bill Another Bill introduced by the government - The Economic Crime and Corporate Transparency Bill – will create powers to more quickly and easily seize and recover crypto assets, which are the principal medium used for ransomware. The creation of a civil forfeiture power will mitigate the risk posed by those who cannot be criminally prosecuted but use their funds to further criminality...

crypto's fall in 10 charts

 By Connie Lin <https://www.fastcompany.com/user/connielin> As the cryptocurrency market burns through its worst crash in years, Twitter is ablaze with charts streaked in red, suggesting that a new crypto winter is here. The great downturn came during a bearish week for Wall Street stocks, a correlation that didn’t escape notice: Despite working through what must be the most horrifying fire drill in recent memory, some traders still tried to joke about the frazzled days spent glued to their computer screens, watching assets fall through the floor. Others found a different type of humor in the madness. If you were wondering: The mystery chart turned out to be the price of Luna coin, the cryptocurrency token meant to buoy the floundering Terra USD stablecoin—which was designed to stay consistently valued at $1 but sank to under 40 cents in recent days. Luna, meanwhile, dropped from nearly $120 in early April to roughly 1 cent Thursday—an event so catastrophic that its developer...

crypto's fall in 3 charts

    * Bitcoin is down 40% to start the year as investors sell risk assets.     * Stifel's Barry Bannister is warning of further downside is ahead.   * He said bitcoin could fall as low as $15,000, downside of 47% from     current levels. After its rally in March back toward its January levels, bitcoin <https://markets.businessinsider.com/currencies/btc-usd> is again biting the dust in 2022. Bitcoin is down 40% on the year after falling more than 28% since May 4 alone. Much of the broader crypto world has followed suit. According to Stifel 's Chief US Equity Strategist Barry Bannister , the price of the biggest cryptocurrency in the world by market cap Market capitalization tells you how much a company is worth, and whether buying its stock suits your overall investing strategy Market capitalization is the total worth of a company's outstanding stock. It indicates a company's size and investment value in terms of shares. still has further dow...

DEIMOS

  David Hilyard and the DEIMOS optics: The spectrograph   Control software   Keck observatory  

Gypsum and Calcite collection in Science Museum

 When I visited Science Museum, and come across the earth science gallery, I found some interesting mineral rock samples   This rock is labelled as calcite, 方解石, application: calcium supplements   This is labelled as gypsum石膏, application: construction AFAIK, calcite ( calcium carbonate crystal)is well known for its birefringence property. However this Science Museum sample is not transparent at all.   Whereas gypsum (calcium sulphate crystal) is normally known to be non-transparent. This gallery sample is a special type also named as selenite 透石膏, and usually tabular or prismatic structure  btw, it would be a waste to use it for plaster or fertilizer, if this sample has such excellent optical property.

How to repolish the lens AR coating

 From David Hilyard ( optician in the past) Steve Grey It's been my experience that any kind of solution either doesn't work in stripping the coating or does work, and also attacks the surface under it. I doubt alcohol would have any affect. I've stripped with acids on known substrate material that wouldn't be affected.  Polishing is the safest but most involved. You'd need a polishing machine, spherometer, radius bench, pitch lap, lap tool, polishing compound, interferometer and appropriate transmission sphere for monitoring figure and radius. Inpection lamp and loupe. There's an art to removing coating and maintaining the radius and figure. And you don't want the thickness to change much. It's a fun thing, if you have the stuff.

Amateur astronomers discovered impact on Jupiter

 In 2009   Anthony Wesley and Phil Miles, and Christopher Go independently discovered the impact. Anthony used his homemade newtonian telescope to observe the moment of impact on Jupiter Anthony's equipment: 14.5" mirror f/8 Focal length: 1.8m Queensland, Australia Interview   10 questions Archive Cloudynights   CN2