# Taipei.py 3 月聚會

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clbc 四樓

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## Details

The entrance is an apartment door (with "CLBC" bell label) https://goo.gl/maps/eXHudbMx57u.

Predicting the movement of the sun, moon, and planets in the sky used to be a high-art, practiced by wizards and priests. Now anybody can do it with a few lines of python!

The package Skyfield (http://rhodesmill.org/skyfield/) is the pythonic end result of a huge amount of work, math, coding, and long computations.It puts the heavens at your fingertips, by loading and accessing the JPL ephemerides (https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris) for you and then giving you all the necessary math, interpolation, spherical trigonometry, light speed propagation and unit conversion as simple python methods.

I'll show you how to find out where the planets are, were, or will be, when and where the sun will rise and set and how to optimize the direction of your solar panels - even predict eclipses!

Skyfield can also interpret standard two-line elements (https://en.wikipedia.org/wiki/Two-line_element_set) (TLEs) of satellites, so we can calculate when and where various satellites will pass overhead.

I'll use python 2 to teach, and we'll need numpy, matplotlib, and a command line terminal. Since time is limited please install Skyfield ahead of time, and just test the example at the top of the home page. We'll compare our results to Stellarium (http://www.stellarium.org/) and In-The-Sky (https://in-the-sky.org/) the off-line and on-line resources I recommend.

Skyfield 套裝軟體（http://rhodesmill.org/skyfield/）是一個匯集巨量工作、數學、程式，以及長時運算的 pythonic 成果。它提供你簡單的 Python 方法來做所有必要的數學運算，如內插、球面三角學、光速傳播，以及單位間的轉換。（藉著存取 JPL 星歷表（https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris） ;

Skyfield 也可以解譯衛星「兩行軌道要素」（Two Line Elements 或 TLEs，https://en.wikipedia.org/wiki/Two-line_element_set），因此我們可以計算出各種衛星會在何時何地的上方經過。 ;

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It will introduce how to implement the CSP (Communicating Sequential Processes) in Python with common libraries.

CSP（communicating sequential processes）是一個著名的並行系統（concurrent systems）數學理論 [1]，並獲得 Go lang 採用作為其並行設計的基礎 [2]。其優點是相較於傳統的多執行緒設計來說較為簡單 [3]，依此理論可以設計出更好維護的並行程式。

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