Ozone sensor https://www.dfrobot.com/product-2005.html?tracking=60f546f8002be

Found on https://jao.io/blog/in-no-particular-order.html

Der Energieticker NÖ zeigt live die Energieerzeugung aus erneuerbaren Energien im Vergleich zum Stromverbrauch in Niederösterreich. Man sieht, zu welchen Zeiten NÖ mehr erneuerbaren Strom erzeugt, als im Land verbraucht wird.

Interesting blog written in org-mode, using https://github.com/bastibe/org-static-blog, written by Bastian Bechtold https://bastibe.de/
Some highlights:
https://jao.io/blog/2020-02-26-literate-programming.html literate programming
https://jao.io/blog/2020-02-23-signel.html, a barebones signal chat on top of signal-cli, written in literate style
https://jao.io/blog/2006-03-17-programmers-go-bananas.html category theory
https://jao.io/blog/2020-05-01-dancers-at-the-end-of-time.html sounds like an interesting book.
https://jao.io/blog/2006-07-06-geometrically-speaking.html geometric proofs, Kindergarten Quantum Mechanics
https://jao.io/blog/2020-05-04-observatory.html Mozilla Observatory to check a website's security
https://jao.io/blog/2022-06-19-simple-note-taking.html simple note taking

The Theoretical Physics Reference is an attempt to derive all theoretical physics equations (that are ever needed for applications) from the general and special relativity and the standard model of particle physics.

The goals are:

   All calculations are very explicit, with no intermediate steps left out.
   Start from the most general (and correct) physical theories (general relativity or standard model) and derive the specialized equations from them (e.g. the Schrödinger equation).
   Math is developed in the math section (not in the physics section).
   Theory should be presented as short and as explicitly as possible. Then there should be arbitrary number of examples, to show how the theory is used.
   There should be just one notation used throughout the book.
   It should serve as a reference to any physics equation (exact derivation where it comes from) and the reader should be able to understand how things work from this book, and be ready to understand specialized literature.

Galileo/GPS/BeiDou/Glonass open source monitor.
Found via https://hackaday.com/2019/09/24/tracking-the-satellites-that-keep-us-on-track-monitoring-gps-galileo-beidou-and-glonass/
The source code can be found on https://github.com/berthubert/galmon

See also the articles https://berthub.eu/articles/posts/galmon-project/ and https://berthub.eu/articles/posts/improved-galileo-fix-time/
Read https://berthub.eu/articles/posts/galileos-eccentric-satellites/, all formulas are approximations.

Collection of interesting papers, including the famous MIT HAKMEM http://home.pipeline.com/~hbaker1/hakmem/hakmem.html
Lisp, garbage collection, modular arithmetic and more.

An Elementary Primer on Elementary Particles and their Interactions

Apart from the blog, there are technical notes https://www.johndcook.com/blog/writing/ and on-line calculators https://www.johndcook.com/blog/online-calculators/
As an example, see Camp-Paulson normal approximation to the binomial distribution https://www.johndcook.com/blog/camp_paulson/
The articles https://www.johndcook.com/blog/2024/04/01/more-laguerre-images/ and
https://www.johndcook.com/blog/2024/03/22/laguerres-root-finding-method/ demonstrate the basins of attraction for Laguerre's root-finding method.
https://www.johndcook.com/blog/2018/11/24/spheroid-distance/ should be useful for azel.
https://www.johndcook.com/blog/2020/02/08/arenstorf-orbit/ shows a periodic solution to the restricted 3-body problem.
https://www.johndcook.com/blog/2022/11/14/simultaneous-root-finding/ describes the Durand-Kerner polynomial root finding method.
https://www.johndcook.com/blog/2022/11/01/kepler-newton/ discusses solving Kepler's equation

TODO: https://www.johndcook.com/blog/2022/10/30/arctan-k-tan-t/ states "This plot looks similar to the plot of true anomaly for a highly elliptical orbit. I’m sure they’re related, but I haven’t worked out exactly how."

https://www.johndcook.com/blog/2022/10/21/math-origins/ explains V.I. Arnolds comment
"All mathematics is divided into three parts: cryptography (paid for by CIA, KGB and the like), hydrodynamics (supported by manufacturers of atomic submarines), and celestial mechanics (financed by military and other institutions dealing with missiles, such as NASA)."

https://www.johndcook.com/blog/2018/09/24/riemann-hypothesis-the-fine-structure-constant-and-the-todd-function/ is about  Sir Michael Atiyah's incorrect proof of Riemann's hypothesis, the article https://rjlipton.com/2018/09/26/reading-into-atiyahs-proof/ is an interesting read. (I had bookmarked this entry on Wed Sep 26 15:51:47 2018 and put it here 2024-04-03.)

The article https://www.johndcook.com/non_central_chi_square.pdf sounds interesting:
John D. Cook Upper bounds on non-central chi-squared tails and truncated normal moments (2010). UT MD Anderson Cancer Center Department of Biostatistics Working Paper Series. Working Paper 62.
Abstract. We show that moments of the truncated normal distribution provide upper bounds on the tails of the non-central chi-squared distribution, then develop upper bounds for the former.

Information about visual satellite observation.