A slide rule to conquer the Moon


In the June 2013 issue of the french magazine "Ciel & Espace" (Sky and Space), there is a 4-pages article about : "A slide rule to conquer the Moon"


On 13 April 1970 at the accident of Apollo 13, the slide rule is omnipresent on the ship and in control rooms. The small hinged bar invented three centuries earlier will play a central role in the rescue (...)

Ironically, the rescue of Apollo 13 marks the swan song of this tool. In 1972, the first scientific calculator, the HP35, arrives on the market and the men of the NASA will use it more and more as it cost will go down.

But the slide rule is not quite a dusty memory today : One man of the NASA continues to resist. (...) Evan Horowittz (...) does not hesitate to use his slide rule because it has one unsurpassed quality : It requires to consider the variables that are manipulated and prevents the illusions about the accuracy of the numbers that appear on the screen.

"A good approximate answer will always be better than a false result, even if it is with 10 decimal places", he says philosophically.


humm : Not sure that " swan song " means something in english. In french it means "the beginning of the end" ...

Edited: 2 June 2013, 4:27 p.m.


humm : Not sure that " swan song " means something in english. In french it means "the beginning of the end" ...

It means the same in English.

- Pauli


Any english speaker will understand the phrase "Swan Song"....just like you interpreted it.


Know what? Frenches have a odd habit, they speak French :)

So, if you ask a French adult about a song with the word "swan" there is a good chance that he will think about a song from 1976 "Du Côté De Chez Swann", which have nothing to do with the subject.

you will have to translate to "Chant du cygne" in to be understood by everyone, and the signification is the same.


It seems that "chant du cygne" and "swan song" came from the same ancient greek origin ...

But i'm afraid that the conquest of the Moon by men was 'le chant du cygne' of the human exploration of planets.

These pionneers have done fifty years ago with slide rules, what we are unable to do nowadays with super-computers. 'Chapeau bas messieurs !' (in french in the text ;)

Edited: 3 June 2013, 8:16 a.m.


...and then spread throughout the western world:

Cantus cygni
Canto del cigno
Canto do cisne
Canto del cisne
Chant du cygne
Swan song


Sorry Saxon chaps but I´m afraid you acquired this idiom from the Normands :-) The beauty of English is that it has two stems for its vocabulary, Latin being one of them.

Edited: 3 June 2013, 2:48 p.m.



Never thought anyone would mention a song by Francophone singer Dave (of Dutch origin) here!! Big fan here. I am waiting for the DVD release of a movie where Dave is kidnapped by a family whose dying mother had a wish to hear Dave sign to her in person!!!!


PS: Dave's real name is Wouter Otto Levenbach. He has studied law!!

Edited: 4 June 2013, 3:47 a.m.


For Namir, special and completely off topic dedication ;)


Very french seventies :D Not sure you can access out of France but there is on the site dozens of videos and interviews of Dave

But the swann of dave is more a (very) distant reference to the writer Marcel Proust than to a 'cygne'

The INA site (french TV archive) includes some funny things about calculators :


look at 1mn30. French TV news en 1977 : It was about a plan to produce french small computers... It resulted not in Mega nor TeraFlop but only a total flop ;)

Edited: 4 June 2013, 5:08 p.m.


Thanks Gilles for the video of Dave. I was singing along with it. He was quite popular when I lived in Paris in 1978. It was nice to be back two weeks ago. The weather was a bit rainy. I did go to the Louvre museum to see the Code of Hammurabi tablet which I had thought was in the British museum (until I went there in 2010). It was a moving experience for me to see the early laws of civilization. The writing was top to bottom!!

The video bit about calculators was also cool.



A good approximate answer will always be better than a false result, even if it is with 10 decimal places

integral(SIN(X),X,0,2*pi) = -1.93772545304 (???)
comes to my mind.




I am resisting as well. If the calculation is too lengthy for the slide rule I'm relying on my HP15C

Edited: 3 June 2013, 2:37 p.m.

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