Moon info

[Buchanan]

I am a clock maker and have a commission to build an astronomical clock.
I am looking for a person who has an in depth knowledge of the moons anomalies to discuss the problems related to depicting the moons rise and set on a clock dial. You can see progress on the clock athttp://www.my-time-machines.net/astro_index.htm Can anybody help?
Regards
Deryck

[pluto]

I'm sorry that I cannot help but I wanted to say WOW :eyepop:
What an amazing and beautiful machine you're building!

[Wavytone]

Deryck you're a very brave man to try this.

If you can get access to an iPhone I'd suggest download the Emerald Chronometer app and have a look at the "Mauna Kea" face of this (digital) clock for inspiration - it shows moonrise and set, sunrise/set and much more.

The only way to do this IMHO is to have hands where each hand can move independently of the others and have a microprocessor work out where each hand should point, and use stepper motors or shaft encoders to position each hand accordingly - without using old-school geartrains.

[Buchanan]

Hugh, thanks for the compliments. Wavytone. Thanks for your reply. I am stuck with mechanical, as the rest of the clock is also mechanical.I have built a CNC mill, so understand the easy way, but the chalange is to do it mechanically.

[Wavytone]

Ok ... well take a very deep breath.

Do you know the basic maths - see for example the texts by Jan Meeus or Peter Duffet-Smith ? Even just a first order solution is going to be hard for you as it involves trigonometric series and you won't do that mechanically. I used to calculate ephemerides using these methods 30 years ago.

What accuracy do you require ?

The method used by Duffet-Smith will get you to +/- 1 minute. To do better you have to use Meeus' method and allow for parallax (ie an observer at the surface, not centre of the earth) and atmospheric refraction - both of which are not trivial.

This is the point of the Emerald Chronometer which uses the observers location and in addition it syncs to atomic time standards within milliseconds.

But yes I agree a fine mechanical clock is a beautiful thing and I'd love to own one, having been to Greenwich in the days when they had a full exhibit of clocks (long gone now tanks to bean counters).

PPS there is a specialist fine woodwork gallery in Leura which has some superb handmade wooden clocks - upwards of $10k apiece - if you're into this might be worthwhile displaying there.

[JethroB76]

Holy moly

[silv]

Hey Deryck,

fascinating work, inspiring project! To think that you are working on this particular clock in the tradition of historical clock makers... and that you are facing the same question about lunar anomalies that astronomical clock makers faced since the earliest days... and to imagine how they, back then, conducted their research and contacted astronomers...

I'm not the person you're looking for - but I used to be a scientific librarian and still have some skills to find at least preliminary literature for a given question.

This article (http://astrohahn-koeln.de/SuW-Artikel.pdf), especially page 3 [or 72 in it's original publication], describes historical and current algorithms for machining lunar anomalies into astronomical clocks.
While this article is in German and not so useful, probably, it's author is a physicist, author of astronomical books and newspaper articles -
AND he is a translator of articles and books. So it's safe to assume you can converse with him in English, directly.
In the right bottom corner, click on "Kontakt" (http://www.astrohahn-koeln.de/buchliste.html) under his picture to email him.

The PDF linked to above is about the astronomical clock that was built in Germany by Hans Scheurenbrand in the early 2000s.
Hans past away in November 2015 so we're a little too late to contact him directly. He wrote a book (https://www.amazon.de/Astrolabium-Kalenderuhr-Glockenspiel-Festo-Harmonices/dp/3440103293) in German on his clock work - probably available through international lending at a scientific library in Australia. (Note that Hermann-Michael Hahn is co-author on the book, too.)

Lastly, if you would like to open a thread on an astronomy forum with a much bigger audience, try this http://www.cloudynights.com

Totally intriguing web page, too!

Cheers Annette, now living in Rostock, where the astronomical clock (http://www.astronomischeuhr.de/en/files/vorwort.htm) in St Mary's is being wound up every day since 1472...