I recently added a tutorial teaching how to estimate the moon phase for any date.
It’s an unusual feat that you rarely see, so I figured it would be fun to share. When performing it, people can verify your estimate of the moon’s phase by entering the given date in Wolfram|Alpha, so as long as someone in your audience has a mobile device connected to the Internet, you’re set!
If you already do the day of the week for any date feat, you’ll find this to be easy.
Kinma,
That’s a great approach, but ONLY for the years 2000-2009. It will be accurate to within about a day for those particular years, and ONLY with those particular years.
There’s an extension to that system at the following link, but the error increases to 2 days for the years 2010-2019.
http://www.stargazing.net/mas/moon4.htm
In John Conway’s system, which I teach in detail at the link in the first post in this thread, the only time the error gets to 2 days off is in the middle of January. Other than that, it’s only 1 day off max for any year from 1900-2099. I also teach how to adapt it for other Gregorian centuries.
A couple of good sites for checking the accuracy of the calculations include:
http://cycletourist.com/moon/
moon phase for today - Wolfram|Alpha (Wolfram|Alpha won’t give the age in days, but does give the phase and a picture. Enter any date, and the moon phase will be included in the info about that date.)
Thanks, that’s a very interesting idea. 