I know a lot of you include sun/moon ephemeris on your sites.
An interesting thing is that most of the sites I look at which give Moon age in days are wrong, and usually wrong by the same amount +0.8 days.
It is not a difficult thing to calculate - it is just the amount of time since the last New Moon. If you want to check it:
https://svs.gsfc.nasa.gov/4442Has anybody else noticed this? And does it mean that there is an algorithm out there in common usage which is wrong?
Or am I missing something? (Highly likely!)
http://moonappreciationsociety.com/Meteo/VillarPerosa/index.php
