Once every 29 d. 12 h. 44 min.
What is the period from one new moon to another called?
It is called a Lunar month.
Are the lunar months all of the same length?
Yes; they are all of the same length.
Is there any other kind of month?
Yes; the Calendar month, as it stands in almanacs.
How many calendar months in a year?
There are twelve calendar months in a year.
Are the calendar months all of the same length?