These are the most frequently used words in this book.
according
ad
ancient
another
astronomers
astronomical
babylonian
bc
between
calendar
called
century
christian
clock
cycle
date
day
different
easter
egyptian
end
equation
equinox
era
even
events
february
first
four
full
give
given
golden
great
greek
gregorian
hours
however
january
jewish
julian
known
last
later
leap
length
letter
lunar
lunation
march
may
mean
method
month
moon
must
names
new
number
old
part
people
period
place
planets
point
position
possible
reform
roman
rule
seasons
second
see
set
seven
several
should
since
solar
solstice
sometimes
stars
start
still
sun
sunday
system
ta
table
three
thus
time
two
use
used
value
week
world
year