These are the most frequently used words in this book.
1955
air
aperture
astronomical
astronomy
axis
axle
building
built
camera
cm
computer
courtesy
described
design
designed
dover
drive
end
example
eyepiece
field
fig
figure
finder
first
focal
ft
gear
glass
henry
history
however
image
instrument
king
large
larger
length
lens
lenses
light
long
main
making
materials
may
metal
mirror
mount
mounted
move
must
near
newtonian
observations
observatory
observer
observing
often
optical
optics
order
parts
path
photo
plate
point
position
primary
problem
publications
radio
refractor
required
satellites
second
secondary
see
seen
several
shown
since
sky
small
solar
stars
structure
support
surface
system
telescope
thus
time
tube
two
use
used
view
work