I was observing the moon with my home-built 6-inch reflector, using an Erfle eyepiece and a Goodwin Barlow lens which gave a magnification of 200 times and a 20-minute field.
(a Goodwin Barlow lens; gave; a magnification of 200 times and a 20-minute field) (I; was observing; the moon) Context(I was observing,List([0, 15))):(I; was observing the moon using; an Erfle eyepiece and a Goodwin Barlow lens)
I was observing,List([0, 15))
a Goodwin Barlow lens I I
gave was observing was observing the moon using
a magnification of 200 times and a 20-minute field
the moon
an Erfle eyepiece and a Goodwin Barlow lens