The Body Tube of this Nachet instrument is made of two tubes plus the eyepiece. There is no Field lens in this instrument.
Body components
The eyepiece is a typical Huygenian optic consisting of two lenses with an aperture in between.
Top lens dia=15mm, f=30mm.
Bottom lens dia=20mm, f=45mm.
Top lens dia=15mm, f=30mm.
Bottom lens dia=20mm, f=45mm.
There are no objectives with this instrument.
Eyepiece
Objective mount