Spec
D=40 mm f=800 mm Achromatic lens (Orbys)
PVC plastic tube,stainless steel draw tube

 My telescope is made of plastic tube using the objective lens of 40 mm F20 from Orbys (2000 yen)
 The focal length is 800 mm and the eye piece is Or 6 mm so the power is 133 times .
 The inside of the tube is seal with black piled sheet to get clear image without reflection lights .
 Although I omitted the inside rings but the diameter of the tube is wide enough and the focal length is son long that I can get very clear image of the shapes of the planets .
Adding to this ,as the diameter of the objective is small , this telescope is not so sensitive to the influence of the air current . I can use it in a bud seeing condition .
So I use this scope more often than any other my telescope .