|
Post by plyscope on May 26, 2011 17:34:19 GMT -5
The cell holding the lens elements is 148mm diameter.
The 168mm flange is the larger part around the cell that has the push/pull threads to mount the cell to the scope.
Hope this helps.
Andy
|
|
|
Post by steveg on May 29, 2011 8:57:57 GMT -5
Thanks that is what I was looking for.
|
|
|
Post by plyscope on Sept 20, 2011 6:49:33 GMT -5
I have recently weighed this lens in cell and it is 2.69 kg.
For comparison a 5" f15 D & G lens in cell is 1.88 kg. A 6" f15 D & G lens in cell is 2.49 kg.
The R30 glass is obviously thicker or simply more dense than standard achro glass. This was recently commented on in Mikey Cee's thread on his new 10" R30.
Andy
|
|
|
Post by Mike on Sept 20, 2011 21:26:50 GMT -5
Your observation is correct Andy as your weight data proves. R30 glass is indeed heavier (denser). The higher the index the denser the material. However, the lens is not necessarily thicker, in fact quite the opposite. High index glass allows a flatter curve and thinner lens to achieve the same results as a steep curved, thicker lens made of standard crown or flint. On the other hand, the lens has to be a certain thickness to mount well inside the cell and not move. Bend light faster and good things can happen with the right design.
Mike
|
|