WARNING: Please simply do NOT do it, since it's extremely dangerous even if you follow the following exactly and do it correctly.
Some pictures about the setup:-
Very roughly put it in a 70mm lens cell:-
Very dirty hack to put the lens cell on my Borg 45ED custom tube using duct tape:-
This is a special observation conducted in my friend's home, we use a 70mm C-ERF and PST etalon, BF10 to make a bigger scope setup, the result is very satisfactory:
Borg 45ED custom made OTA, duct tape hack with 70mm lens with C-ERF in cell, a chain of Borg adapters to make up the length and a BF10.
An image captured by this setup... too bad that the image scale should be pumped up with the larger aperture, but the sun is too low and even blocked after this image: