A buddy in when I was in my 20s told me about grinding his own concave lens. Relatively simple pattern using gringing compound. I forget the details. He said it worked pretty well but he no longer had it. He did bring over an inexpensive 2 inch refractor telescope, had a crude hand operated tracking mechanism that was better then nothing. I was amazed that you could see Jupiter's red spot (not red in this scope) and some of its moons as well as Saturn's rings.

__________________
1986 300SDL, 362K
1984 300D, 138K