Ted Shoemaker wrote:
The eyepieces have outer diameter of 25 mm. They go into a piece
called the "diagonal" which has an inner diameter of 32 mm. Even with
the adjusting screws tightened as far as possible, they don't fit. Do
I need an adapter? Or do I need different eyepieces? In either case,
where do I get them?

You need a 1.25-0.965 inch adapter. Orion sells them, among others.

http://www.telescope.com/

Brian Tung
The Astronomy Corner at http://astro.isi.edu/
Unofficial C5+ Home Page at http://astro.isi.edu/c5plus/
The PleiadAtlas Home Page at http://astro.isi.edu/pleiadatlas/
My Own Personal FAQ (SAA) at http://astro.isi.edu/reference/faq.txt