Hi,
Hope someone can help me out with this question and if it's a daft one, I apologise

I have just bought a 26" Charles Beseler projection lens and wanted to know if it says 26" does that mean it's a 660mm lens. Also how will I figure out what aperture it is and the image circle.

I have tried to google the answers I need but I can't find what I am looking for.

I paid £120 for it and I'm hoping I didn't pay to much for it as I couldn't find any similar lens for sale at the time.