What f/ number is my Ensinor 500mm mirror lens? It says 1:8?

[RedSpectrumPictures]

I just want a confirmation from someone that knows more about lenses than me. So the 1:8 means the f/ number is f/8?

Thanks in advance for any answers

 

[David G. Smith]

I just want a confirmation from someone that knows more about lenses than me. So the 1:8 means the f/ number is f/8?

Thanks in advance for any answers

Yes.