Probability of new/used C9.25 being a duff one?

[Mr Spock]

Yes, Bob's Knobs. I like to collimate using a star test and fiddling with a screwdriver in the dark is almost impossible. Bob's Knobs make the whole thing easy.

[markclaire50]

49 minutes ago, Mr Spock said:

Yes, Bob's Knobs. I like to collimate using a star test and fiddling with a screwdriver in the dark is almost impossible. Bob's Knobs make the whole thing easy.

That's what I like to hear, even though I don't actually know what Bob's Knobs look like. ?

[Stu]

11 minutes ago, markclaire50 said:

That's what I like to hear, even though I don't actually know what Bob's Knobs look like. ?

Like this...

[markclaire50]

3 minutes ago, Stu said:

Like this...

Mmm. Was the inventor called Robert? 

[Highburymark]

Agree with all the advice but I think there is a variation in quality between the best SCTs and the rest - less so these days than 20 years ago perhaps but still apparent. One I had appeared to be perfectly collimated yet never provided sharp stars. A C8 Edge I had was a lot better, though couldn't compete with an excellent apo-like Mak on Moon and planets. Yet some SCTs deliver amazing images. Perhaps a degree of inconsistency is inherent to the design? 

[markclaire50]

10 minutes ago, Highburymark said:

Agree with all the advice but I think there is a variation in quality between the best SCTs and the rest - less so these days than 20 years ago perhaps but still apparent. One I had appeared to be perfectly collimated yet never provided sharp stars. A C8 Edge I had was a lot better, though couldn't compete with an excellent apo-like Mak on Moon and planets. Yet some SCTs deliver amazing images. Perhaps a degree of inconsistency is inherent to the design? 

Hi. Which sct did you have? 

[Highburymark]

I had a C6 first - maybe the problem was that it was only my second telescope, and the first was a superb Meade Maksutov, which was a hard act to follow. The optics on those Meade scopes were very good indeed, rather better than the electronics. I did a lot of research before I later bought my C8, and it was users in the US in particular who reported varying quality of SCTs - how the best were outstanding, and if you found one, you should hold onto it.