p?

[Dave Lloyd]

Dead simple question folks. Does the p that follows the objective size, seemingly only on reflectors refer to a parabolic mirror?

[RikM]

Yes

[ronin]

Yes.

Only therefore applicable to a mirror.

[Dave Lloyd]

Thanx guys

[MattJenko]

what about the X in the skyliner 250?

[ronin]

X = Unknown.

No one has any idea why they included an X, but it looks impressive and makes the overall cost £30 more then the non-X variant.

[Fozzie]

I thought I had read somewhere that the "x" stood for Pyrex mirrors, as in made out of, made from, blah blah..???? The awards, sure I read that somewhere, but then I've been known to be way off the mark sooooooooo many times before.

[RikM]

Yes, you are right. PX is parabolic Pyrex. In the UK they have only had the 250PX but there other sizes have been listed on European dealers websites. It is supposed to impart better thermal stability and faster cool down. I don't know how much difference it makes, but the 250PX is a cracking telescope