Re: LX200 first light observation report

From: md (not)
Date: 12/22/04 

Date: Wed, 22 Dec 2004 21:17:43 +0100

"Roger Hamlett" <rogerspamignored@ttelmah.demon.co.uk> wrote in message
news:iZbyd.391$3D4.50@newsfe6-gui.ntli.net...
>
> "md" <not given to avoid spam> wrote in message
> news:41c8b8b5$0$147$e4fe514c@news.xs4all.nl...
> >
> > "Craig M. Bobchin" <CBobchin@csi.com> wrote in message
> > news:MPG.1c3113324f63055998969b@news.la.sbcglobal.net...
> > > The LX-200 is an F10, while the ETX is an F14. So fl is the wrong term
> .
> > > I should have used focal ratio. The ETX has a smaller CO than the
> LX200.
> >
> > agreed, but assuming CO is "central obstruction", the LX200 10" has
> > a relative smaller CO than
> > the ETX
> Er. No.
> The ETX CO, is 31% by diameter. The LX CO, is 37%. The slower focal ratio
> of the Mak, allows a smaller CO. Check the Meade specification sheets for
> the scopes. The ETX CO, is quoted as 9.4% by area, while the LX200 is
> quoted as 13.7%.

oops, you're right, I mixed up those two numbers

Quantcast