Celestron rank amongst my favourite telescope suppliers, they are consistant in their quality and with the exception of the odd eyepiece here or there I've not come accross a product that I haven't been impressed with.
So when I was considering buying my first Schmidt Cassegrain I immediately thought of Celestron and their 127XLT. I already had the omni XLT 120 refractor so could attest to the high level of detail the starbright XLT lense coatings allow you to pluck out of faint galaxies as well as bright planets.
For those who are unfamiliar, Schmidt Cassegrains belong to a family of telescopes called catadioptrics, these can be thought of as a cross between a refractor and a reflector in that they use both lenses and mirrors in their design.
The setup of said lenses and mirrors enables the OTA (telescope tube) to be kept very short, the payoff of having such portability is that a Schmidt Cassegrain will offer slightly dimmer views than an equivelantly sized refractor or reflector telescope and they also cost a little more (the omni 127 costs around £520).
The tube is wonderfully compact it's only a foot in length but offers a focal length of 1250mm, it's light to, at only 18kg. Portability is definately a strong point for this scope but portability is nothing without performance.
When compared to my 120mm refractor the views are ever so slightly dimmer despite the schmidt cassegrains 7 extra millimetres but when compared to other schmidt cassegrains of similar aperture the Celestron offers pleasingly sharp views of the planets and some of the brighter deep space objects.
There is no doubt that this telescopes main appeal lies in it's portability as for the same price you could get a more powerful newtonian or refractor, but if space is at a premium or you've only got a small car to get to darker skies then Celestrons omni is one of the better cassegrains available in the £500 price range.
To conclude the Celestron omni xlt 127 is a great performer amongst it's catadioptric cousins, it's not only portable and easy to use but it offers great views for a schmidt cassegrain and comes mounted on a cg-4 german equatorial mount which is a very sturdy and reliable mount.
Also at f10 this scope is suitable for astrophotography, I've got some good shots with it over the years (although it's not my main telescope for astrophotography).