At the end of the summer of 2004, Celestron introduced a new NexStar GT model employing an 80mm f/11 refractor - the NexStar 80 GTL.  The "L" after the GT indicates the longer optical tube when compared to the NexStar 80 GT.  This model seems to be a limited offering rather than a new addition to the GT model line.

The general description of GT mount as found in The NexStar User's Guide applies equally to this scope.

The longer optical tube results in a more traditional achromatic refractor yielding better color correction than short tube refractors like the NexStar 80 GT.  Better color correction allows for much improved high-magnification views of brighter objects such as the Moon, planets and brighter double stars.  The results are sharp views of the planets and lunar craters and splitting double-stars as close as 2 arcseconds.

The longer optical tube is substantially heavier than the other optical tubes in the GT series.  The added weight results in a bit of shaking when focusing, but with a little care this is manageable. The longer tube also results in more restriction when pointing towards the zenith.  Follow the direction on page 93 of the book to set correct Slew Limits to prevent the optical tube from contacting the tripod.

Celestron has posted a list of Frequently Asked Questions for this model here.