Corrector Lens Coatings

Hello all:

What is the difference between Starbright coatings and XLT coatings on the corrector lens of SCT's?

Rey

Starbright is a single-layer Magnesium Fluoride coating on
both sides of the corrector. Its a sort of pale blue color.
XLT is a multi-layer coating and is a very deep blue color.
The XLT models also use a cleared glass called BK7 for the
corrector, whereas non-XLT use a slightly greenish plate
or float type of glass.

There is some info here, though not sure I completely
believe their numbers:
http://www.celestron.com/c2/technology_view.php?TechnologyID=2#measurements

The short version is that the XLT corrector lens uses a different glass and mixure of elements in their coating.

The long version is here:

http://www.celestron.com/c2/technology_view.php?TechnologyID=2#overview

Thanks Dennis and John for your links.

Rey