[gregbradley]

The Megrez 90 also uses FPL-53 glass in its objective, where the Megrez 110 uses FPL-51. Another reason why color correction may not be as good using the 110...

Whilst I have no specific knowledge of these 2 scopes and which is better than the other the fact of FPL51 does not necessarily mean lesser colour correction.

Roland Christen has stated several times in the Yahoo refractors group that it is the mating element that determines colour correction not the material of the main lens.

So knowing what one element is made of is something scope manufacturers play on and they do not say what the mating elements are made of.

For example the Tak FS series has a mating element which is cheaper than the superior mating element of the Tak FC series which they changed apparently for cost saving reasons. But both are fluorite doublets.

The TEC 160mm ED which gets fabulous reviews uses FPL51 as the main element in its triplet.

Its a bit like the concentration on megapixels in marketing of cameras - it isn't necessarily the factor that will make the best image between 2 competing cameras of different megapixels.

It would be safer to assume (and again a generality here is only a practical thing not a rule) that a well made triplet will outperform a well made doublet.

An alternative (perhaps more expensive though) is the WO FLT110 with a TMB triplet lens. If the Megrez 90 is a doublet than I would check out the FLT110 as a triplet generally speaking will outperform a doublet for colour correction. TMB also have an excellent reputation.

Greg.