Only purchase the Meade 933, 45 Degree Erecting Prism if you want to use your ETX for terrestrial viewing. It doesn't really have a uselful astronomical application and tends only to diminish the quality of the object viewed in space. You don't necessarily need this for terrestrial viewing either unless you desire to see the object in its correct orientation, which is what this item is designed for. Does the job nicely in this respect. Recommended for terresrtrial viewing only.
Good for spotting use- but not for astronomy.
2000-12-10
Erecting prisms like this Meade unit are a great help for terrestrial use, but don't try to use it for astronomical viewing. The multiple reflecting surfaces in the prism result in multiple ghost images when trying to view stars and other dim astronomical objects. If you buy a Meade ETX with the idea of using it for nature viewing you'll find it handy.
