How Precise Can the Meade ETX Autostar Observation System Be?
The Meade Autostar is designed to compensate for a lot of user errors. If your time, location, and alignment (Polar alignment, star alignment) are not exact, the tracking will not be correct and the GOTO will be inaccurate. The field of view of a 26 mm eyepiece on the Meade ETX-90 is about one degree. The straight viewfinder 8 x 21 mm has a field of view of 6.8° straight or 6.4° for the right-angle viewfinder. It is possible to have the star appear in the eyepiece 90% of time on GOTOs with a precisely completed setup. For a less precise setup, the star may not appear in the viewfinder. It might appear just outside the viewfinder's view.

What Affects the Meade ETX Autostar Observation System?
The perfect result of a process is the precise completion of all of the steps that lead to the result. The more precise each step is, the more precise the end result will be. Every little error introduced at each step of the process results in larger error at the end. A precision result can only be achieved if all of the steps are completed with precision. For example, entering the exact Altitude and Longitude of your house instead of choosing the closest city in the Autostar would introduce less error. The closest city could be many miles away. Entering the exact time read from an atomic clock instead of the time from the microwave oven would introduce less error. The time on the microwave oven might be inaccurate. A tripod that is not perfectly level would cause the Azimuth movement (horizontal turning) to not be fully horizontal. This inaccuracy could also cause the Altitude movement (vertical) to not be plumb. Your polar alignment and star alignment therefore would not be precise. The Meade Autostar also compensates for a degree of free-play on the motor and drive gear system. There are settings for the degree of telescope drive system free-play. These settings must be precise as well in order for polar alignment and star alignment to be accurate.

What Gives You Consistency?
There will be no consistency without precision steps. All of the stars are many light-years away. Therefore, a small error here, a little inaccuracy there, and things start to add up to create significant problems. If setup properly, the Meade ETX Autostar telescope is amazingly precise even at such a low cost.
There are no overall instructions for the beginner. There is a manual for the telescope on how to use the telescope. There is also the manual on how to setup the Autostar. There may be a manual for the tripod. These manuals are not integrated. They deal with each piece of equipment individually without any integration between them. It is important that each piece work with the other pieces.

The Goal
My experience is that, with a proper and precise setup and alignment (polar alignment and star alignment), you can expect better that 80% of your GOTO targets will appear (not necessarily centered) in the 26mm eyepiece of the Meade ETX-90EC. All target stars will appear in the viewfinder. A somewhat less precision alignment, will have all the target stars appear in the viewfinder but not necessarily in the eyepiece. If you follow the instructions here, you will get good GOTO accuracy and night-after-night consistency