Mass Effect 2164
A MEJ needs a course record, or “Star Chart” to guide the pilot. Ideally, this is an up-to-date and recent record of the celestial objects and intra galactic currents & energetic weather between the origin and destination of their course, one reported by a recent traveler. The older and staler the readings of the chart, the more dangerous the jump. Most charts for commonly-traveled routes are available for purchase. Significant trade corridors usually have ones only a few days old available to any pilot making the jump. Star charting heretofore-unknown paths between stars are often kept jealously secret by their owners, and may require an adventure or a favor to obtain.
Attempting to jump to a star without any chart at all is insanely dangerous, the work of near-suicidal crew of adventurers willing to risk everything in order to obtain a secret route to some hopefully unplundered world. Only a masterful interstellar navigator has any real hope of surviving such a blind jump.