Astronomy
Astronomy has a long, storied history among the Stenza, and even before they were a unified force, and certainly before they braved the void of space themselves, they were world-class astronomers. Astronomy as a science is deeply connected to religion, and is still called, in the native language, "the study of the divine" (râvgehi). In fact, the astronomer is considered to take a complimentary approach to studying the universe to the religious expert; where the latter considers the nature of the gods as divine beings, the former examines what the gods have created (i.e. the stars and planets, among other things) and what that can tell people about the universe.
The science of astronomy underwent a dramatic shift when interstellar travel became possible. Now an astronomer could check all of their estimates about how far away certain stars were by actually going there. This has led to a lot of refinement, as well as a resurgence in the use of parallax research that came with access to extrasolar planets on which to land and view an entirely different sky. (And, as a confirmation, now it was possible for teams to check that they have the right star by sending independent probes, manned or otherwise, to the location and seeing if they encounter one another.)
Utility
Astronomy has a lot of practical use in designing subspace drives and ship engines (which run on space dust), navigating the interstellar and intergalactic void, and mapping the galaxy, among a host of other projects. It is also useful theoretically when it comes to seeking to understand the universe. Measurements gathered through expeditions cross-checking the distances between stars have contributed greatly to understanding the dimensions of the galaxy, and similar expeditions (often on the same ships) have been able to collect data on space dust, subspace, nebulae, star formation, the various iterations of star deaths (novae, neutron stars, black holes, etc.), and a host of other space pheonomena in various parts of the universe, and often up close and personal. This has been widely considered a boon of scientific knowledge.
I love the little tidbits about the history of astronomy and how it has changed with interstellar travel.
I imagine if we could fly to stars with no trouble it would be a lot easier to confirm all of our measurements. And think of the things we could discover!