Ah, Wikipedia. Currently browsing history features all sorts of articles on planets, stars, white dwarfs, multi-star solar systems, accretion discs, the Roche limit, stellar collisions, virtual black holes and stars literally tearing their planets apart....
Anyway.
Sorry, you hadn't clarified you were talking about it as a planet around another star - I was the only one who'd talked about it as being the observed "dragon star", and (at least in my mind) only if it was within the solar system. A more distant origin would mean they have to be observing the star itself.
I was also going to say that even a glowing planet wouldn't be visible against the glare of its star, but that started my Wiki adventure because I remembered about
Sirius being a double-star with a white dwarf, which glows. (Main star is 1.7 x the Sun's radius; dwarf star is Earth-sized.) That
is visible in a telescope, and was discovered in the mid-1800s - so still somewhat ahead of Ishgard's technology level.
Also the first scientific detection of an
exoplanet (ie. orbiting a star other than the Sun) didn't happen until 1988, although was theorised a lot earlier.