Harlock and his crew are practically banned from Earth while they fight to protect it from an alien race called the Mazone, which resemble beautiful women in appearance. In Ideon the group who discover the "Solo Ship" and the Ideon end up being pushed away from their homeworld as well, with nowhere to run while being chased by the mysterious Buff Clan that resemble humans themselves. In both shows, the casts home is ... their spaceship, with nowhere else to go.
If you can appreciate old art and animation it's easy to say both shows still look great to this day, with the exception of Ideon's recurring stock footage here and there. The Harlock series has better pacing and a much more likeable and developed cast all around, while Ideon is strikingly a bit more darker in tone and very desperate in nature. Both have incredibly impressive soundtracks, orchestrated and all. By the end of these two shows you yourself might be out of breath, as you'll feel like you went through these huge adventures personally. Typical of Tomino stuff Ideon is a little quirkier at times and has mecha, but overall the show is far more space drama than some of his other works. Overall, both have a lot of similar themes and ideas, with very different styles and executions in terms of writing/directing. But in the end these are two amazing, action packed, and adventure filled classic space dramas.
And please note: Be Invoked IS the ending to Ideon. Episode 39 is just a sampler.