Okay, I'm going to get my greatest pet peeve concerning The Herculoids out of the way:
The Herculoids' home planet is named "Amzot". Not "Quasar".
Yes, I know: you'll find Quasar given as the name of the planet in a lot of online references to the series. (Don Markstein's Toonopedia refers in the "Herculoids" entry to "the land of Amzot on the planet Quasar"(!) Where'd he come up with that?) And, yes: Quasar is the name of the planet in the 1980's Space Stars version. But to this long-time fan, the name of the planet is, and always will be, AMZOT! For two reasons:
1) I have never liked the convention, common in children's books/cartoons/TV/etc., of using an astronomical term as a name for another (usually unrelated) astronomical entity. A quasar is a specific term: also known as a "quasi-stellar radio source". Naming a planet "Quasar" is like naming its moon "Galaxy". Imagine dialogue from some space-adventure show that went "There used to be three planets - Moon, Nebula, and Satellite - orbiting the star Asteroid, what happened to them?"
2) "Amzot", as a word, is just plain cool. If it hadn't already been taken, I'd have loved to come up with it as the name of a character or location in one of my stories. (I've been able to come up with exactly one cool name in my writings: Velshen'narith, the main character of my High Priestess format, so far unutilized.)
It comes down to a question of what constitutes "canon" (i.e., the "official version" of the Herculoids story). Fans of Sir Arthur Conan Doyle's Sherlock Holmes consider only the sixty stories written by Doyle himself (56 short stories and 4 novels) to be "canon", and everything else (including Nicholas Meyer's novels The Six-Percent Solution and The West End Horror, however entertaining, to be merely "fictional".) As for the Herculoids, the original 1967-68 series is certainly canonical, or else nothing is. But what of the 1981 Space Stars incarnation? I'm inclined to say "no", because aside from most of the vocal talent (Mike Road, Don Messick and Virginia Gregg reprising their roles from the 1967 run), very few (if any) of the original writers or artists were involved in both series (at least as far as I've been able to find).
Actually, it's a little surprising how few times the name of the planet is even mentioned during the original series. The seemingly-endless parade of serial invaders and despoilers that plagued Amzot were just as likely as not to refer to it as "Zandor's planet", and even Zandor and the others themselves were just as wont to call it "our planet". The planet is not named in the narrated version of the opening credits; it's referred to simply as "Somewhere out in space".
The name "Amzot" does appear early in the first season; however, it isn't on the show itself that it is first used, but on another famous Hanna-Barbera series, Space Ghost and Dino Boy. Space Ghost had debuted the year before (1966), and his success led H-B to create a whole slew of other action-adventure cartoons for Saturday morning TV (including Birdman and the Galaxy Trio, Mighty Mightor and The Herculoids themselves. For the second season of Space Ghost, H-B produced six new episodes comprising a single serialized story known as "The Council of Doom". Six of Space Ghost's more familiar villains - Brak, Zorak, Moltar, the Creature King, Metallus, and Spider Woman - united to form said Council with the intent of pooling their talents and resources to destroy Space Ghost once and for all. "Council of Doom" was as much intended to serve as an introduction to the new Hanna-Barbera heroes (the ones who appeared on CBS, anyway) as anything else* - four of the installments had Space Ghost and/or Jan and Jace meeting Mightor, Moby Dick**, the cast of Shazzan … and the Herculoids!
In part four, "The Molten Monsters of Moltar", Space Ghost is captured by Moltar and forced to board a spaceship for a "one-way" trip to the planet Amzot. Landing on Amzot, Space Ghost (still in the clutches of Moltar's "molten monsters") encounter Zandor and The Herculoids, who destroy SG's captors and enable him to return to Moltar's planet (not named) just in time to rescue Jan and Jace from certain death!
The first mention of Amzot within the Herculoids' series itself comes in episode #19, "The Time Creatures".
*… since these six episodes were all that were produced for the second season of SG (the rest of the "season" consisting of yet more reruns of the first season episodes).
** I kept wondering what that distracting rattling sound I kept hearing during Moby Dick episodes was; now I know it's the sound of Herman Melville rolling in his grave at the fact that his great literary work had been trivialized by a cartoon factory into a kids' show.