For context:
Telene is the world from the Dungeons & Dragons Campaign Setting known as Kingdoms of Kalamar, published by Kenzer & Company. I have most of their 3.X compatible materials, but I have been unable to find if, and where, Telene resides within the "Phlogiston" of the 'all encompassing' "Spelljammer" universe...
Does anyone even know if Telene is even within Sphere-Space?
While Kenzer has the right to use the D&D logo, they definitely did not have the right to Spelljammer, and may not have cared to in any event. WotC most definitely did not incorporate it (they were functionally done with Spelljammer by that point regardless) and Kenzer didn't bother trying to abstractly position it. That being said, outside of Spelljammer materials proper, and (to be quite frank) even considering them, one should always...
The Spelljammer fandom always has an answer, and the incarnate form of that answer, produced some eight years ago, is Nerik's fabulous sphere map. Nerik placed Tellenespace in grid square V6, lying just beyond the Arcane Outer Flow and not connected to any flow rivers, though there is a flow beacon there. Now of course, this isn't canonical (though Nerik's map takes into account as much canon information as it is able), but as a visual reference and source of inspiration at the very least, it should prove of use.
I'm not particularly familiar with Kalamar, but luckily some internet forumgoers are, in a 2013 thread titled Which Kalamar products reference space?:
Hey, the 3.0 KoK book has the main constellations and basic data on Tellene's moons and that's about it. No real info on "K-Space." The K&Co D-Team aren't real interested in SpellJammer, the only thing that K&Co ever published for a "SpellJammer" type game was HackJammer and that was completely done by Freelancers and had some serious HackMaster errors in it. There was some major errata for it.
The Kingdoms of Kalamar setting book does have some information on the planet's solar system, but according to this thread, it has nothing specific linking it to Spelljammer's system of crystal spheres.
However, Kingdoms of Kalamar was never a first-party D&D product, despite the 3e products using the D&D logo. The original 1990s Kalamar sourcebooks were not published by TSR, nor under license from TSR, and thus could not have canonically have appeared in the Spelljammer at this time.
In November 2000, a Wizards of the Coast press release states that Kingdoms of Kalamar would be an "official" D&D setting for D&D third edition. However, WotC had dropped support for Spelljammer at this point, and the Kalamar sourcebooks (according to the thread) appear to have included no Spelljammer material. The only Spelljammer content in 3e was in Dungeon magazine #92 (May 2002) and it was deliberately disconnected from the crystal sphere system of space.
The 2005 sourcebook HackJammer is, according to this site, a parody of Spelljammer, for the HackMaster 4th edition rules, and set in Garweeze Wurld, not Kalamar. Since the only Spelljammer-like content produced by Kalamar's publisher was not set in Kalamar, didn't run in D&D, and is described as a parody, I don't think it counts as a connection.
Wikipedia says the publisher made Kalamar the official HackMaster campaign setting in 2006, but that was after Kalamar products stopped bearing the D&D product logo.
In short, as far as I can tell, Telene has no official place in the Spelljammer world, at least not canonically, because none was ever defined. TSR didn't allow it in 90s Kalamar, WotC ditched Spelljammer during '00s Kalamar, later Kalamar isn't D&D, and HackJammer isn't Kalamar.
