This has likely been discussed many times, but can someone point me in the right direction for expanded explanations on using the Dark Heresy powers with the Rogue Trader (and now Deathwatch) psychic power rules? I'm debating on which one to use. The Ascension book kind of merges them but not exactly, which looks pretty good.

Unfortunately all we have so far is a little sidebar on this topic. Converting DH to the RT system is more or less "roll WP and try to avoid doubles" which is IMO rather DERP. Converting RT to the DH system involves rolling your Psy Rating (or fewer) D10s and trying to beat the power's threshold (converted as best you can based on existing DH powers) and shifting the threshold up or down in increments of about 4 for difficulty changes. From what the designer diaries are saying we should be getting a new psyker rules set in Daemonhunters that is supposed to be designed to "bridge" the DH and RT/DW systems (made suddenly more important by squads of FULL TIME Inquisition Astartes psykers! [Grey Knights]). My best advice is to wait and see what they did in Daemonhunters if you can, or do your best with the DIY conversion if you need it sooner.

I am much more a fan of the DH system for psykers, since it does a much better job of showing the difference in difficultiy between using a minor parlour trick and a supremely dangerous and powerful technique (You need to beat a 7 versus needing a 24, for example) than both powers being essentially a WP test ("so using telekinesis to lift a set of keys is just as hard as burning a daemon's soul by setting my own soul on fire with psychic rage and hoping it dies first?")

A forum user attempted this project a while back. His work was quite impressive and is hosted on a different, non-FFG affiliated forum. I will post the link when I get home from work in a couple of hours.

Here is the link http://www.myth-weavers.com/showthread.php?t=91371

Thanks, I'll check that out. Hopefully in the upcoming Daemon Hunters book they'll have something as well.