There’s never any telling which show from the Grateful Dead’s history you’re likely to hear when you go see the Dark Star Orchestra—it could be the Matrix from 1968; it could be Winterland from 1974; it could be RFK Stadium from 1991. As a fun way to tease hardcore fans who own every Dick’s Picks and have garages full of Memorex cassettes, they won’t tell you which show they’ve just performed until after it’s all over. But mimicry is not the DSO’s stock in trade; the band aims more to capture the feel of the Grateful Dead instead of the exact note-for-note replication of certain historic shows. Expect an especially vibrant four-hour performance this weekend, when, if the planets are aligned, we may go, you and I, while we can through the transitive nightfall of diamonds on Friday, April 17, at the Wells Fargo Center, 50 Mark West Springs Rd., Santa Rosa. 8pm. $20-$35. 707.546.3600.