Best slide film for loooooooooong exposures?

I mainly shoot with a DSLR now, but I'm going to be using the old film body for some nice long star shots (>45 minutes). I've used Velvia 50 and 100F, Provia 100F, E100VS, E100SW, Sensia, etc--but never much for really long exposures. Also, I've heard that some of these have color shifts after a certain amount of time.

Does anyone have any recommendations?
Thanks.

Always had good luck with Provia 100F and 400F but my looooooooooooong exposures are rarely more than an hour. They really don't have much in the way of color shift - unlike Velvia 50 which turns everything green. Can't comment about the others - have used them but not like this.

Yeah, I was leaning toward Provia anyway. Glad to hear that you've tried something similar and didn't experience any color shift. Have you got any of those photos online?

Mmm... no but I'll see if I can dig one up.

I like the blacks of Kodachrome 64