If you’re hoping to photograph Horsetail Fall this February, here’s a post from last year that outlines some of the basics about the timing and best locations. You’ll also find an article on my web site with a detailed description of the factors that go into determining the best dates to photograph this phenomenon.
Since every astronomy program seems to disagree with every other one, it’s hard to figure out exactly what the best dates are each year, but it appears that the window of best light will be a little later this February, from about the 12th to 22nd. Good luck!