Your astral body can indeed "travel" through the past, and so can your mental body. That doesn't mean you can affect the past or anything like that. You're just exploring memories and imprints left by the past. You're not really present in the past.
It's very helpful in learning history properly. However, you can also still see self-delusions and enemy manipulations. Just because you think you're traveling to the actual past, it doesn't mean it's actually happening.
For example, there are people who claim this or that about enemy programmes or NS because they "went to the past" or had a past life regression. From the content you can understand whether they're lunatics or actually saying partial or complete truths about it.
For example, I've seen new age people in the GLBT claim all sort of nonsense about sexuality in the past, and I've also seen biased people on the opposite side claiming homosexuals and bisexuals were scorned by society and there was laws against them. Who's correct? Neither, as private life in pre-xtard civilisations was private life and treated accordingly.
You can also "travel" to any possible future. How accurate is that will also vary. Even if you're actually going there, it doesn't mean you're seeing the most probable future. That requires oracular ability around Lady Maxine's level and beyond, which requires hard work to achieve.