Despite being some 222 miles
away, it's possible from San Francisco to observe rockets launching from Vandenberg.
Here are some quick tips I use for trying to catch a launch:
Find the website that lists the countdown, and keep an eye on it. For
SpaceX launches, you can find a it here. SpaceX will broadcast a
"live" feed on X starting 5 or 10 minute before launch. (I put "live" in
quotes because it's annoyingly time delayed, which will be important
later.) You don't need to look at the screen, so I leave my phone in my
pocket and listen on headphones.
Use a compass app on your phone and find a bearing of 154 degrees.
Look in the general vicinity of the compass bearing before the
countdown reaches zero, because of that annoying time delay. Scan around
with your eyes a bit. Once you spot it, it'll be obvious! It'll be moving
up remarkably quickly, given how far away it is. If it's near sunset, you
can see the exhaust plume illuminated by the sun. If it's in the middle of
the night, the plume will be illuminated by its engines. Both can be
quite visible, but will look very different.
You might intermittently lose sight of the rocket if clouds get in the
way. But, you'll also lose visual contact when MECO (Main Engine Cut Off)
occurs. Because of the "live" feed time delay, it will disappear from
view before you hear the MECO call on the audio feed. Several times I've
been observing a launch, become frustrated that I lost it, then only
seconds later heard the MECO call 😂
Keep watching! For SpaceX launches, You might be able to see the
boostback burn, that returns the first stage to the landing area.
Maaaaaaaaaybe you'll be able to see the second stage light. Maybe.
Launches are completely observable with the naked eye, but binoculars
can help and provide more detail, if you have them! A tripod can also be
useful. For SpaceX launches, with binoculars you can sometimes see nine
points of light from the first stage's nine Merlin engines!