Over the years there have been some rocket launches from Vandenberg Space Force Base (SFB) that have been spectacular even when viewed from here in northern Arizona. This requires that the launch occur during twilight. During the day the bright sky overwhelms the faint light of the launch; at night there is no light other than the glow from the rocket engines.
At twilight the sky is dark but as the rocket rises higher it is lit by the Sun and the exhaust gases from the rocket engines are illuminated. Twilight launches do not occur often so being able to see one is an infrequent event. Also, clouds can obscure the view reducing the number of times that one can see these events.
Last night–after a one-day reschedule owing to an abort at T-5 seconds–SpaceX launched a Falcon 9 rocket into the sky from Vandenberg SFB at 2109 MST. The end of astronomical twilight was at 2120 MST in Flagstaff (and 2154 at Vandenberg) so there was reason to expect a good show as the rocket rose out of darkness and into the twilight-illuminated sky.
It was a good show. It took a few minutes for the rocket to rise above the western horizon and into the light but once that occurred it was easy to see. The rocket was visible until 2115 and then was blocked by distant clouds. After it was gone, the glowing exhaust gases remained visible for a few more minutes then faded quickly.
Beautiful!
An explanation for the red glow can be found at SpaceWeather.com.
Edit: Added more photos and a link to SpaceWeather.com