Green flash on the western horizon, then a pulsing array of many small green dots in the sky

We were sitting and viewing due west from Marathon, TX towards Alpine, TX just after sunset in anticipation of the meteor shower. Shortly after sunset as darkness was about 90% closed in we both noticed a bright green flash over the mountains. Something like lightning, but there was no weather in the area at all—skies were completely clear. A second or two later we saw a giant array of green sparks in a circular type pattern (as if a giant fireworks display—but there was no fireworks display in the area because there is a permanent burn ban out here right now). This mass array of green sparks appeared to pulsate on and off for a period of 2-3 seconds after the flash. If I put my thumb in front of me with my arm extended, I’d say the array of green sparks in the sky would be about 3-times the size of my thumb. We both looked at each other and said, “What was that?” Neither of us had ever seen anything like that before, and we spend lots of nights under starry desert skies observing satellites and stars. Our exact location was: 30°12′34″ N 103°15′13″ W at 4060ft. Elevation facing west towards Alpine, TX, from Marathon, TX. I truly believe it was my first UFO/UAP sighting. I’m 54 years old and always been curious about them. Thanks for all the great work you do.