and combined with slow-decay phosphors made for some beautiful "trail" effects
Thank you. This is such an under-appreciated aspect of vector games' unique look on real hardware. A pixelated display of any sort can only yield a rough approximation at best.
Why do you feel this way? With sufficient DPI, to me this is fairly easy to achieve. A few examples of emulation that look like they're doing a very good job:I think they have the bloom dialed up way too high, and maybe the trails aren't prominent enough, but I assume those are easy things to tweak.
https://www.youtube.com/watch?v=Z4lHsVueSj0
The bloom might be all right if they could replicate the intensity. Maybe with an OLED and sufficient HDR color depth, but I'm not seeing that here. It doesn't look like they did much CRT effect processing on the second two. The fireballs in Star Wars should glow the way the bullets in Asteroids do (albeit with quicker phosphor decay so not much in the way of trails).
Last time I played a well-maintained Asteroids cabinet, bullets had obvious bloom, but I was surprised to not see a trail. There wasn't any noticeable bloom or trails on the other objects. I believe the arcade monitors have fast decay phosphor like in regular TV sets, so any trail would come from persistence of vision, probably due to the brightness of the bullet.
I'm not sure about the Vectrex CRT, it may have longer persistence phosphor.