At dusk in 1966 or 67, three lights in formation or triangular craft with no visible substance floated silently into the West.

This took place at our ranch , 7 miles out of our tiny town of Arbuckle, CA.  in the Sacramento Valley  near the Foothills to the West.
Dad and I were outside on a warm summer evening after dusk.
It was 1966 or 1967.
We saw an enormous,low flying,silent,very slow moving triangle  of , I think,  three lights,  no real interior substance, more like dim lights ( the brightness of small stars) in triangular formation moving as one unit.....giving the feel of a "solid" object.   There was no movement of the lights, no blinking or rotation, just total "stillness" , even though they floated across the sky, slower than anything we had ever seen in the sky........ and an enormous  and silent  presence.
Stunned, we acknowledged to each other what we were seeing, Dad telling me to run to the Jeep and get the binoculars, QUICK!    I took off and fumbled wrecklessly, not wanting to miss any of this show.  I could not find the glasses and so ran back quickly.    All that was left in the sky was off into the distance, over the Western Foothills.  A  bright Turquoise streak, like a whisp of cloud, as if the speed of the thing was such that it left this turquoise vapor behind, in the early twilight.  All the reading I've done throughout the years of others' sightings, I've never heard of anyone else seeing this Turquoise light streak.  Anyone?  Please let me know.  I'd be greatful!
Witness indicates that the date of the sighting is approximate.  PD