At approximately 1812 on 15 november 2017, i stepped onto my back patio (facing north)to start my grill. i immediately noticed a cluster of what appeared like strobe lights pulsing so rapidly that i could not count the number of pulses. as a retired airline pilot, my first thought was it was a new type of aircraft. the lights were far brighter than aircraft strobes and there were far more (i estimate 10-12)than even on 3-4 aircraft. these lights were at approximately 280 degrees magnetic and at an elevation of 30 degrees (verified by using phone apps afterwards). what really caught my attention was this was almost identical to what i saw previously (2015, i think) while the strobing lights were blue white when first seen, as i continued to watch, the group of lights "appeared" to either come closer or "zoom in". when this happened,the strobing lights took on individual hues of a reddish orange, blue white, and a violet/purple. i went inside to grab a camera, came right back out, all of the lights were gone, with no trace. the group of lights never changed position while i was observing, other than the "zooming effect".