Object pulses in the red-blue-purple spectrum.

About 9 PM CST I witnessed 2 objects low on the horizon about 1-5 miles north-west of Saint Charles East High school, located in St Charles, Illinois (60174).  My condo, observation  point, is about 0.5 miles south-east of STEHS.  Objects appear to be bright stars or airplanes, as I live in the flight path of Du Page airport. Initially, I watched the objects for about 4-5 minutes.  Because the objects did not move and were very bright, relative to the stars in the sky, I took immediate notice.  I walked away from my observation point, my walk-in closet window, to determine if it was possible to observe event from another location.  To convince "myself" that something was really happening, I tried to observe the strange objects from other windows, my 1st level front porch, and from my 2nd level rear porch balcony. I was only able to observe the objects for a short period of time (5min.) from one alternate vantage point, my rear condo balcony.  Next, I returned to my! initial observation location, walk-in closet window, to notice that the two bright stars have moved lower in the sky, and to the horizon. The objects maintained the same relative displacement to each other.  I watched the objects for about 10min.  To my naked eye, the objects are small.  Also, I am not viewing the objects with binoculars or similar optic devices.  Next, I remained cog nascent of this event for about 30 minutes.  
After about 45 minutes, while hanging a shirt in my closet, I noticed that the object on the left had disappeared, and the object on the right is now  pulsing brightly in the red-blue-purple spectrum.  The object was also changing in physical size and shape.  As the object pulsed with a frequency of about 2-3 seconds it remained stationary for another 15 minutes and continued to pulse in colored lights until it vanished.  As a final note, I never observed any directional movement of the objects, only a pulsing of the object, as it increased-decreased in vo! lume by an order of 10.