On 26th august, 2019 and after a month of waiting at a road-side stop commuting to work using the public bus system in my home town of peterborough, cambridgeshire, (uk) every week; i have noticed an unusual aerial phenomenon in the sky. at approximately nine forty-five pm mostly on a monday or wednesday and less often on a thursday, twice a month; a pulsing crimson ball of light is seen at approximately fifteen thousand feet; flying east-south-east parallel to thorpe road (a1179) over and past the cathedral towards whittlesey. the speed is thought to be twenty to thirty miles per hour. the sighting is made from a position standing facing south at the junction between alderman's drive and thorpe road. if one was to hold a ten pence piece at an arms-length up to the aerial object, it would cover it. i would guess the distance from the object at the junction would be approximately 450 meters. the pulsing light is unlike any other known aerial light configuration (helicopter, drone or plane) with a pulse occurring every two seconds and makes no sound. no photos have been taken at the time of this record, however the witness is confident that with this newly discovered regularity of occurrence; photos would be achievable with any good quality flash or night vision camera. the witness is curious to find out if the unusual aerial phenomenon has been seen by other local people and if there is an historical record of similar occurrences. the appearance of a white flashing light in the distance, but at a similar height occurs a few minutes prior to the aerial phenomenon and the witness is confident that the light configuration is consistent with that of a conventional helicopter.