Clear nights, and the NOSS 3-4 rocket brightness behaviour

A series of clear nights the past week, allowing a series of observations of the STSS-ATRR rocket (09-023B) and two Keyholes, USA 186 (05-042A) and USA 161 (01-044A). 09-023B keeps being an interesting target, as its orbital evolution is that quick that it necessitates continuous coverage. The current orbit projects decay around mid-August.

About a week ago, on May 19-20th (see here), I obtained images on the NOSS 3-4 r (07-027B). This spent Centaur rocket of the NOSS 3-4 launch shows a slow brightness cycle. I obtained some partial brightness profiles from the trail photographs, including an interesting one covering one of the brightness peaks:

(click diagram to enlarge)

It can be clearly sees that this (10.05 s) part of the cycle consists of two components, a slow modestly exponential brightness development with a short narrow peak superimposed on it.