On the night of September 5-6 I captured a series of images again (between 23:11:22.30 - 23:16:32.35 UTC, Sep 5, 2010) allowing the construction of a curve. Below is the diagram: I find it best fits a periodicity of 60 seconds:
Earlier period determinations were:
20 Jul 2010: 61 seconds (see here)
2-9 Mar 2010: 88 seconds (unpublished)
19 Nov 2009: 62 seconds (see here)
25-27 Aug 2009: 71 seconds (see here)
I should actually revisit the two determinations (Aug 2009, Mar 2010) that are well off from 60 seconds to see whether I didn't make mistakes there.
As can be seen, I again captured a solitary anomalous glint produced in the "valley"part of he curve. Something very similar happened earlier on July 20th. Both glints happened near a brightness minimum. Below is imagery of the latest glint from September 5 (showing one image before the glint, then the glint image, and an image after the glint), and a comparison diagram of the July 20th and September 5th glints:
These spikes are quite specular in character, and suggest there is a flat mirroring surface attached to the object on (if the slow brightness variation of the object is due to exposure of long versus narrow sides) one of the narrow sides.