In an attempt to find a way for the IPP to identify which exposures show moon glints, I examined a series of Three Pi exposures that had small moon angles and had visible glint features. All exposures are in the i filter.

exp_name	exp_id	dateobs	moon_angle	moon_phase
o5080g0156o	94818	2009-09-06 10:02:30	19.9828	0.547319

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exp_name	exp_id	dateobs	moon_angle	moon_phase
o5080g0160o	94822	2009-09-06 10:08:51	24.5752	0.547387

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exp_name	exp_id	dateobs	moon_angle	moon_phase
o5080g0164o	94826	2009-09-06 10:15:03	32.6811	0.547452

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exp_name	exp_id	dateobs	moon_angle	moon_phase
o5080g0166o	94828	2009-09-06 10:18:16	19.8979	0.547486

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exp_name	exp_id	dateobs	moon_angle	moon_phase
o5080g0171o	94833	2009-09-06 10:26:19	36.004	0.547569

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exp_name	exp_id	dateobs	moon_angle	moon_phase
o5080g0173o	94835	2009-09-06 10:29:37	31.0689	0.547603

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Sky brightness levels for matched pairs of ISP and GPC1 images as a function of airmass and moon angle. The ISP data is consistent with airmass effects. The GPC1 data shows strong glints at moon angles ~ 30-35 degrees.

The same data, now plotted as differences in sky brightness. The pairing mitigates the airmass trends, showing that GPC1 gradually becomes brighter relative to the ISP, with the glints influencing the ~ 30-35 degree range. All "GPC1 bright" pairs with moon angle > 50 degrees all come from the same night, and the observing logs note clouds. Therefore, these points are likely not to be related to the telescope, but to variations in cloud cover.