I investigated diff_id 65024, skycell 1383.111 to find out some of the causes of the false Mops Detections. 

The following is a rough count of the different classifications of detections:

||type || number ||
||burntool || 49 ||
|| cosmic ray || 20 || 
|| star wing || 88 || 
|| star core || 37 ||
|| round || 40 ||

"round" refers to objects which appear generally psf-like in the diff image (round and subtending more than a pixel or 2).  Most, when investigated further, are small cosmic rays which are convolved into something extended, but probably a bit smaller than the convolved PSF.  (Edit EAM to further clarify 'round')

Here are some examples from each of the categories.

= Burntool =
There are 4 detections on this burn.

[[Image(mopsburntoolf.png)]]

= Cosmic ray hit =
There are 2 cosmic rays here, each resulting in a detection.

[[Image(mopscrf.png)]]

= Star wings =
2 bright stars, the wings are detected (also, a burntool in the far right)

[[Image(mopsstarwingsf.png)]]

= Star cores =
These are subtractions that are not quite lined up.

[[Image(mopsstarcoref.png)]]

= "OK" =
Sometimes these are real, most of the time these are actually not real (if you look at the warps).

[[Image(mopsokf.png)]]