Bright Objects
There is no fundamental difference between the Find Bright and Find
Faint Objects modules; indeed the same
object finder is used by both. The
only difference is that Find Bright Objects:
- Works on an un-smoothed image, with the single global sky value
determined by correct frames.
- Uses a brighter threshold, namely
fbo_thresholds*(sky sigma)
where sky sigma is again determined by
correct frames.
- Runs before we've made a
local determination
of the sky level. This means that we haven't subtracted (much) power from
the wings of extended objects.
- Runs before the wings of bright stars have been subtracted
Once the bright objects have been found, the list of peaks in each object
is culled,
removing all peaks that are less significant than 3 sigma
(sigma, the pixel standard deviation, is determined locally).
Here are a few notes for when I write this section:
- Only saturated objects are currently subtracted
- Objects with centres off the frame are not handled
- We should discuss how to find centre/psfCounts for saturated objects
- Ghost removal belongs here