Changes between Version 6 and Version 7 of Durham_MDS_Testing

Timestamp:

Jul 14, 2009, 11:55:01 PM (17 years ago)

Author:

shaun.cole@…

Comment:

--

Durham_MDS_Testing

@@ -6 +6 @@
 == General image quality == 
 
-There are some significant flat-fielding issues, especially near the edges of the field. Zooming in, there are some strange re-sampling effects in the stack - these are going to seriously mess up faint-source science: 
+There are some significant flat-fielding issues, especially near the edges of the field. Zooming in, there are some strange re-sampling effects in the stack - these are going to seriously mess up faint-source science, for example: 
 
-[[Image(example1.jpg)]] [[Image(example2.jpg)]]
-
+[[Image(example1.jpg)]] 
 
 I’m quite worried about the ‘chunky’ effect seen in (e.g.) the abrupt level changes, and the mottling effect. I’m guessing that all of these are a combination of convolution, dealing with NaN-ed regions in the input frames, and how the sky is dealt with. I’m trying to use the deep CFHTLS Groth Strip and EN1 (INT) images to figure out how much of that mottling is noise, and how much is contributed by faint galaxies - I hope to come up with something quantitative. We should be worried about that that.
@@ -15 +14 @@
 
 More worrying: here is an example of a comparison of g and r-band stacks of skycell 030. Something seems to have gone quite badly wrong - especially with g. I suspect this is a masking issue - looks like something from a bright star has infected the image?
+