Removing Saturated Stars
sbursic wrote on Jul 07, 2009
Hello,
I am working on producing catalogs, but I first need to remove cosmic ray hits and over saturated stars from the images. I found one task in crutil that is supposed to remove cosmic ray hits (cosmicrays), but it doesn't seem to work. (Output image same as input)
I haven't found anything on how to remove saturated stars.
I've read you can create image masks manually to remove the saturated stars. Do you have any clues how to do that in IRAF? Or possibly any other tasks that I could use to remove the saturated stars?
I realize these are pretty open questions, so I greatly appreciate any help you can provide!
Thank you,
Shelly
I am working on producing catalogs, but I first need to remove cosmic ray hits and over saturated stars from the images. I found one task in crutil that is supposed to remove cosmic ray hits (cosmicrays), but it doesn't seem to work. (Output image same as input)
I haven't found anything on how to remove saturated stars.
I've read you can create image masks manually to remove the saturated stars. Do you have any clues how to do that in IRAF? Or possibly any other tasks that I could use to remove the saturated stars?
I realize these are pretty open questions, so I greatly appreciate any help you can provide!
Thank you,
Shelly
Erin Ryan wrote on Jul 07, 2009
Saturated such that the count levels are high or saturated such that your pixel values go to NANs?
In objmasks (in nproto) you set hsigma and lsigma which flags objects to be masked based on how bright or dark regions are when compared to the background. To mask only the saturated stars, you'd want to do a quick measurement to see how bright they are compared to the background and use that for hsigma. It should then pick up everything that bright or bright and put them in the mask.
In objmasks (in nproto) you set hsigma and lsigma which flags objects to be masked based on how bright or dark regions are when compared to the background. To mask only the saturated stars, you'd want to do a quick measurement to see how bright they are compared to the background and use that for hsigma. It should then pick up everything that bright or bright and put them in the mask.
sbursic wrote on Jul 07, 2009
Thank you for your suggestion.
To answer your question, the stars, in the image, have spikes in them and bleed out across the image causing false detections to occur while making the catalogs.
I'll try your method and see how things go.
Thank you!
Shelly
To answer your question, the stars, in the image, have spikes in them and bleed out across the image causing false detections to occur while making the catalogs.
I'll try your method and see how things go.
Thank you!
Shelly
sbursic wrote on Jul 07, 2009
Sorry, how would I do the measurement?
Thanks,
Shelly
Thanks,
Shelly
Last post on Jul 07, 2009