H Eric,
Without seeing the images, it's tough to know what the problem is. There are two things I can think of that might be the issue.
1) The stars are too faint relative to the background for AIJ to find a unique centroid.
2) If calibration was done incorrectly resulting in negative values of mean sky background, centroid may fail.
If neither of the above seems to be the issue, send me one of your fits files to (karenacollins atat outlook dotdot com) and a screen grab showing the apertures you have placed that produce the errors and I'll take a look.
Karen
On 11/10/2018 5:29 PM, Eric [via AstroImageJ] wrote:
Hi,
trying to do ensemble differential photometry. I've managed to get through a few previous image runs.
After using DP to plate solve and having these images sent to a separate folder I then open up these solved images via image sequence.
When I attempt to place the photometry apertures I'm getting the following error message,
***ERROR: No signal for centroid in aperture C1 of image 1st test image 90sec.fit.
********: Measurements are referenced to the non-centroided aperture location
***ERROR: No signal for centroid in aperture C2 of image 1st test image 90sec.fit.
********: Measurements are referenced to the non-centroided aperture location
***ERROR: No signal for centroid in aperture C3 of image 1st test image 90sec.fit.
********: Measurements are referenced to the non-centroided aperture location
***ERROR: No signal for centroid in aperture C4 of image 1st test image 90sec.fit.
********: Measurements are referenced to the non-centroided aperture location
***ERROR: No signal for centroid in aperture C5 of image 1st test image 90sec.fit.
********: Measurements are referenced to the non-centroided aperture location
***ERROR: No signal for centroid in aperture T6 of image 1st test image 90sec.fit.
********: Measurements are referenced to the non-centroided aperture location
***ERROR: No signal for centroid in aperture T7 of image 1st test image 90s
Any help would be appreciated.
Eric
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