Hi Tamar,
On 2/16/2019 5:22 AM, Tamar [via AstroImageJ] wrote:
Hi,
I am trying to perform multi-aperture photometry on an open cluster image, and I am encountering several difficulties that I would appreciate your assistance with:
1. I check the "Total comp star counts" in the "more aperture photometry settings" to have the total counts displayed in the measurement table. However, this data does not appear when I generate the table.
Just to make sure, you must be running Multi-Aperture to see total comp star counts, and you must have at least one comparison star selected. In that case, you should see a data column labeled "tot_C_cnts"? It may be all the way to the far right of the table.
you should be able to locate it in a pull down menu by opening the pull down and typing 't' until you see it. Does that solve the problem?
2. Apertures that were previously chosen in a certain image cannot be deleted from it, even when I delete the relevant lines from the header, or use a different fits file. They keep on appearing when I press the "perform multi-aperture photometry" icon. How
do I make AIJ completely forget about these apertures?
In the Mutlti-Aperture setup panel, deselect "Use previous N apertures..." before clicking "Place Apertures".
3. I obtained an astrometric solution for my image using Astrometry.net and I am using the solved image to perform aperture photometry. When I open the image in AIJ it shows the right coordinates. However, when I export the results of the multiaperture photometry,
including also the RA-DEC coordinates, it prints out coordinates which are a bit off for the comparison stars (and the right coordinates for target stars). What is the cause for this?
I don't have enough information to venture a good guess, but some ideas are: proper motion differences if the difference is small, or an inaccurate plate solution.
I would appreciate your help!
Tamar Faran
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