Photometry
The photometry tool can be accessed through the menu "Analyse" or through the icon (red and blue circle with "123" on top of it).
As you choose this action, a new window pops up, where photometry results will be displayed. If you click somewhere in your image, a circle appears, centered where you clicked, and a line is written with photometry results :
You may have to extend the Photometry window to see all pieces of information.
The name of the image is written, as well as the position of the points you just clicked.
If you proceed as above, different parameters are set by default by the software :
- "Star's radius" : The size, in pixels, of the displayed circle around the point of interest (usually a "star"), over which intensity of pixels is integrated to get the "Star's Intensity".
- "Sky's radius" : The size of the, not displayed, circle around the point of interest, over which intensity of pixels is integrated to get the "Sky's intensity".
Those parameters can be set in the "Photometry setting" menu. Besides, you may also fix the position (X and Y, given in pixels) of the "star" - or any other point of interest. This allows a very fast procedure, to measure photometry in many different image.
More information about the choice, and meaning, of the parameters are given in the manual description of the "setting".
Once you have done all photometric measurements you need (on different images, or on different points), you may edit them through the Edit Menu in the Photometry window : you are allowed to cut, copy, select ...
The easiest way to work out those numbers is to save the File as ... an excel file. You may then work out your data as you wish with your favorite spreadsheet or other dedicated software.
a very important point : To be more accurate, you may select the "magnifying glass", and zoom or un-zoom in your image. You need then to select again "Photometry" to make the photometric measure. If you want to stop doing photometry, you have to select the menu "Analyse/Measure". If you simply select one of the selection tool, it won't work.
All the procedures about photometry (including setting the parameters) are described in a podcast :
.....
Do not forget that SalsaJ does a single thing at a time. If you are doing photometry, you cannot do another thing at the time. You need to close all the windows.
--
