This constitutes the central part of the tutorial, where we perform the actual photometric reduction of our FS CMi science images. 


Preparing the Photometry dialog box


Navigate to the Photometry menu and select Photometry to display the corresponding dialog box:



A detailed explanation of the contents of the Photometry dialog box is provided here. It is highly recommended to read that section for a comprehensive understanding.


  1. In the Input set section, click the button with the 3 dots to designate the folder containing the FS CMi science images. As per step 2 in this tutorial, this folder is located within the Documents directory of your PC, in the Phoranso -> Tutorials -> FS CMi 20230329 -> Sciences subfolder. 

  2. As explained in step 4 of this tutorial, we will calibrate our FS CMi science images during the photometric reduction. To achieve this, ensure that the Skip image calibration option in the Options section is unchecked. Subsequently, enter the name of the Calibration group (created in step 4), in the Calibration group field using the button with the three dots.

  3. Use the default subfolder names in the Output results section. Phoranso will store the calibrated images of FS CMi in a subfolder Calibrated. Additionally, the images from the Calibration group used during the calibration process will be stored in the Masterfiles subfolder. Finally, the reports generated at the end of the photometric reduction will find a home in the Reports subfolder.


With these configurations, your Photometry dialog box should mirror the one depicted above.



Using the Photometry Settings and Report Settings


Before initiating the photometry process, it is important to note that further options influencing the photometry can be accessed from the Photometry Settings dialog box. To reveal this box, navigate to the Photometry menu and select Photometry Settings.



We recommend employing the above configuration. Each setting is explained in detail in this section. This configuration entails the selection of a ringset with a star aperture radius of 4 pixels, a gap radius of 6 pixels (measured from the star aperture radius) and a sky annulus radius of 8 pixels (measured from the gap radius). While experimenting with multiple ringsets is a possibility, such exploration goes beyond the scope of this tutorial.


Now, let's delve into the Report Settings. Navigate to the Photometry menu and select Report Settings to display the corresponding dialog box. We propose the below configuration, indicating that we want to produce an AAVSO, CBA, Excel and CSV report with the photometric data of FS CMi. Detailed explanations for each setting can be found in this section.




Starting the Photometric reduction of our FS CMi images


With all configurations set, we are now ready to launch the photometry process using the Photometry dialog box. At the bottom of the box, you will find five buttons, which are explained in this section. 


  1. Click the left most button  Start/Resume Photometry to launch the photometric reduction. As explained earlier, this will first calibrate the FS CMi science images followed by the photometry process, starting from the calibrated images.


  1. To track the progress of the reduction, click the Show Log File button, unveiling a Logging window. Its contents will resemble the example provided below.



  2. Depending on the CPU speed of your PC, the calibration and photometric reduction of the 104 science images will take approximately between 5 to 15 minutes.


  1. In the next step of the tutorial, we will learn how to display light curves of the variables processed in our FS CMi images while the photometry is in progress.



Proceed to step 6 of the tutorial.