When you create or edit an ID Card, you will see one or more icons next to the names of the Target, Reference, Check and Comparison stars in the Target - Reference - Check - Comparison stars section.


One of the icons is the Enable/Disable for Photometry checkbox. It lets you select which reference stars and comparison stars Phoranso should use for photometry from your set of selected stars. To enable a star, select it from the dropdown list and check the box. To disable a star, uncheck the box.


Practical ensemble photometry example


Consider you are observing a long-period variable star with a magnitude range from 9.7 to 16.9. When the star is near maximum brightness, you need short exposure times and would for instance select 2 reference stars around magnitude 11. When the star is near minimum brightness, longer exposure times are needed, causing the previously selected reference stars to saturate. 


Therefore it would be practical to select 2 bright reference stars for maximum light and 2 faint reference stars for minimum light. Phoranso allows you to create one ID Card for this variable with all 4 reference stars. Using the Enable/Disable for Photometry option, you can easily switch between the bright and faint reference stars depending on the star’s brightness.


Hence, if the variable star dims to near minimum after a few months of observing, retrieve the corresponding ID Card to reverse your selection of reference stars.



Notes

  • ID Cards created with earlier versions of Phoranso will have all reference and comparison stars enabled by default. No modification of older ID Cards is necessary.
  • A Check star cannot be enabled or disabled for photometry as Phoranso requires exactly one enabled check star.