Phoranso uses the UCAC4 catalog both for astrometric measurements to calculate the position of the stars in your images and for photometric measurements to extract precise brightness information in various wavelengths (bands) for stars in your images. 



UCAC4 star catalog is not present on your PC


  1. When launching Phoranso for the first time it will notice that you have no UCAC4 star catalog on your PC. It will display the below message, allowing you to directly install the UCAC4 catalog. Press Yes to install.



  1. You will then see the below message informing you that the UCAC4 download involves approx. 12.5 GB of data. Depending on your Internet bandwidth it may take between 15 and 50 minutes or so to complete. Press OK to start the installation (or Cancel to bypass). 


While the installation is ongoing you will not be able to interact with Phoranso. Each time a new UCAC4 file has been downloaded to your PC, you will see a short message appearing in the dialog box. Notice that some UCAC4 files are extremely large, so it can take a long time between successive message updates. 



  1. When the installation on your PC has completed, the below message appears:



  1. You should now proceed to the next section Customizing your Phoranso Settings



UCAC4 star catalog is already installed on your PC


  1. If the UCAC4 star catalog is already present on your PC, Phoranso may still show the above installation message. Ignore it by clicking No.


It then displays the following message allowing you to specify where Phoranso can find the UCAC4 star catalog. Press OK to close the box and follow the below instructions.



  1. Go to the File menu and select Settings . It shows a dialog box where you have to select the Catalogs tab as shown in this image:



  1. In the upper part is a section Photometric Catalog where you can specify the location of the UCAC4 Folder on your PC. Click the button with the 3 dots next to the UCAC4 Folder location field. This brings up a Windows folder selection window. Navigate to the folder on your PC and click OK. The location field will be updated. You can close the Settings dialog box as the changes are automatically saved to your PC.



Important

You have to ensure that your already installed UCAC4 catalog has the exact same structure as shown in the image below.  Your u4b subfolder has to contain exactly 900 items, while the u4i subfolder has only 1 item (file u4index.unf). If your UCAC4 installation deviates from this structure, you will have to go through the above installation step to ensure proper working of Phoranso.