Transform Generator not working as expected

Mon, 07/05/2021 - 17:31

I am trying to calculate transform coefficients for a color ZWO camera using VPHOT and TG. 

TG ran properly using the demo file so I know that it is working on my computer. The calculations took a couple of seconds.

I have a calibrated and stacked image of M67. I separated the color channels and uploaded them to VPHOT using the filter names V, B, and R.  I followed the instructions provided in the posting from this March entitled "New VPHOT workflow to simplify prepping data for TG".  In VPHOT it went as expected and it generated a report file titled "HW+CnC.txt". 

However, when I opened TG, set up a 'telescope', selected the file with my data, clicked on "TG/AIP", and clicked on Calculate Transform Set, it produced no result.  Not even an error report. I did that several times, repeating the entire process from start to finish.

Then, I went back to VPHOT and downloaded photometry reports separately for each of the three filters.  This time I selected my three data files and chose "VPHOT", I got the same result ... no results displayed and no error messages.

I am clearly doing something wrong, but I do not know what to do next.

Any suggestions?


ps.  I tried to attach the HW+CnC.txt file to this posting, but in the "File Upload" feature, the 'Add a new file' window was greyed out, and would not let me add the file.

American Association of Variable Star Observers (AAVSO)
VPhot/TG workflow issues

Hi Rick,

Share your M67 images on VPhot with me, user SGEO.

Also please send that HQ+CnC.txt file to me at

I'm sure we can get this sorted out. And maybe improve the instructions of the new workflow at the same time!