Sat, 01/09/2021 - 10:22
Dear all,
I am new to vphot, and I am asking a question about fwhm value on the img in joined file.
It seems to me that the value fwhm of 1,77 is for the radius not the diameter of the star
You could see on the image that the star expands on about 3,5 px not 1,77.
It is an important value as the function analysis asks for a value ".... times fwhm" and for the understanding of the values...
Thanks
Jean
Jean,
You are correct. VPhot uses the number of pixels in the radius to describe the FWHM, not the diameter. I think this is a common source of confusion for new VPhot users, especially since the AAVSO CCD Photometry Guide (and most other discussions on this subject) uses diameter.
Phil