Doubts about charts without comparison stars

American Association of Variable Star Observers (AAVSO)
Mon, 11/27/2023 - 19:11

Hi, I have a couple of questions about charts for eclipsing binaries that have no photometry table obtained using the Variable Star Plotter. I don't know if this is the best forum to ask this question, but I hope you can help me.

When I use a program like Tycho Tracker, it suggests a series of comparison stars whose photometry is obtained from the Atlas catalog, which is the one I have selected. I usually use 4 or 5 comparison stars that have no brightness variation along the time series of images. In this way the light curve of the eclipsing binary can be obtained.

However, if I want to work in another way, using a calibration star and a comparison star, and the AAVSO chart does not offer comparison stars, I have thought that I could use some of those proposed by Tycho Tracker, but my doubt is how to identify them and which photometry to use. Regarding the photometry, can I use the one proposed by ATLAS or should I use APASS?, the truth is that there is little difference.  But regarding the identification of the calibration and comparison stars, which would be the most appropriate? 2MASS for example or is it better to use the identification coming from another catalog?

I await your answers.

Thanks in advance.