Understanding and Creating an O-C Diagram

[oliviam212]

Hello,

I am doing research and I was told that I need to create an O-C diagram for an eclipsing binary. Unfortunately, I haven't been given too much instruction on how to do this. Right now, all I have are minimum times of light, the period of the system, and cycle numbers. I know that O-C is observed minus calculated, but I am not sure what is observed and what is calculated. All that I do know is that O-C is measured in days. Also, I am not sure what to put on the vertical axis (I saw that some O-C diagrams have JDs). Thanks for your help. I am extremely new at the research process.

 

[jedishrfu]

Perhaps this article will help:

http://vs-compas.belastro.net/bulletin-pdf/article/3-8.pdf

and some excel spreadsheet examples:

http://www.aavso.org/bob-nelsons-o-c-files

 

[oliviam212]

Thank you. My adviser explained it more to me, and this helped!

 

[oliviam212]

So maybe I do not know what I am doing. My graph's are not turning out the way they should. What I did was find a calculated HJD by using the period of my graph, the cycle number that I found, and the HJDnaught. I did in fact get mostly different HJD calculated than HJD observed, but they do not match O-C numbers that other people have previously published... My problem is that some of the O-C numbers are not published so I have to find them.