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No comparison stars for HAT-P-36 b

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nekkar's picture
No comparison stars for HAT-P-36 b


I observed a transit in HAT-P-36 b and sent it to ETD but now I found no comparison stars to send absolute photometry to AAVSO.

How can I ask for at least one comparison star for Johnsons V filter ?

Thank you in advance.


res's picture
No comparison stars for HAT-P-36 b
dennis-conti's picture
Comparison stars for exoplanets

Hi Mario,

There is no need for exoplanet observations to get absolute photometry - everything is based on the relative difference in flux (magnitude) between the target star and multiple comparison stars. See my "Practical Guide to Exoplanet Observing" that can be found at Feel free to contact me off-forum at if you would like further clarification.


AAVSO Exoplanet Chairman

nekkar's picture
Exoplanets photometry

Thanks Res and Dennis for the answers.
My observations are sent to ETD as relative photometry, but I ask the question because I have seen in AAVSO that two observers of this exoplanet have used comparison stars, chosen personally. That's why I believed that absolute photometry was now a must.
According to what Dennis says, the exoplanets will be sent to AAVSO as relative photometry, and I'll real your guide too !!!

Best regards.


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