Transit Observations of Exoplanet TrES-1 

I herewith include updated information on my transit observations of exoplanet TrES-1, dd September 1st, 2004. Full details on the observation are given in an article, featuring on the Sky & Telescope website. That includes a picture of the raw (unprocessed) transit light curve, that I initially obtained. It was based on a single comparison star.

Meanwhile, I have used the technique of ensemble photometry (using 7 comparison stars) to increase the accuracy of my observations. This has resulted in a better photometric light curve, which is reproduced below. Each data point or bin is the average value of 5 subsequent CCD measurements. Also shown is the standard deviation per bin. Overall, I obtained a photometric accuracy of 0.003 mag.


Photometric light curve of the TrES-1 transit observation dd Sep 1, 2004
(c) Tonny Vanmunster, CBA Belgium Observatory


Based on the improved data, I furthermore derive :

- magnitude drop : 0.025 mag

- time of ingress (heliocentric) : 2004, Sep 1 at 21h23m UT +/- 2 min (about 10 min later than the transitsearch ephemeris)

- time of egress (heliocentric) : 2004, Sep 1 at 23h50m UT +/- 3 min (about 4 min later than predicted)

- duration central transit : 147 min (published value : 152 min)





Copyright © 2004 - Tonny Vanmunster.