[Aavso-photometry] RE: Final reduction of TrES-1 transit observations

[Arto.Oksanen at tietoenator.com]

Dear all,

Congratulations for a great observation, Tonny! 

We are planning a follow-up observation tonight in Finland (weather permiting). At least our 40 cm telescope and the 50 cm telescope of Jakokoski observatory will try to observe. Others are welcome to join the campaign to derive good timing of the transit. Larger telescopes should use V filter for easier calibration. 

best regards,

arto

--
Arto Oksanen                         arto.oksanen at jklsirius.fi
Jyvaskylan Sirius ry, Kyllikinkatu 1, FI-40100 Jyväskylä, Finland 
Tel: +358-40-5659438                         Fax: +358-14-4157803
Nyrola Observatory  http://www.ursa.fi/sirius/nytt/nytt_info.html 

-----Original Message-----
From: aavso-photometry-bounces at mira.aavso.org [mailto:aavso-photometry-bounces at mira.aavso.org] On Behalf Of Tonny Vanmunster
Sent: 4. syyskuuta 2004 3:30
To: cba-news
Cc: Aavso-Photometry; vsnet-obs
Subject: [Aavso-photometry] Final reduction of TrES-1 transit observations


Dear colleagues,

I herewith include updated information on my transit observations of
exoplanet TrES-1, dd September 1st, 2004. The article featured on the
Sky&Telescope website shows a picture of my raw (unprocessed) transit light
curve, that 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 on my web
site (www.cbabelgium.com). 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.

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)

Tomorrow brings another opportunity over Europe to observe a transit of
TrES-1. It would be interesting to learn about follow-up observations, and
to see if the above statements regarding ingress/egress time differences are
confirmed.

Best regards,
Tonny

Tonny Vanmunster
CBA Belgium Observatory
http://www.cbabelgium.com
________________________________________________________
PERANSO : The Final Frontier of Period Analysis Software
http://www.peranso.com
________________________________________________________



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