Search for HD 156846b transit

VALIDITY: 23. 8. 2011 - 25. 8. 2011
AUTHOR: Gregory Laughlin, 10. 8. 2011
 
Dr. Gregory Laughlin have recently announced an upcoming transit window for possible occultation of 359.6 d orbiting planet b arround parent star HD156846 (Oph). After 2007s HD17156 b and 2009s HD80606 b transit detection, here is another change to catch a long period transiting exoplanet from the ground.

Star parameters:
name: HD156846
coordinates: RA: 17 20 34.31, DE: -19 20 01.5
constellation: Oph
brightness: V = 6.5 mag
spectrum: G0

Planet parameters:
orbital period: 359.6 days
eccentricity: e = 0.848
predicted transit depth: 0.003 mag

When to observe:
During days: August 23rd, 24th, and 25th
S. R. Kane et al. (2011) have predicted transit event with high accuracy to
begin at 2011-08-23 21:25 UT (JD 2455797.39) with
midtransit at 2011-08-24 02:12 UT (JD 2455797.59)
ending at 2011-08-24 06:59 UT (JD 2455797.79).
Accuracy +/- 20 minutes.

Comparison stars:
Observers should use comparison stars of the same color as the target object to prevent systematic trends in the data.
We recommend to use comparison star:
HD157172, V=7.85, G5 about 0.5 deg far from the target
Observers with larger field of view (smaller telescopes) may use close bright star HD157546, V=6.33 mag, A0. This comparison star is of different spectral type, so we prefer to use the first one mentioned above.







Where to post data:
All your photometry should be uploaded to TRESCA Observers log. Please use the target name HD156846 and observers project TRESCA while uploading the data. All data will be agregated there and everybody can see the joined results at the page:
http://var2.astro.cz/EN/obslog.php?obs_id=1&projekt=TRESCA&star=HD156846
HOW TO START TO USE Observers log:
1) Sign in to the var2.astro.cz server.
2) Click to link Observers logs
3) Click to Insert new data (Type object name HD156846 and observer project TRESCA)
4) With first data, your observer's log will be created.
5) All your questions can be sent to brat@pod.snezkou.cz


More information:
Be sure to check back at oklo.org and to follow twitter.com/transitsearch for updates and interesting details as this opportunity draws near!