Downloading the Data
We’ve rolled out a new feature to the site. You now have the ability to download the lightcurve data directly from Planet Hunters. Once you’ve classified a star and submitted the transits, the download data button will appear and is available for every star on its source page (ie http://www.planethunters.org/sources/SPH10067557) as well as from the user My Star page (http://www.planethunters.org/profile) where you can download the data for all the stars you’ve classified (we’ve now paginated the My Stars page so all your favorites and all the stars you’ve classified should now be listed).
The file is in CSV (Comma-Separated Values) format which can be opened directly or imported into Excel, Numbers or the Open Office equivalent where you can then plot and manipulate the data. We provide additional info about the star properties including infrared color, specific gravity, right ascension and declination, and Kepler IDs. We also identify if the star is a Simulation (simulated transit lightcurve), a Kepler Planet Candidate (ie Kepler Favorite -a star that the Kepler team believes has a transiting planet but has not confirmed with follow-up observations) or Source (real Kepler lightcurve). For the simulated lightcurves, the CSV file will provide the planet radius in Earth radii and orbital period in days for the injected transit signal (assuming the given radius of the star).
The CSV file also contains three columns of data labeled time (days), brightness, error in brightness. The brightness values are the brightness of the star measured by Kepler per observation corrected for instrumental effects and systematic errors by the Kepler Team’s data processing pipeline. The error in brightness is simply +/- error in the reported brightness measurement. We’ve normalized the brightness values by dividing what we get from the Kepler public release data by a constant value just for convenience, so it’s easier to measure relative change in the brightness of the star. This just shifts the absolute value of the y-axis up or down for our plotted lightcurves but doesn’t change the actual depths of any transits. For more specifics about the data, see the Corrected Light Curves section of http://keplergo.arc.nasa.gov/DataAnalysisProducts.shtml.
Some times there’s a missing data point in the lightcurves the Kepler Team has released. These missing data points indicate a”no data” condition where the observation has been compromised by spacecraft operations or other anomalies that effect the quality of the measurements (examples might be the spacecraft entering safe mode or possibly a glitch with the electronics that readout for the flux measurements for that star). To indicate those data points we’ve set the brightness value to zero in the CSV file.