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Ursa Astronomical Association
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00130 Helsinki

Ursa Astronomical Association

Exoplanet HAT-P-17b - 19.9.2020 at 21.00 - 20.9.2020 at 01.00 Kirkkonummi Observation number 93896

Visibility III / V

Teemu Willamo, Tuomas Salo, Ursa (Helsinki)

We detected an overflow of the exoplanet HAT-P-17b from the Metsähovi Observatory of the University of Helsinki in Kirkkonummi. The overpass began very soon after dark, so we were in a hurry to find the destination, and we were a few minutes late from the predicted start of the overpass.

The figure below shows the brightness of the parent star HAT-P-17 in magnitudes relative to the two reference stars. A clear dimming lasting about 4 hours can be seen as the planet passes in front of the parent star. Some strange throw is also noticeable, which may be due to us focusing the image somewhere new after a little change in conditions, but there could also be some real changes in brightness, as the changes appear very similar regardless of which brightness the reference star compares to.

In the picture, the time is in seconds, so that 0 seconds is at 21:00.

In the second figure, an image field where the HAT-P-17 is marked in green and the reference stars used are marked in red.

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Additional information
  • Observation target
    • Exoplanet
  • Designation
    • HAT-P-17b
    • Keskitaso
  • Constellation
    • Cygnus
  • Brightness in magnitudes
    • 10.5
Technical information

The observation tool is Metsähovi's 60 cm Ritchey-Chrétie telescope and ATIK383L + CCD camera without filter. Exposures are all 20 seconds.

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