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    The PLATO-Mercury-Test

    Motto: Round the star in 80 days
    Small telescopes help to confirm and decontaminate transits of planets with periods of 40 to 120 days.

    A step towards the detection of a 1-1-1-1-1 planet with PLATO.

    1 Earth radius - 1 Earth mass - 1 year orbit - 1 solar mass star - 1 solar system age

    The next transit-appointments


    Southern Hemisphere

    Auckland, Cape Town, Sao Paulo,


    Helsinki, Munich, Prague, Vienna


    Kuffner-Sternwarte, Ottakring, Lund, Tartu - Univ. Observatory site, Tartu - Meridian Circle (Struve Arc UNESCO World Heritage site)


    Go to ETD-Alerts .

    Your favorite site is not on the list? Contact Verein@kuffner-sternwarte.at and send site details.

    What is needed

    High precision differential photometry of the target star and the nearby stars over a period covering the event - ingress/egress/center - and at least one hour before and after the event in order to well characterise the before/after levels.

    The goal is not a full lightcurve, but a detection of the transit event and possibly a confirmation of its expected properties. That means to collect evidence that the transit is occuring with the expected parameters at high confidence levels. That includes distinction from random (noise) and systematic (contaminants, weather photometric stability) errors.

    Recommended equipment / experience:

    Starting now, selected current planet candidates will be made available at the Exoplanet Transit Database (ETD) listed as planet candidates. ETD provides coordinates, finder-charts, transit- predictions, and a search for transits for given observing location. Results can be uploaded to ETD, including a simple automatic analysis. Directly to the list of ETD-TOI-transits for the next day

    Transiting planets of bright stars, TESS and PLATO

    The PLATO space telescopes are designed to find and measure terrestrial planets with orbits typical for the inner solar system. PLATO will go were its precursors CoRoT an Kepler had to stop. It will measure bright stars, as the NASA mission TESS already does, in search for shorter period planets. This provides a unique opportunity to gain experience with small telescopes, an experience that will be needed once PLATO is in orbit.

    PLATO has a total light collection power slightly larger than NASA's Kepler. But the innovative optical segmentation concept (distribution of light-collection over 2+24 telescopes) allows ist to be applied to a large number of bright stars and thus, for the first time high accuracy determination of stellar properties including ages and an accurate determination of planetary masses for entire systems and planets in the terretrial regime - an Earth mass in Earth-sized orbit around a solar masss star.

    The data obtained will serve the support of TESS and the development of an optimised instrument, the PLATO PlanetValidator, which will be tuned for testing the planet candidates of bright stars. The PlanetValidator will also allow the measurement of the properties of large PLATO-planets with small telescopes.

    PLATO's and TESS' return to the bright stars puts small telecopes back into the focus of astronomy. They allow tests of PLATO and TESS transit-signals: are they "true" planets or "fake" signals?

    The TOI-candidates (TOI = TESS Object of Interest) have been listed by the NASA-mission TESS and they are part of the TESS TOIS release programme. These candidates are signals the are planet-like according to the quick-look of the TESS-team. Some of the signals detected by TESS are due to known planets discovered by the space missions CoRoT, Kepler, K2, and ground based searches as WASP, HAT, KELT, .... . They will not extra added to the ETD as TESS-candidates, but may appear in the transit prediction ephemerides below, marked with their discovery programme (CoRoT, Kepler, ...).

    An explanation of TESS compared to PLATO is available on the PLATO-Consortium-pages.

    ETD Alerts

    TOI 1897.01 on 3rd of June 2023, TOI 1897.02 on June 21st

    Issued June 3rd.
    Dear colleague,
    you are invited to join the  PLATO-Mercury-Test - observation of transit of TOI 1897.01 b on 3rd of June 2023.
    This is another request for observation of a long period transiting exoplanet issued by the TRESCA / ETD 
    project within PLATO GOP - ground based observation programme.
    We are going to take advantage of this unique opportunity to acquire a series of measurements of an event 
    of TOI 1897.01 transit today.
    This is a candidate planet detected by TESS satellite, which data suggest also a second body on the 
    similar orbit around its parent star - the TOI 1897.2. in distance of 1/3 of orbit path, which will 
    be transiting on 21th June, which makes it an interesting object.
    Not many observers will be able to observe complete transit, but even separate observations of ingress 
    and egress are valuable.
    Precise transit observations are important to improve and maintain knowledge of planet orbital 
    properties enabling efficient time-management of further ground and space based observations. 
    Such observations are rare and difficult to perform from the ground, but will be playing an 
    important role as follow up of the ESA PLATO mission.
    The objects and transits:
    TOI 1897.02  | RE: 03 13 28.90 | DE: +75 16 06.16 | Mv = 10.6 mag | T14 = 6.14 hours | Depth = 5.1 mmag |
    Ingress: 2023-06-03 17:30 UTC (observable: Asia)
    Egress: 2023-06-03 23:38 UTC (observable: Near East, Europe)
    TOI 1897.01  | RE: 03 13 28.90 | DE: +75 16 06.16 | Mv = 10.6 mag | T14 = 6.66 hours | Depth = 65.5 mmag |
    Ingress: 2023-06-21 15:26 UTC (observable: Central Asia, India, Eastern Asia, Pacific)
    Egress: 2023-06-21 22:05 UTC (observable: Europe, Near East, Central Asia, India) 

    Previous appointments

    GW on request from the Filip Walter / ETD

    HD 80606 / HIP 45982: Ingress: 2023-02-26 15:50 UTC, Egress: 2023-02-27 03:43 UTC

    More on the HD 80606 / HIP 45982 February 26th transit:

    Kepler-1514b from 16th to 17th May 2023

    More on the ~ 220 d Period transit:

    Impressum und Datenschutzerklärung: Verein Kuffner-Sternwarte, 2023-09-16, Ephemerides updated; GW 2023-08-26, GW