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Comet 46P/Wirtanen data are not up to date

I'm using SkySafari 6 PRO (Mac version). Looks like 46P/Wirtanen data downloaded today refer to 7/7/2018 and this causes a slightly difference between actual and predicted position. Stellarium uses the same data taken from IAU Minor Planet Center and gives the correct position with respect to the images I'm taking these days.

These are the most recent data available from IAU. Note epoch (20181207)

0046P         2018 12 12.9282  1.055359  0.658704  356.3359   82.1590   11.7471  20181207  14.0  6.0  46P/Wirtanen                                             MPEC 2018-W59

that are different from data available in Skysafari after an update. Orbit elements are still referred to 20180707.
Can you please check?

Alberto Cavalli

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7 comments

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    Bill Tschumy

    Yes, was just looking at this.  That is the latest data that we download from JPL.  Not sure why they haven't publish more up to data elements.

    It is only off by about 0.5º, so I don't think it will cause anyone to miss it.

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    Bryn Owen

    Alberto / Bill,  may I ask a follow up question to this please? ...

    When I select 46P/Wirtanen, and right-click "orbit" it, and then zoom away from it a few hundred thousand km to get a view of the solar system, as I forward through time the comet never orbits the Sun!  I have changed angles and zoom levels, and it never goes around the Sun at all!  In fact it approaches Earth then starts to travel away.

    ie:  the orbit of this comet is completely wrong!

    Thank you,
    Bryn

     

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    Bryn Owen

    So sorry about my recent question - it was a graphical phenomenon making it appear as though the orbit "avoided" the Sun, but it does not in fact.  Once I moved to a better perspective it became clear that the orbit is correct.  Helps to also enable the orbit for the selected object!  -Bryn

  • 0
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    Bill Tschumy

    Alberto,

    We have just made a change to our data update.  The new orbital elements for Wirtanen are Dec 7th, 2018.  This should give you a more accurate position.

  • 0
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    Alberto Cavalli

    Nice job, thank you. I'm using Skysafari to point objects with a narrow field camera and now it works like a charm. 

  • 0
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    Bill Tschumy

    Thanks.  Unfortunately, I notice that while the position is accurate, it is now showing the comet at mag 8.9.  This is not our bug but it is unfortunate.  If you go to the Minor Planet Center and generate an ephemeris for 46p, that says the comet is 8.9 as well.  So it is a glitch in their data, not us.  Not much we can do about that.

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    Alberto Cavalli

    Luckily it's a minor issue. Somebody's still celebrating Insight's landing maybe :)

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