[neo_followup] {MPML} Tianwen-1 astrometry/ephemerides

[Patrick Wiggins]

I’m looking for it on JPL Horizon in hopes of imaging it from here at 718.

But I can’t find Tianwen listed.

Is it under another name?

Thanks,

patrick
718

> On 24 Jul 2020, at 08:12, Bill J. Gray <pluto at projectpluto.com> wrote:
> 
> Hi folks,
> 
>   I've received astrometry for a Tianwen-1 object from Masayaki
> Suzuki at (I89) and Guy Wells and Daniel Bamberger at (Z80).  The
> latter posted an image and some info at
> 
> https://twitter.com/NBObservatories/status/1286470009947131904
> 
>   The object has H=27,  roughly what you'd expect for the booster,
> but I'm not entirely that it is.  I'm labelling it as TianweA
> for the moment (MPC frowns on eight-character designations).
> 
>   Cut-and-paste this message,  or at least the astrometry shown
> below,  into
> 
> https://www.projectpluto.com/fo.htm
> 
>   and you can get custom ephemerides for TianweA good to about an
> arcminute.  (We also have some astrometry from ATLAS -- they caught
> the object early on and put it on NEOCP -- but it confuses Find_Orb
> and we really aren't supposed to distribute it anyway... fortunately,
> we don't absolutely need it in this case.)
> 
>   You'll see at the above Twitter post that NBO also spotted a
> second object,  fainter by about three arcminutes,  about 3.6'
> west and 3.6' north.  They got one position,  so this is awaiting
> confirmation;  it might just be an artifact.
> 
>   I also have a report of yet _another_ object,  roughly as
> bright as TianweA,  but about 22' west and 25' to the south.  Not
> enough astrometry for a reliable orbit,  but I think if you look
> at that offset from TianweA,  it should be easy to find.
> 
>   Seems there's been some tracking of the signal from the
> spacecraft :
> 
> https://twitter.com/uhf_satcom
> https://twitter.com/df2mz
> 
>   which suggests to me that we'll be able to figure out which
> is the spacecraft and which is the booster,  and possibly add
> some of their data to the mix.
> 
> -- Bill
> 
> COD I89
> CON M. Suzuki, 9-12-17 Kouei-nishi-machi, Kitami-shi, Hokkaido 090-0058, Japan
> CON  [mtnsuzuki at nifty.com]
> COM Tianwen-1 booster
> OBS M. Suzuki
> MEA M. Suzuki
> TEL 0.15-m f/7.3 refractor + CCD
> ACK I89 ART SAT Tianwen-1 booster 2020-07-24 11:39:00 Suzuki
> AC2 mtnsuzuki at nifty.com
> NET Gaia DR2
> COM =      TianweA
> Tianwen-1     C2020 07 24.09738 00 46 31.26 +14 59 59.3          15.7 G      I89
> Tianwen-1     C2020 07 24.10042 00 46 29.86 +15 00 30.6          15.9 G      I89
> Tianwen-1     C2020 07 24.10354 00 46 28.40 +15 01 02.1          15.7 G      I89
> Tianwen-1     C2020 07 24.10762 00 46 26.39 +15 01 42.7          15.9 G      I89
> ----- end -----
> 
> 
> COM =      TianweA
> # version=2017
> # observatory
> ! mpcCode Z80
> ! name Northolt Branch Observatory
> # submitter
> ! name D. Bamberger
> # observers
> ! name G. Wells
> # measurers
> ! name D. Bamberger
> # telescope
> ! design Ritchey-Chretien
> ! aperture 0.25
> ! fRatio 8.0
> ! detector CCD
> # software
> ! astrometry Astrometrica 4.12.0.448
> ! photometry Astrometrica 4.12.0.448
> permID |provID     |trkSub  |artSat      |mode|stn |obsTime                |ra         |dec        |rmsRA|rmsDec|astCat  |mag  |rmsMag|band|photCat |photAp|logSNR|seeing|exp |rmsFit|nStars|notes|remarks
>       |           |  Probe2|            | CCD|Z80 |2020-07-23T23:42:43.0Z | 11.46081  |+14.40392  |0.23 |0.21  |   Gaia2|15.5 |0.06  |   G|   Gaia2| 7.9  |1.59  |3.9   | 100|0.17  |    74|K    |
>       |           |  Probe2|            | CCD|Z80 |2020-07-23T23:44:23.0Z | 11.46280  |+14.40863  |0.25 |0.23  |   Gaia2|15.5 |0.06  |   G|   Gaia2| 7.9  |1.46  |4.0   | 100|0.19  |    76|K    |
>       |           |  Probe2|            | CCD|Z80 |2020-07-23T23:46:03.1Z | 11.46494  |+14.41339  |0.23 |0.24  |   Gaia2|15.6 |0.07  |   G|   Gaia2| 7.9  |1.46  |4.0   | 100|0.18  |    81|K    |
> 
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