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Big, bright fast mover (7482) 1994 PC1
#32
Phil, you had asked about the differences in position with elements at the beginning of this thread and more recently. I took a look and found nothing significant. I think because we are using the same elements from the MPC with the same epoch, in theory they should look the same. But a closer look shows that due to the adjustment caused by the gravity influence when getting near us, software can make a difference. Or in the case of ST4, the need to massage the inputs. I made a table of positions and all use the MPC except one that can only use Lowell. It was very educational to see the 3 positions in ST4 given a bit of correct input. Three choices - MPC, MPC NEA Daily or Osculating Elements created by Horizons. Lesson is to always use Osculating for NEAs. Although the MPC NEA Daily can be a much faster exercise and nearly as accurate.

All errors referenced Horizons from my location:

Date_CST  _HR:MN          R.A.          DEC               Azi    Elev    APmag    Software           Error
2022-Jan-18 19:00       01 39 14.10 +08 21 03.6   211.08  64.96   10.395  (Horizons)         0.0"
                                  01 39 13.7  +08 21 07.1    212.3    65.16    9.52  (AstroGrav)         6.6"
                                  01 39 13.8  +08 21 09      211.08   64.28  10.3   (ST4 Osc Els)       8.1"
                                  01 39 13.5  +08 21 13      211.08   64.28  10.4   (ST4 MPCNEADy) 14.0"
                                  01 39 23.1  +08 19 53      211.5     64.7    10.4    (MegaStar 5)       2.5'
                                  01 39 27.4  +08 17 30      210.9     65.25  10.4    (SkyTools 4)        4.9'

I was clouded out last night, being only able to spot the fuzzy moon and a couple of bright stars. Strangely, my buddy 25 miles SSW had partial clearing and was able to shoot a series of 30 second images. I'll send a copy when I get it.
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RE: Big, bright fast mover (7482) 1994 PC1 - by bigmasterdrago - 2022-01-19, 03:51 PM

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