2020-06-24, 03:09 AM
So, 24 hours from now a rock from space will pass just outside the orbit of the Moon. I downloaded the MPC NEA Today rocks and searched and excepted the 2020 MP1 data. I set the starting date for 24 hours in the future 2020 June 24 21h00m to run the position ephemeris over a period of 6 hours in one hour steps. I got the output in the image. There is a small green filled circle at the bottom left corner that blinks red??? I was going to print a finder chart but the positions are well off from those produced by Horizons -- 2020-Jun-25 04:00UT RA 19 43 52.54 DEC -06 22 39.1 Mag. 14.507 Horizons will not print finder charts. See my attached field chart where I hand plotted the positions given by SkyTools 4g (S), Horizons (H) and plotted by another popular program with the local CDT of all the positions. Taking Horizons as the gold standard, I find the SkyTools position 52 arc minutes WNW and the other software well over a degree too far NW. What can I do to improve the plotting on the Interactive Atlas if the position ephemeris is not correct? Should I create an IA with a Skymark at the several Horizons positions?