2023-01-31, 06:15 PM
Greg is suggesting adding the ability for ST4 to read a datafile of element sets in the HORIZONS format. You could select the interval between the sets, 1, 2, 4, 6, 12, 24 hours, for example in HORIZONS. ST4 would then use the elements closest in time for calculation of the positions. This is a fantastic option. It would give SkyTools the ability to make more accurate position predictions using osculating elements rather than needing to perform calculations using the equations of motion with perturbations as CNEOS does.
To clarify, the MPC has elements for the NEOs in datafiles for each day ±15 days around today's date. This option could be used to calculate ephemerides using elements 2 days in the future, for example. This is similar to what you can get using HORIZONS, but here you're limited to 1 day intervals. On the plus side, you get the elements for ALL of the NEOs for that future (or past) date. This capability would be most useful while screening the NEOs for upcoming close approaches to observe. In my case I use ST4v's DBPS function to search for MPs that will be within 0.05 AU 2 days in the future, then calculate the ephemeris for each MP to see if it will be bright enough to observe in the 13" scope.
Having both of these functions would be great for asteroid hunters. Getting the MPC's elements for a future date would be great for screening all of the NEOs, then the datafile of HORIZONS elements could be used to calculate the positions during the close approach. Since ST4v reads the HORIZONS datafile, you wouldn't need to edit the MP DB for each element set during the pass - super cool!
I'm looking forward to this update,
Phil S.
To clarify, the MPC has elements for the NEOs in datafiles for each day ±15 days around today's date. This option could be used to calculate ephemerides using elements 2 days in the future, for example. This is similar to what you can get using HORIZONS, but here you're limited to 1 day intervals. On the plus side, you get the elements for ALL of the NEOs for that future (or past) date. This capability would be most useful while screening the NEOs for upcoming close approaches to observe. In my case I use ST4v's DBPS function to search for MPs that will be within 0.05 AU 2 days in the future, then calculate the ephemeris for each MP to see if it will be bright enough to observe in the 13" scope.
Having both of these functions would be great for asteroid hunters. Getting the MPC's elements for a future date would be great for screening all of the NEOs, then the datafile of HORIZONS elements could be used to calculate the positions during the close approach. Since ST4v reads the HORIZONS datafile, you wouldn't need to edit the MP DB for each element set during the pass - super cool!
I'm looking forward to this update,
Phil S.