2024-04-05, 03:40 PM
Phil,
In the thread above there has been some confusion about what data you were asking about. We were mostly discussing using the Bright Minor planet download from the MPC as compared to the other MPC sources. I didn't see a specific question that I understood to be specifically about my curated current minor planets list until just now.My Current Bright and Interesting Minor Planets uses data from ASTORB, which usually has data at more recent epochs. ASTORB used to be updated daily, which was awesome, but that went away some time ago. I have found significant differences in the position of main belt asteroids at opposition using the the data from the MPC. If I were them I'd be embarrassed. This is because their epochs are too far apart in time. Osculating elements are only really good for 90 days or so, especially for a main belt asteroid near opposition because they are relatively close and move quickly. For this reason I use the ASTORB elements instead for my list. They are available to everyone via the ASTORB download rather than the MPC.
You can easily tell where the elements came from. Open the Osculating Elements dialog and look at the Source field. It will say "Lowell" if it comes from ASTORB. Some of these will be out of date simply because they are no longer at opposition or bright enough to be included in my list. They aren't updated year round, only those in the current list get updated that month.
The Current list is there for casual observers so they have an easy way to add a bright asteroid to their list, and so that the NOLG will have enough data to suggest one or two. For people who want to observe asteroids and minor planets more deeply, the next level up is to download the Bright Asteroids from the MPC frequently.
The MPC gets funding for near earth asteroids, and that is a huge computational effort, so for your close approaches they can have have better data then ASTORB, and as you know JPL has even better elements than that. But for these bright man belt asteroids, they do have orbits that change, and the MPC just doesn't keep up with them.
In the thread above there has been some confusion about what data you were asking about. We were mostly discussing using the Bright Minor planet download from the MPC as compared to the other MPC sources. I didn't see a specific question that I understood to be specifically about my curated current minor planets list until just now.My Current Bright and Interesting Minor Planets uses data from ASTORB, which usually has data at more recent epochs. ASTORB used to be updated daily, which was awesome, but that went away some time ago. I have found significant differences in the position of main belt asteroids at opposition using the the data from the MPC. If I were them I'd be embarrassed. This is because their epochs are too far apart in time. Osculating elements are only really good for 90 days or so, especially for a main belt asteroid near opposition because they are relatively close and move quickly. For this reason I use the ASTORB elements instead for my list. They are available to everyone via the ASTORB download rather than the MPC.
You can easily tell where the elements came from. Open the Osculating Elements dialog and look at the Source field. It will say "Lowell" if it comes from ASTORB. Some of these will be out of date simply because they are no longer at opposition or bright enough to be included in my list. They aren't updated year round, only those in the current list get updated that month.
The Current list is there for casual observers so they have an easy way to add a bright asteroid to their list, and so that the NOLG will have enough data to suggest one or two. For people who want to observe asteroids and minor planets more deeply, the next level up is to download the Bright Asteroids from the MPC frequently.
The MPC gets funding for near earth asteroids, and that is a huge computational effort, so for your close approaches they can have have better data then ASTORB, and as you know JPL has even better elements than that. But for these bright man belt asteroids, they do have orbits that change, and the MPC just doesn't keep up with them.
Clear skies,
Greg
Head Dude at Skyhound
Greg
Head Dude at Skyhound