ssystem_1000comets.ini contains comets already in default ssystem_minor.ini

[Atque]

The ssystem_1000comets.ini contains a few comets already present in the ssystem_minor.ini, leadning to ugly doublets in the sky when the former is loaded.

A few comets that appear as doubles:
C/1995 O1 Hale-Bopp
C/1996 B2 Hyakutake
C/1680 Kirch

The fastest solution to this is to either delete those from the file completely, or comment them out so they're not loaded. It's tedious but very easy to do.

[gzotti]

Kirch should clearly not be in ssystem_minor.ini. I am less sure about which file is better for the Great Comets of our lifetimes. But I have not checked, are the ini keys different? Else I would expect an existing object is just replaced.

[Atque]

Maybe historical comets (older than an average lifetime of ~80 years, i.e. no one can remember seeing them) could be moved to the historical comets file. Bright ones in living memory such as Ikeya-Seki could thus remain, but must be removed from the historical file.

I also think Neowise of 2020 could be added to the main ssystem_minor. Loading it from MPC gives epoch of today, making it inaccurate.

[gzotti]

Yes, fetching current data with current epoch from MPC is useless for past comets simulated near the perihelia. I have some old files with Neowise (2020F3) with epoch >1 year after perihel, and some experiments with no epoch. (Did this comet pass earth?) Do you have a good element set with epoch near perihelion?

There are a few possible thresholds:

• 1970 UNIX era
• 1980 just because
• 1986 Halley
• 2000 project begin
• 5 years ago, and periodically move older "greater comets" to the historical file.

Does anybody keep an archive of older elements? What would be needed are elements for near-perihel epochs for the past 20 years or so. And I still need to add some data to the old elements file before recreating 1000_comets.ini... And we should define criteria for inclusion to the historical comet file.

[Atque]

There are Neowise orbital parameters from the epoch of perihelion here:
https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2020F3