View Issue Details
|ID||Project||Category||View Status||Date Submitted||Last Update|
|0002135||SkyChart||1-Software||public||19-05-17 15:21||19-08-14 13:48|
|Reporter||Birger||Assigned To||Patrick Chevalley|
|Platform||PC||OS||Windows||OS Version||10 64bit|
|Product Version||4.1 SVN|
|Target Version||Fixed in Version|
|Summary||0002135: Impossible to get older asteroid elements|
|Description||It seems impossible to get older asteroid data. Setting the year to e.g. 1998 and displaying asteroids, CdC asks you to download an MPC file, which is understandable as the current ephemeris is not accurate. When the file is downloaded, it asks you to prepare monthly data. However, it then says to download an MPC file, and it starts all over again. Seemingly, it is impossible to display accurate asteroids in the past.|
Is it a bug or am I misunderstanding something?
|Steps To Reproduce||1. Start CdC.|
2. Set the year to e.g. 1998.
3. Display asteroids. An error message will show.
4. Go to Setup > Solar System > Asteroids > Load MPC file
5. CdC now asks you to prepare monthly data. However, this will fail and CdC will ask you to download a new MPC.
|Tags||No tags attached.|
It is not easy to get old elements.
To my knowledge the MPC web site do not offer this possibility at all, so CdC cannot download automatically the elements for the date you set, but only the most recent elements.
Do you know a place this old elements can be downloaded?
The only way I know is to request the elements for one asteroid at a time from the JPL Horizon web interface.
This method is described here:
||Unfortunately, no. However, it seems the Occult software found here http://www.lunar-occultations.com/iota/occult4.htm uses old MPC's. At least its asteroid ephemerides seem accurate even in the past.|
I cannot look how Occult do it because it is not open source.
Also CdC need a way to do bulk calculation of all know asteroid, not only a specific one.
For now I don't know how to do that.
The only solution, valid for the future is to archive the MPC file once a year.
I find a few one since 2011 on my computer and I setup a crontab to save a new file once a year.
They are available here:
|19-05-17 15:21||Birger||New Issue|
|19-05-18 14:46||Patrick Chevalley||Assigned To||=> Patrick Chevalley|
|19-05-18 14:46||Patrick Chevalley||Status||new => feedback|
|19-05-18 14:46||Patrick Chevalley||Note Added: 0005651|
|19-05-19 16:01||Birger||Note Added: 0005652|
|19-05-19 16:01||Birger||Status||feedback => assigned|
|19-08-14 13:48||Patrick Chevalley||Status||assigned => resolved|
|19-08-14 13:48||Patrick Chevalley||Resolution||open => not fixable|
|19-08-14 13:48||Patrick Chevalley||Note Added: 0005853|