Orbit Determination & Position Prediction


There are two minor body position determination tools on this page: Vaisala Orbit Determination and Predict. The one that you should use is based on a couple of factors. If you are tracking a potential discovery and you have only one night's worth of observations, use Predict to determine the approximate position of the body for a future date. You must have at least two observations for Predict, but more is better. The prediction date should be within a few days of the last observation for the best accuracy.

Use Vaisala if you have two or more observations spread over several nights. The Vaisala method is most accurate when there are a couple of days between the observations. However, if the minor body is fast moving, such as a close approach, Predict will likely be more accurate. If the object is known, use the Minor Planet Center's, Minor Planet & Comet Ephemeris Service for the most accurate position on a given date. The Vaisala results include prelimnary orbital elements.

The date fields represent the prediction date. The text area is for entering your observations. Observations can be entered in two formats: A properly formatted MPC observation like you would submit in a report to the Minor Planet Center or a comma delimited list of observations "date, ra, dec" in that order. Observations must all be of the same type! For comma delimited observations, the date must be in FITS format i.e.(yyyy-MM-ddTHH:mm:ss.SSS). If you don't have the precision for fractional seconds, enter 0's for the three decimal places i.e.(2018-03-25T01:29:49.000). RA and DEC may be entered in decimal or sexagesimal form and RA is in 24 hour format. Only one observation per line and observations must be in chronological order.


Examples of 80 column MPC formatted observations:

03122         C2017 09 16.08381 18 53 01.48 +65 18 00.4          12.1 V      H32
     MC002  * C1999 10 03.03750 20 19 04.81 -18 06 43.4          19.3 V      740

Examples of comma delimited observations:

2018-03-25T01:29:49.000,07 46 42.480,+22 03 12.815
2018-03-25T01:29:49.000, 07:46:42.480, +22:03:12.815
2018-03-25T01:29:49.000,07h 46m 42.480s,+22d 03' 12.815"

Month Day Year Hour Min Sec