asteroid (70401) davidbishop - check residuals

Alessandro Feb 2, 2013

I think I found a 1950 DSS precovery image of this asteroid.
When I used Find_Orb to check the residuals of these observations, I got a reasonable result: they were well below 0".5, and the overall mean residual was 0".784

So I sent the measurements to MPC and apparently all was fine, the observations appear in the MPC database.

However, yesterday I realized that the 1950 observations are not used in the orbit calculation because their residuals are incredibly high.
MPC calculates:

19500422 675(29.6- 10.2+)
19500422 675(29.6- 10.3+)

I can not understand this.
Did I make a big error when using Find_Orb?


Best wishes,
Alessandro Odasso