0
Fixed

Inaccuracy in the description of the positional error in the Chandra catalogue.

Ricardo Pérez Martínez 1 year ago • updated by anonymous 1 year ago 3

In the description of the Chandra catalogue, the column related to the positional error is defined as 

Position error radius at 95% confidence level   //  arcsec   // Position error 95% confidence level circle radius (column also called err_ellipse_r0)

While in the Chandra web page, err_ellipse_r0  is said to be something different

Three of the parameters specifying the geometry of each error ellipse are the semi-major and semi-minor radii (/err_ellipse_r0/, /err_ellipse_r1/), and the position angle θ that the major axis of the ellipse makes with respect to the tangent plane /y/ axis (/err_ellipse_ang/).

What is not actually the same. The difference can be specially relevant when cross matching several set of catalogues/source lists at once.

Answer

Answer
Fixed

Dear Ricardo,

We are happy to report that the problem you reported has been fixed in version 2.0 of the ESASky application: http://sky.esa.int

Enjoy!

Bruno

on behalf of the ESASky team

Thanks Ricardo,

We have already fixed the documentation and the column in the application will be updated with version 2.0, to be released on the 24th of October of 2017.

Cheers,

Bruno

Answer
Fixed

Dear Ricardo,

We are happy to report that the problem you reported has been fixed in version 2.0 of the ESASky application: http://sky.esa.int

Enjoy!

Bruno

on behalf of the ESASky team