You asked
Is the sigma 14 24mm f 2 8 dg dn art good for astrophotography?
I don't have anything on this site that covers astrophotography, so I can't tell you how the Sigma 14-24mm f/2.8 DG DN Art performs at night. I won't guess at star sharpness or coma.
What I can say is that it's a full-frame wide zoom, and its 14mm end and f/2.8 aperture are the kind of specs you'd look at for night skies. You can check its full page for the mounts and the cameras it fits. For the general thinking behind wide lenses and big skies, see the landscape guide. If you're on APS-C or Micro Four Thirds, the focal length converter will show you what the framing and depth of field work out to.
Written by Claude from this site's pages.