Type of Object:  The center of the Milky Galaxy probably contains a supermassive (several million times the mass of our sun) black hole.  The  galactic center is called SGR-A*.  The area surrounding SGR-A* contains emission of light from across the electromagnetic spectrum.  The center is obscured by dust clouds in the interstellar medium - so most of our observations are made in the near-infrared and radio parts of the spectrum.

Distance: 26,000 light years
Size: About 100 lyr across, depending on what part of the spectrum you are observing in.
Coordinates (Epoch J2000):
         Right Ascension:        17 45 12
         Declination:                -28 43 00.0

Other Names: Galactic Center, W 24

Radio Brightness at 1420 MHz (21 cm): 2000 Jy

Some Links
http://cfa-www.harvard.edu/~reid/sgra.html
http://chandra.harvard.edu/photo/cycle1/sgr_a/

Imagesshown below, at different wavelengths, cover a
1.0 degree x 1.0 degree area of the sky centered on the nebula.  The images are taken from the SKYVIEW Virtual Observatory maintained under NASA ADP Grant NAS5-32068 with P.I. Thomas A. McGlynn under the auspices of the High Energy Astrophysics Science  Archive Research Center (HEASARC) at the GSFC Laboratory for High Energy Astrophysics. SKYVIEW contains catalogs and surveys from x-ray to radio observations. The site is located at http://skyview.gsfc.nasa.gov/