if it is just below the celestial equator, an angle from the celestial equator that increases with latitude. Polar mounts have mechanisms that allow the dish to be tipped down in a permanently fixed angle to match the declination angle. Mounts may also have a variable declination control to allow them to point at geosynchronous satellites in inclined orbits since those satellites have a constantly changing declination. (Adding such a declination axis to a polar mount results in an equatorial mount). Declination offset Because satellites toward the Eastern and Western sky are further away from the observing antenna, there is a change in the declination angle: towards the eastern and western limits the satellites get closer to the celestial equator because they are further out along the lines of perspective. To aim at this apparent shift in the arc of geostationary satellites polar mounts incorporate a slight offset in the angle of their polar axis towards the equator, called a declination offset, to more closely follow this arc. Slewing around a fixed axis which is not parallel with the earth's rotation axis causes the dish to aim at a track in the equatorial plane which is (unless the dish is on the equator) an ellipse rather than a circle. Since the geostationary orbit is circular, the mount does not aim precisely at satellites at all longitudes. These slight differences in tracking have negligible effect on home C band and TVRO dishes since they have relatively wide-beam designs. See also Diseqc Equatorial mount References External links Explanation of satellite antenna polar mount GEOSTATIONARY ORBITS PART 4: SATELLITE ANTENNA MOUNTS Declination Angle Chart Index and Glossary of Terms Satellite broadcasting