When a projector is not centered directly in front of the screen but tilted or angled towards it, the projected image will be distorted in a trapezoidal shape. However, keystone correction will correct this so the picture will be rectangular.

Nebula projectors running Android system (like Mars II, Mars II Pro, Capsule, Capsule Max, Apollo or Astro) support Auto Vertical ±40° and Manual Horizontal ±40° keystone correction (Note: Nebula Apollo only supports Auto Vertical ±40° and Manual Horizontal ±10° keystone correction). When you set auto keystone correction to "on", it can only do vertical keystone correction. For horizontal keystone correction, you need to turn off auto keystone correction by selecting Settings > Projector > Auto Keystone Correction and then manually adjust vertical, horizontal, and quadrilateral keystone correction.

If keystone correction doesn't make the projected image rectangular, please also adjust the position of your Nebula to a proper angle to avoid a distorted projection.

If you have additional questions, please contact us for further assistance.