Tools

Maximum Altitude of Object

What This Calculator Tells You

The maximum altitude is the highest point an object reaches in your sky as Earth rotates. This occurs when the object crosses your local meridian (due south in the northern hemisphere). Knowing the maximum altitude helps you determine how good your viewing conditions will be for this object from your location.

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Sample Objects by Declination

ObjectDeclinationMax Alt at 0.0°N
Polaris+89.3°0.7°
Andromeda Galaxy (M31)+41.3°48.7°
Orion Nebula (M42)-5.4°84.6°
Omega Centauri-47.5°42.5°
Large Magellanic Cloud-69.8°20.2°

Click a row to load its declination into the calculator.

Rules of Thumb

  • Objects with Dec = your latitude pass through zenith: They reach 90° altitude
  • Objects never rise if Dec < (latitude - 90): For a 40°N observer, objects below -50° declination never rise
  • Objects are circumpolar if Dec > (90 - latitude): For a 40°N observer, objects above +50° declination never set
  • Southern observers have opposite rules: Flip the signs for southern latitudes

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