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TelescopeDeclinationRate Property
The declination tracking rate (arcseconds per second, default = 0.0)

Namespace: ASCOM.DriverAccess
Assembly: ASCOM.DriverAccess (in ASCOM.DriverAccess.dll) Version: (
public double DeclinationRate { get; set; }

Property Value

Type: Double


This property, together with RightAscensionRate, provides support for "offset tracking". Offset tracking is used primarily for tracking objects that move relatively slowly against the equatorial coordinate system. It also may be used by a software guiding system that controls rates instead of using the PulseGuide method.


  • The property value represents an offset from zero motion.
  • If CanSetDeclinationRate is False, this property will always return 0.
  • To discover whether this feature is supported, test the CanSetDeclinationRate property.
  • The supported range of this property is telescope specific, however, if this feature is supported, it can be expected that the range is sufficient to allow correction of guiding errors caused by moderate misalignment and periodic error.
  • If this property is non-zero when an equatorial slew is initiated, the telescope should continue to update the slew destination coordinates at the given offset rate.
  • This will allow precise slews to a fast-moving target with a slow-slewing telescope.
  • When the slew completes, the TargetRightAscension and TargetDeclination properties should reflect the final (adjusted) destination.

This is not a required feature of this specification, however it is desirable.

See Also