/// <summary>
/// This function will figure out what guiding pulses to send to the mount to achieve
/// a random guide direction equivalent to a total guide pulse duration set by the user.
/// Note that total guide pulse duration sent to mount will be more than the guide
/// pulse duration set by the user, but overall distance from origin will be the same
/// as if the pulse had been fully applied to one of the N/S/W/E axes. Guide directions are
/// set to be roughly countering one another, to avoid too much deviation from target.
/// </summary>
/// <param name="duration">Rather than a time, should be considered as actual distance from origin prior to dither</param>
/// <returns>Parameters for two guide pulses, one in N/S direction and one in E/W direction</returns>
private GuidePulses SelectDitherPulse(TimeSpan duration)
{
double ditherAngle = (previousAngle + Math.PI) + random.NextDouble() * Math.PI - Math.PI / 2;
previousAngle = ditherAngle;
double cosAngle = Math.Cos(ditherAngle);
double sinAngle = Math.Sin(ditherAngle);
GuidePulses resultPulses = new GuidePulses();
if (cosAngle >= 0)
{
resultPulses.directionWestEast = GuideDirections.guideEast;
}
else
{
resultPulses.directionWestEast = GuideDirections.guideWest;
}
if (sinAngle >= 0)
{
resultPulses.directionNorthSouth = GuideDirections.guideNorth;
}
else
{
resultPulses.directionNorthSouth = GuideDirections.guideSouth;
}
resultPulses.durationWestEast = TimeSpan.FromMilliseconds((int)Math.Round(Math.Abs(duration.TotalMilliseconds * cosAngle)));
resultPulses.durationNorthSouth = TimeSpan.FromMilliseconds((int)Math.Round(Math.Abs(duration.TotalMilliseconds * sinAngle)));
return(resultPulses);
}
public async Task <bool> Dither(CancellationToken ct)
{
State = "Dithering...";
TimeSpan Duration = TimeSpan.FromSeconds(profileService.ActiveProfile.GuiderSettings.DirectGuideDuration);
TimeSpan SettleTime = TimeSpan.FromSeconds(profileService.ActiveProfile.GuiderSettings.SettleTime);
bool DitherRAOnly = profileService.ActiveProfile.GuiderSettings.DitherRAOnly;
//In theory should not be hit as guider gets disconnected when telescope disconnects
if (!telescopeInfo.Connected)
{
return(false);
}
else
{
GuidePulses PulseInstructions = SelectDitherPulse(Duration);
if (!DitherRAOnly)
{
telescopeMediator.PulseGuide(PulseInstructions.directionWestEast, (int)PulseInstructions.durationWestEast.TotalMilliseconds);
await Utility.Utility.Delay(PulseInstructions.durationWestEast, ct);
telescopeMediator.PulseGuide(PulseInstructions.directionNorthSouth, (int)PulseInstructions.durationNorthSouth.TotalMilliseconds);
await Utility.Utility.Delay(PulseInstructions.durationNorthSouth, ct);
await Utility.Utility.Delay(SettleTime, ct);
}
else
{
//Adjust Pulse Duration for RA only dithering. Otherwise RA only dithering will likely provide terrible results.
Duration = TimeSpan.FromMilliseconds((int)Math.Round(Duration.TotalMilliseconds * (0.5 + random.NextDouble())));
telescopeMediator.PulseGuide(PulseInstructions.directionWestEast, (int)Duration.TotalMilliseconds);
await Utility.Utility.Delay(Duration, ct);
await Utility.Utility.Delay(SettleTime, ct);
}
}
State = "Idle";
return(true);
}
