Telescope Simulator, AltAz mount and derotation option

drivers/ccd/ccd_simulator.cpp

@@ -75,7 +75,14 @@ bool CCDSim::setupParameters()
     m_PEPeriod = SimulatorSettingsNP[SIM_PE_PERIOD].getValue();
     m_PEMax = SimulatorSettingsNP[SIM_PE_MAX].getValue();
     m_TimeFactor = SimulatorSettingsNP[SIM_TIME_FACTOR].getValue();
-    RotatorAngle = SimulatorSettingsNP[SIM_ROTATION].getValue();
+    // This is the rotation of the simulated camera respective to North.
+    // Because the simulated star field is calculated with their RA/DEC-coordinates
+    // (see DrawCcdFrame()) the origin angle of star field points north. So this value
+    // for EQ mounts normally simulate a certain camera offset and is a constant.
+    // For ALTAZ-mount this variable is altered consecutively by the value of the parallactic
+    // angle (transfered through a signal from KStars/skymapdrawabstract.cpp) and this way used
+    // to simulate the deviation of the camera orientation from N.
+    m_CameraRotation = SimulatorSettingsNP[SIM_ROTATION].getValue();
 
     uint32_t nbuf = PrimaryCCD.getXRes() * PrimaryCCD.getYRes() * PrimaryCCD.getBPP() / 8;
     PrimaryCCD.setFrameBufferSize(nbuf);
@@ -137,6 +144,9 @@ bool CCDSim::initProperties()
 
     SimulatorSettingsNP.fill(getDeviceName(), "SIMULATOR_SETTINGS",
                              "Settings", SIMULATOR_TAB, IP_RW, 60, IPS_IDLE);
+    // load() is important to fill all editfields with saved values also, so ISNewNumber() of one field
+    // doesn't update the other fields of the group with the "old" contents.
+    SimulatorSettingsNP.load();
 
     // RGB Simulation
     SimulateBayerSP[INDI_ENABLED].fill("INDI_ENABLED", "Enabled", ISS_OFF);
@@ -607,15 +617,18 @@ int CCDSim::DrawCcdFrame(INDI::CCDChip * targetChip)
             "pprx: %g pixels per radian ppry: %g pixels per radian ScaleX: %g arcsecs/pixel ScaleY: %g arcsecs/pixel",
             pprx, ppry, Scalex, Scaley);
 #endif
-
-        double theta = 270;
+        m_CameraRotation = SimulatorSettingsNP[SIM_ROTATION].getValue();
+        double theta = m_CameraRotation;
         if (!std::isnan(RotatorAngle))
             theta += RotatorAngle;
         if (pierSide == 1)
             theta -= 180;       // rotate 180 if on East
         theta = range360(theta);
+        LOGF_DEBUG("Rotator Angle: %f, Camera Rotation: %f", RotatorAngle, m_CameraRotation);
 
         // JM: 2015-03-17: Next we do a rotation assuming CW for angle theta
+        // TS: 2025-06-09: Below we have "Invert horizontally" and in the end
+        // this produces a rotation CCW with origin N (TODO: adjust matrix?)
         pa = pprx * cos(theta * M_PI / 180.0);
         pb = ppry * sin(theta * M_PI / 180.0);
 
@@ -778,7 +791,7 @@ int CCDSim::DrawCcdFrame(INDI::CCDChip * targetChip)
                         ccdx = pa * sx + pb * sy + pc;
                         ccdy = pd * sx + pe * sy + pf;
 
-                        // Invert horizontally
+                        // Invert horizontally and transform CW to CCW (see above)
                         ccdx = ccdW - ccdx;
 
                         rc = DrawImageStar(targetChip, mag, ccdx, ccdy, exposure_time);
@@ -1312,7 +1325,7 @@ bool CCDSim::ISSnoopDevice(XMLEle * root)
             if (!strcmp(name, "FOCUS_ABSOLUTE_POSITION"))
             {
                 FocuserPos = atol(pcdataXMLEle(ep));
-
+                LOGF_DEBUG("Snooped FocuserPosition %g", FocuserPos);
                 // calculate FWHM
                 double focus       = FocusSimulationNP[SIM_FOCUS_POSITION].getValue();
                 double max         = FocusSimulationNP[SIM_FOCUS_MAX].getValue();
@@ -1326,6 +1339,20 @@ bool CCDSim::ISSnoopDevice(XMLEle * root)
             }
         }
     }
+    else if (!strcmp(propName, "ABS_ROTATOR_ANGLE"))
+    {
+        for (ep = nextXMLEle(root, 1); ep != nullptr; ep = nextXMLEle(root, 0))
+        {
+            const char * name = findXMLAttValu(ep, "name");
+
+            if (!strcmp(name, "ANGLE"))
+            {
+                RotatorAngle = atof(pcdataXMLEle(ep));
+                LOGF_DEBUG("Snooped RotatorAngle %f", RotatorAngle);
+                return true;
+            }
+        }
+    }
     // We try to snoop EQPEC first, if not found, we snoop regular EQNP
 #ifdef USE_EQUATORIAL_PE
     const char * propName = findXMLAttValu(root, "name");

drivers/ccd/ccd_simulator.h

@@ -165,6 +165,7 @@ class CCDSim : public INDI::CCD, public INDI::FilterInterface
     float m_OAGOffset { 0 };
     float m_RotationCW { 0 };
     float m_TimeFactor { 1 };
+    double m_CameraRotation { 0 };
 
     bool m_SimulateBayer { false };
 

drivers/telescope/scopesim_helper.cpp

@@ -115,6 +115,11 @@ Axis::AXIS_TRACK_RATE Axis::TrackRate()
     return trackingRate;
 }
 
+double Axis::getTrackingRateDegSec()
+{
+    return TrackingRateDegSec.Degrees();
+}
+
 void Axis::StartGuide(double rate, uint32_t durationMs)
 {
     // rate is fraction of sidereal, signed to give the direction
@@ -149,7 +154,7 @@ void Axis::update()         // called about once a second to update the position
     {
         position += TrackingRateDegSec * interval;
         target += TrackingRateDegSec * interval;
-        //LOGF_EXTRA1("%s: tracking, rate %f, position %f, target %f", axisName, TrackingRateDegSec.Degrees(), position.Degrees(), target.Degrees());
+        LOGF_EXTRA1("%s: tracking, rate %f, position %f, target %f", axisName, TrackingRateDegSec.Degrees(), position.Degrees(), target.Degrees());
     }
 
     // handle the slew
@@ -230,28 +235,33 @@ Angle Alignment::lst()
 
 void Alignment::mountToApparentHaDec(Angle primary, Angle secondary, Angle * apparentHa, Angle* apparentDec)
 {
-    // Primary instrument axis: "Angle" is negative PA-system looking SCP
-    // Secondary instrument axis: "Angle" is negative PA-system looking E
+
     Angle prio, seco;
     // get instrument place
     switch (mountType)
     {
         case MOUNT_TYPE::ALTAZ:
+            // Primary instrument axis: Negative PA-system looking down from Zenith:Nadir, origin "HA-like"!!!
+            // Secondary instrument axis: Positive PA-system looking at E, origin "DEC-like"
         case MOUNT_TYPE::EQ_FORK:
+            // Primary instrument axis: ??
+            // Secondary instrument axis: ??
             seco = (latitude >= 0) ? secondary : -secondary;
             prio = primary;
             break;
         case MOUNT_TYPE::EQ_GEM:
             seco = (latitude >= 0) ? secondary : -secondary; // northern : southern hemisphere
-            if (seco > 90 || seco < -90) // pierside west/looking east (cf. apperentHaDecToMount())
+            if (seco > 90 || seco < -90) // pierside west/looking east (cf. apparentHaDecToMount())
             {
-                prio = primary + Angle(180.0);  // Ha is negative PA-system looking SCP
-                seco = Angle(180.0) - seco;     // Dec is positive PA-system looking E
+                // Primary instrument axis: Negative PA-system looking down from NCP:SCP, origin opposite HA-like
+                // Secondary instrument axis: Negative PA-system looking at E, origin opposite DEC-like
+                prio = primary + Angle(180.0); // Primary to Ha transformation to get negative PA-system with origin HA-like
+                seco = Angle(180.0) - seco;    // Secondary to Dec transformation to get positive PA-system origin DEC-like
             }
             else
             {
-                prio = primary;
-                seco = secondary;
+                prio = primary;    // Primary already rotated by 180, so no transformation to get origin HA-like
+                seco = secondary;  // Secondary already rotated by 180, so no transformation to get origin DEC-like
             }
             break;
     }
@@ -262,13 +272,15 @@ void Alignment::mountToApparentHaDec(Angle primary, Angle secondary, Angle * app
     {
         Angle rot = latitude - Angle(90);
         Vector haDec = Vector(prio, seco).rotateY(rot);
-        *apparentHa = haDec.primary();
-        *apparentDec = haDec.secondary();
-        LOGF_EXTRA1("m2a Azm Alt %f, %f  Ha Dec %f, %f  rot %f", prio.Degrees(), seco.Degrees(), apparentHa->Degrees(),
+        // Primary instrument axis: Negative PA-system looking down from Zenith:Nadir, origin "HA-like" ...
+        *apparentHa = haDec.primary(); // ... so there is no transformation needed!
+        // Secondary instrument axis: Positive PA-system looking east, origin "DEC-like" ...
+        *apparentDec = haDec.secondary(); // ... so there is no transformation needed!
+        LOGF_EXTRA1("ALTAZ to apparent HaDec: pri %f, sec %f to ha %f, dec %f  rot %f", prio.Degrees(), seco.Degrees(), apparentHa->Degrees(),
                     apparentDec->Degrees(), rot.Degrees());
     }
     else
-        LOGF_EXTRA1("mountToApparentHaDec: pri %f, sec %f to ha %f, dec %f", prio.Degrees(), seco.Degrees(), apparentHa->Degrees(),
+        LOGF_EXTRA1("EQ to apparent HaDec: pri %f, sec %f to ha %f, dec %f", prio.Degrees(), seco.Degrees(), apparentHa->Degrees(),
                     apparentDec->Degrees());
 }
 
@@ -277,7 +289,7 @@ void Alignment::mountToApparentRaDec(Angle primary, Angle secondary, Angle * app
     Angle ha;
     mountToApparentHaDec(primary, secondary, &ha, apparentDec);
     *apparentRa = lst() - ha;
-    LOGF_EXTRA1("mountToApparentRaDec: pri %f, sec %f to ha %f, ra %f, dec %f", primary.Degrees(), secondary.Degrees(), ha.Degrees(),
+    LOGF_EXTRA1("mount to apparent RaDec: pri %f, sec %f to ha %f, ra %f, dec %f", primary.Degrees(), secondary.Degrees(), ha.Degrees(),
                 apparentRa->Degrees(), apparentDec->Degrees());
 }
 
@@ -291,12 +303,14 @@ void Alignment::apparentHaDecToMount(Angle apparentHa, Angle apparentDec, Angle*
         Vector altAzm = Vector(apparentHa, apparentDec).rotateY(Angle(90) - latitude);
         // for now we are making no mount corrections
         // this all leaves me wondering if the GEM corrections should be done before the mount model
-        *primary = altAzm.primary();
-        *secondary = altAzm.secondary();
-        LOGF_EXTRA1("a2M haDec %f, %f Azm Alt %f, %f", apparentHa.Degrees(), apparentDec.Degrees(), primary->Degrees(),
+        // Ha axis: Negative PA-system looking down from Zenith:Nadir, origin "HA-like" ...
+        *primary = altAzm.primary(); // ... so there is no tranformation needed!
+        // Dec axis: Positive PA-system looking at east, origin "DEC-like" ...
+        *secondary = altAzm.secondary(); // ... so there is no tranformation needed!
+        LOGF_EXTRA1("apparent HaDec to ALTAZ: ha %f, dec %f  to pri %f, sec %f", apparentHa.Degrees(), apparentDec.Degrees(), primary->Degrees(),
                     secondary->Degrees() );
     }
-    // Ha is negative PA-system looking SCP
+    // Ha is negative PA-system looking down to NCP:SCP
     // Dec is positive PA-system looking E
     Angle instrumentHa, instrumentDec;
     // ignore diurnal aberrations and refractions to get observed ha, dec
@@ -306,36 +320,42 @@ void Alignment::apparentHaDecToMount(Angle apparentHa, Angle apparentDec, Angle*
     switch (mountType)
     {
         case MOUNT_TYPE::ALTAZ:
+            // Ha axis: Negative PA-system looking down to Zenith:Nadir pole, origin "HA-like"
+            // Dec axis: Positive PA-system looking at east, origin "DEC-like"
             break;
         case MOUNT_TYPE::EQ_FORK:
+            // Primary instrument axis: ??
+            // Secondary instrument axis: ??
             *primary = instrumentHa;
             *secondary = (latitude >= 0) ? instrumentDec : -instrumentDec;  // northern : southern hemisphere
             break;
         case MOUNT_TYPE::EQ_GEM:
             if (instrumentHa < flipHourAngle)  // pierside west (looking east)
             {
-                *primary = instrumentHa + Angle(180);    // Primary instrument axis: "Angle" is negative PA-system looking SCP
-                *secondary = Angle(180) - instrumentDec; // Secondary instrument axis: "Angle" is negative PA-system looking E
+                // Ha axis: Negative PA-system looking down from NCP:SCP, origin HA-like
+                // Dec axis: Positive PA-system looking at E, origin DEC-like
+                *primary = instrumentHa + Angle(180);    // Ha to Primary to get negative PA-system with origin opposite HA-like
+                *secondary = Angle(180) - instrumentDec; // Dec to Secondary to get positive PA-system with origin DEC-like
             }
             else
             {
-                *primary = instrumentHa;
-                *secondary = instrumentDec;
+                *primary = instrumentHa;    // Ha already rotated by 180, so no transformation to get origin opposite HA-like
+                *secondary = instrumentDec; // Dec already rotated by 180, so no transformation to get origin opposite DEC-like
             }
             if (latitude < 0)  // southern hemisphere
                 *secondary = -*secondary;
             break;
     }
     if (mountType != MOUNT_TYPE::ALTAZ)
-        LOGF_EXTRA1("apparentHaDecToMount: ha %f, dec %f to pri %f, sec %f", apparentHa.Degrees(), apparentDec.Degrees(), primary->Degrees(),
+        LOGF_EXTRA1("apparent HaDec to EQ: ha %f, dec %f to pri %f, sec %f", apparentHa.Degrees(), apparentDec.Degrees(), primary->Degrees(),
                     secondary->Degrees() );
 }
 
 void Alignment::apparentRaDecToMount(Angle apparentRa, Angle apparentDec, Angle* primary, Angle* secondary)
 {
     Angle ha = lst() - apparentRa;
     apparentHaDecToMount(ha, apparentDec, primary, secondary);
-    LOGF_EXTRA1("apparentRaDecToMount: ra %f, ha %f, dec %f to pri %f, sec %f", apparentRa.Degrees(), ha.Degrees(), apparentDec.Degrees(),
+    LOGF_EXTRA1("apparent RaDec to mount: ra %f, ha %f, dec %f to pri %f, sec %f", apparentRa.Degrees(), ha.Degrees(), apparentDec.Degrees(),
                 primary->Degrees(), secondary->Degrees());
 }
 

drivers/telescope/scopesim_helper.h

@@ -31,6 +31,8 @@
  *
  */
 
+/// The transformations are based on the paper "Matrix Method for Coordinates Transformation" written by Toshimi Taki
+
 #pragma once
 
 #include <stdint.h>
@@ -256,7 +258,10 @@ class Angle
 /// Implements a generic Axis which can be used for equatorial or AltAz mounts for both axes.
 ///
 /// For an equatorial mount use the TrackRate to set the standard tracking rates. for the primary axis only.
+/// (TS 5.25: Axis entails the angles of the rotation around the mechanical axes of the mount.)
 /// For an AltAz mount the TrackingRateDegSec rate must be set for both axes.
+/// (TS 5.25: The tracking rates of the mechanical axes vary with the positions.
+/// See "Deriving Field Rotation Rate for an Alt-Az Mounted Telescope" by Russell P. Patera1)
 ///
 class Axis
 {
@@ -277,7 +282,7 @@ class Axis
         void setDegrees(double degrees);
         void setHours(double hours);
 
-        Angle position;         // current axis position
+        Angle position; // current angle of the telescope position about axis
 
         void StartSlew(Angle angle);
 
@@ -311,6 +316,8 @@ class Axis
         ///
         AXIS_TRACK_RATE TrackRate();
 
+        double getTrackingRateDegSec();
+
         ///
         /// \brief TrackingRateDegSec
         ///