APSF
//- Compute field rotation and maximum exposure time for alt/az mounts
//- Paul Rodman July-Nov, 2007
//- 
//- This script computes the rotation rate of the FOV for each user object.
//- From the camera sensor pixel dimensions, the pixel motion at the
//- corners of the sensor is computed, and from a given blur size (in pixels)
//- the maximum exposure time can be computed and placed in a user field.
//- 
//- V1.0  2007/07/31
//-       Original release.
//- V1.1  2007/09/23
//-       Avoid problems if no site is specified.
//- V1.2  2007/11/08
//-       Display "None" if rotation rate is extrememly small or zero.

sub UserField(n as integer, fnumber as integer, assigns s as string)
// Stash string in specified user field 
// (a good reason to add indexed user field to the next version of the application...)
  select case fnumber+1
  case 1
    Obj(n).User1=s
  case 2
    Obj(n).User2=s
  case 3
    Obj(n).User3=s
  case 4
    Obj(n).User4=s
  end select
end sub

dim i,PixelsX,PixelsY as integer
dim Latitude,Altitude,Azimuth,Rotation,PixelAngle as double
dim MaxBlur as double
dim computeRotationRate,computePixelRate, computeMaxTime as boolean
dim fieldRotationRate, fieldPixelRate, fieldMaxTime as integer
dim flds(-1),s as string

const DegreesToRadians = 0.01745329252
const RadiansToDegrees = 57.295779513

if currentSite=nil then 
  print "Plan must specify a a Current Site"
  return
end if

flds.Append "User Field 1"
flds.Append "User Field 2"
flds.Append "User Field 3"
flds.Append "User Field 4"

// Restore parameters from last run
PixelsX = RestoreIntegerValue("PixelsX",692) // # Pixels on long side of sensor
PixelsY = RestoreIntegerValue("PixelsY",504) // # Pixels on short side of sensor
MaxBlur = RestoreDoubleValue("MaxBlur",1)       // Maximum blur size in pixels

computeRotationRate = RestoreBooleanValue("computeRotationRate",true)
fieldRotationRate = RestoreIntegerValue("fieldRotationRate",0)
computePixelRate = RestoreBooleanValue("computePixelRate",true)
fieldPixelRate = RestoreIntegerValue("fieldPixelRate",1)
computeMaxTime = RestoreBooleanValue("computeMaxTime",true)
fieldMaxTime = RestoreIntegerValue("fieldMaxTime",2)

// Setuip dialog to change parameters
SetIntegerParameter("Sensor pixels (long edge)",PixelsX,1,4096)
SetIntegerParameter("Sensor pixels (short edge)",PixelsY,1,4096)
SetDoubleParameter("Max. blur size (pixels)",MaxBlur)

SetBooleanParameter("Compute Field Rotation (arcsec/sec)",computeRotationRate)
SetPopupParameter("Field Rotation output",fieldRotationRate,flds)
ParameterDependency("Field Rotation output","Compute Field Rotation (arcsec/sec)")

SetBooleanParameter("Compute Pixel Rotation (pixel/sec)",computePixelRate)
SetPopupParameter("Pixel Rotation output",fieldPixelRate,flds)
ParameterDependency("Pixel Rotation output","Compute Pixel Rotation (pixel/sec)")

SetBooleanParameter("Compute Max. Exposure (sec)",computeMaxTime)
SetPopupParameter("Max. Exposure output",fieldMaxTime,flds)
ParameterDependency("Max. Exposure output","Compute Max. Exposure (sec)")

if not EditParameters("Compute Field Rotation") then return

PixelsX=GetIntegerParameter("Sensor pixels (long edge)")
PixelsY=GetIntegerParameter("Sensor pixels (short edge)")
MaxBlur=GetDoubleParameter("Max. blur size (pixels)")

computeRotationRate=GetBooleanParameter("Compute Field Rotation (arcsec/sec)")
fieldRotationRate=GetPopupParameter("Field Rotation output")

computePixelRate=GetBooleanParameter("Compute Pixel Rotation (pixel/sec)")
fieldPixelRate=GetPopupParameter("Pixel Rotation output")

computeMaxTime=GetBooleanParameter("Compute Max. Exposure (sec)")
fieldMaxTime=GetPopupParameter("Max. Exposure output")

// Save parameters for next run
SaveIntegerValue("PixelsX",PixelsX)
SaveIntegerValue("PixelsY",PixelsY) 
SaveDoubleValue("MaxBlur",MaxBlur)

SaveBooleanValue("computeRotationRate",computeRotationRate)
SaveIntegerValue("fieldRotationRate",fieldRotationRate)
SaveBooleanValue("computePixelRate",computePixelRate)
SaveIntegerValue("fieldPixelRate",fieldPixelRate)
SaveBooleanValue("computeMaxTime",computeMaxTime)
SaveIntegerValue("fieldMaxTime",fieldMaxTime)

Latitude = CurrentSite.Latitude*DegreesToRadians

// Calculate angular size of outer pixels in "
PixelAngle = atan(1.414/(0.5*sqrt(PixelsX*PixelsX+PixelsY*PixelsY)))*RadiansToDegrees*3600.0

// Set user field column headings
if computeRotationRate then UserColumnNumeric(fieldRotationRate+1,"Rotation (arcsec/sec)",2)
if computePixelRate then UserColumnNumeric(fieldPixelRate+1,"Rotation (pixel/sec)",3)
if computeMaxTime then UserColumnNumeric(fieldMaxTime+1,"Max Exposure (sec)",1)

// For each object
for i=1 to nObjects
  Altitude=Obj(i).Altitude*DegreesToRadians
  if Altitude<90.0 then
    Azimuth=Obj(i).Azimuth*DegreesToRadians
    
    // Compute rotation rate in "/sec
    Rotation = 15.0 * cos(Latitude) * cos(Azimuth) / cos(Altitude)
    
    // Stash results in user fields
    if computeRotationRate then
      if abs(Rotation)<0.005 then
        UserField(i,fieldRotationRate)="None"
      else
        UserField(i,fieldRotationRate)=format(Rotation,"-0.00")
      end if
    end if
    if computePixelRate then
      if abs(Rotation)<0.005 then
        UserField(i,fieldPixelRate)="None"
      else
        UserField(i,fieldPixelRate)=format(abs(Rotation)/(PixelAngle),"-0.000")
      end if
    end if
    if computeMaxTime then
      if abs(Rotation)<0.005 then
        UserField(i,fieldMaxTime)="n/a"
      else
        UserField(i,fieldMaxTime)=format(MaxBlur/(abs(Rotation)/(PixelAngle)),"-0.0")
      end if
    end if
  end if
next