APSF
//- Convert galactic latitude and longitude in user fields 
//- into B1950.0 RA and Dec. Only objects with correct lat/long
//- values in the chosen user fields will be considered.
//- Note: A forthcoming update for V1.6 will allow the coordinates
//- to be converted to J2000.0.
//-
//- Paul Rodman, Dec 2007
//- 
//- Version 1.0  4 Dec 2007
//-   Initial release

// Set these up to the correct values for your application (1,2,3, or 4)
const LatitudeField = 1   // latitude in User Field 1
const LongitudeField = 2  // longitude in User Field 2

function FromLatLong(lat as double, long as double, byref ra as double, byref dec as double) as boolean
  // Convert lat/long to RA/Dec. Return TRUE if lat/long are in correct range, FALSE otherwise.
  
  dim y as double
  
  const DegreesToRadians=0.017453292
  const RadiansToDegrees=57.29577951
  const DegreesToHours=0.06666666667
  
  // Check lat/long
  if lat<-90.0 or lat>90.0 or long<0.0 or long>360.0 then return false
  
  // Convert to B1950.0 coordinates
  y = atan2(sin((long-123.0)*DegreesToRadians), _
        cos((long-123.0)*DegreesToRadians)*sin(27.4*DegreesToRadians)- _
        tan(lat*DegreesToRadians)*cos(27.4*DegreesToRadians))
  ra = y*RadiansToDegrees+12.25
  ra = ra*DegreesToHours
  if ra<0.0 then ra=ra+24.0
  
  dec = asin(sin(lat*DegreesToRadians)*sin(27.4*DegreesToRadians)+ _
          cos(lat*DegreesToRadians)*cos(27.4*DegreesToRadians)* _
          cos((long-123.0)*DegreesToRadians))*RadiansToDegrees
          
  // Convert to epoch J2000.0
  // Omitted, since this functionality isn't currently present
  return true
end function

// MAIN program

dim i as integer, lat,long,ra,dec as double, slat,slong as string

// For each object in the plan
for i=1 to nObj
  // Get the user field values
  select case LatitudeField
  case 1
    slat=Obj(i).User1
  case 2
    slat=Obj(i).User2
  case 3
    slat=Obj(i).User3
  case 4
    slat=Obj(i).User4
  end select
  
  select case LongitudeField
  case 1
    slong=Obj(i).User1
  case 2
    slong=Obj(i).User2
  case 3
    slong=Obj(i).User3
  case 4
    slong=Obj(i).User4
  end select
  
  // Check to make sure both user fields contain numeric values
  if IsNumeric(slat) and IsNumeric(slong) then
    lat=CDbl(slat)
    long=CDbl(slong)
    if FromLatLong(lat,long,ra,dec) then
      Obj(i).RA=ra
      Obj(i).Dec=dec
    end if
  end if
next