docs: def ec2eq(self):
          """Convert ecliptic coordinates to equatorial coordinates"""
  
          import math
          #from numpy.matlib import sin, cos, arcsin, arctan2
          from math import sin, cos
          from math import asin as arcsin
          from math import atan2 as arctan2
          from math import acos as arccos
          
          eb=self.eb
          el=self.el
          ob=math.radians(23.439281)
          
          dec = arcsin(sin(eb)*cos(ob)+cos(eb)*sin(ob)*sin(el))
          sra = (sin(dec)*cos(ob)-sin(eb))/(cos(dec)*sin(ob))
  
          cra = cos(el)*cos(eb)/cos(dec)
          if sra < 1 and sra > -1 :
              sa= arcsin(sra)
          else:
              sa = 0
          ca= arccos(cra)
          tsa=sa
          tca=ca
          if tsa<0 :
              ca=2.0*math.pi-ca
          if tca>=math.pi/2.0:
              sa=math.pi-sa
          if ca >= math.pi*2.0:
              ca=ca-math.pi*2.0
          self.tsa=sra
          self.tca=cra
          self.ra=ca
          self.dec=dec