1. Go to Nasa Ephemeris
http://ssd.jpl.nasa.gov/horizons.cgi
2. Change Settings sothat it looks like as given below
Ephemeris Type [change] : OBSERVER
Target Body [change] : Venus [299]
Observer Location [change] : Geocentric [500]
Time Span [change] : Start=2013-02-01, Stop=2013-06-30, Step=1 h
Table Settings [change] : QUANTITIES=1,9,12,20,23,24
Display/Output [change] : default (formatted HTML)
Make sure you have 12 in QUANTITIES which is ang-sep/v = Target-primary angular separation and visibility. The angle between the
center of target object and the center of the primary body it revolves around, as seen by the observer. Units: ARCSECONDS
3. Generate Ephemeris and note down following rows (note NASA timings are in UTC and to compare them please change DrikPanchang.com location to London, UK and adjust for DST manually)
2013-Feb-16 15:00 21 23 06.29 -16 28 34.3 -3.88 0.83 35985.49/* 1.68079085263511...
2013-May-06 09:00 03 34 06.93 +19 02 40.6 -3.88 0.81 36008.81/* 1.69293750395463...
4. Take ang-sep/v which is angular separation between Venus and the Sun in Arcseconds
2013-Feb-16 15:00 35985.49 = 9.996° (divide ARCSECONDS by 3600 to convert into DEGREES)
2013-May-06 09:00 36008.81 = 10.002° (divide ARCSECONDS by 3600 to convert into DEGREES)
