julian-date

How can I convert a Julian Date with Time - e.g. 2456961.090914 (CE 2014 October 30 14:10:54.6 UT) as you can test on this website: http://aa.usno.navy.mil/data/docs/JulianDate.php in C#? I tried several algorithms I found on the net, but some don't contemplate the Julian as a double , only long or even int . Some other use DateTime.ToOADate that I do not have in the System.DateTime . How can I convert the given Julian Date to a normal/regular DateTime? Thanks to Mr. Zator answer here I was able to solve my problem like so: public DateTime JulianToDateTime(double julianDate) { double unixTime

I'm writing an application in Lua that calculates the sunset/sunrise, and to do this I had to convert the Gregorian date in to Julian days initially and do all the complex maths and such from there. I've completed the hard maths, but now I need to convert the Julian date (2456495.6833865 as an example) back to a Gregorian one, complete with the time. The only code I've found that can do this only has the day, year and month, but no mention of the time (which I believe is expressed as a fraction of the day, in this case the numbers after the decimal point) Any help would be greatly appreciated

I've written a simple code that converts a regular date to Julian date. Here's the code for those who need the same conversion: public int convertToJulian(String unformattedDate) { /*Unformatted Date: ddmmyyyy*/ int resultJulian = 0; if(unformattedDate.length() > 0) { /*Days of month*/ int[] monthValues = {31,28,31,30,31,30,31,31,30,31,30,31}; String dayS, monthS, yearS; dayS = unformattedDate.substring(0,2); monthS = unformattedDate.substring(3, 5); yearS = unformattedDate.substring(6, 10); /*Convert to Integer*/ int day = Integer.valueOf(dayS); int month = Integer.valueOf(monthS); int year =

How can a Java Date be converted into a double that represents a Julian day? How can a Julian day number be converted into a Java Date ? public static double dateToJulian(Date date) { GregorianCalendar calendar = new GregorianCalendar(); calendar.setTime(date); int year; int month; float day; int a; int b; double d; double frac; frac = (calendar.get(Calendar.HOUR_OF_DAY) / 0.000024 + calendar.get(Calendar.MINUTE) / 0.001440); b = 0; year = calendar.get(Calendar.YEAR); month = calendar.get(Calendar.MONTH) + 1; DecimalFormat ceroPlaces = new DecimalFormat("0"); day = calendar.get(Calendar.DAY_OF

I am trying to convert a Julian integer back to a date. Example: integer 2456931 = 2014/09/30 // format YYYY/MM/DD Please Help - Thanks in Advance, Here is what I developed for my own need : function dateToJulianNumber(d) { // convert a Gregorian Date to a Julian number. // S.Boisseau / BubblingApp.com / 2014 var x = Math.floor((14 - d.getMonth())/12); var y = d.getFullYear() + 4800 - x; var z = d.getMonth() - 3 + 12 * x; var n = d.getDate() + Math.floor(((153 * z) + 2)/5) + (365 * y) + Math.floor(y/4) + Math.floor(y/400) - Math.floor(y/100) - 32045; return n; } // assert September 30 2014 ->

The JulianDate object in Skyfield is a handy way to quickly produce and hold a set of time values in Julian Days, and pass them to Skyfield's at() method to calculate astronomical positions in various coordinates. (see an example script ) However, I can't seem to find an add or offset method so that I can add a time offset or an iterable of offsets to a JulianDate object. I always seem to struggle with dates and times. Here is a very simple, abstracted example. I generate jd60 which is offset from an arbitrary jd0 by 60 days. As a simple check I calculate the position of the earth at the two