UTC time and or sunset/sunrire time

Former Member over 9 years ago

Hi,

Digital stock watch provides us with utc time and sunset/rise time.
Is there any way to access that data in a watchface made in connect iq ?
The developer documentation doesn't show it or I cannot find it.
If not, could someone help me with the calculation of these times ?
Please no external site with just formulas. I would need an actual Monkey C program for that.

Kind regards,
Dirkvd001

travis.vitek over 9 years ago

https://en.wikipedia.org/wiki/Sunrise_equation

It isn't that difficult to translate.

Former Member over 9 years ago

Not what I was looking for

https://en.wikipedia.org/wiki/Sunrise_equation

It isn't that difficult to translate.

Can be. But this was not what I asked for. Even it isn't difficult, I cannot seem to get it right.
So I would like help with the real deal : Monkey C code.

Thanks

sthainzl over 9 years ago

Hello,

Here is my code to calculate sunrise and sunset. Note that this code for some reason is about 20 minutes off, I am still debugging. But maybe there is some synergy here:

function calcSRSSAngle()

    {

		var now = Time.now();

		var info = Calendar.info(now, Time.FORMAT_SHORT);

		var d = info.day;

		var m = info.month;

		var y = info.year;

		

		var lat = 0.0;

		var lon = 0.0;

		var currloc = Act.getActivityInfo().currentLocation;

		if (currloc != null)

		{ 

			lat = currloc.toDegrees()[0].toFloat();

			lon = -currloc.toDegrees()[1].toFloat();

			//System.println("Location captured.");

		}

		var lat_ = lat/180.0*Math.PI;

		var lon_ = lon/180.0*Math.PI;

		//System.println("lat = "+lat);

		//System.println("lon = "+lon);

    	

    	// Julian Date

    	var a_j = floor((14.0-m)/12.0);

    	var y_j = y+4800.0-a_j;

    	var m_j = m+12.0*a_j-3.0;

    	//System.println("a_j = "+a_j+"; y_j = "+y_j+"; m_j = "+m_j);

    	var JDN = d + floor((153.0*m_j+2)/5) + 365*y_j + floor(y_j/4) - floor(y_j/100) + floor(y_j/400) - 32045;

    	//System.println("JDN = "+JDN);

    	

    	// Current Julian day since Jan 1, 2000

    	var n = JDN - 2451545d + 0.0008;

    	//System.println("n = "+n);

    	

    	// Mean solar noon

		var Js = lon/360.0 + n;

		//System.println("Js = "+Js);

		

		// Solar mean anomaly

		var M = floatMod(357.5291 + 0.98560028*Js, 360.0);

		//System.println("M = "+M);

		var M_ = M/180.0*Math.PI;

		

		// Equation for the center

		var C = 1.9148*Math.sin(M_) + 0.02*Math.sin(2*M_) + 0.0003*Math.sin(3*M_);

		//System.println("C = "+C);

		

		// Ecliptic longitude

		var la = floatMod(M + C + 180 + 102.9372, 360);

		//System.println("la = "+la);

		var la_ = la/180*Math.PI;

		

		// Solar transit

		var corr = Js - (0.0053*Math.sin(M_) - 0.0069*Math.sin(2*la_));

		var Jtr = 2451545d + corr;

		//System.println("corr = "+corr);

		//System.println("Jtr = "+Jtr);

		

		// Declination of the sun

		var sind = Math.sin(la_) * Math.sin(23.44/180*Math.PI);

		var delta = Math.asin(sind);

		//System.println("delta = "+delta);

		

		// Hour angle

		var cosom = (Math.sin(-0.83/180*Math.PI) - Math.sin(lat_) * sind) / (Math.cos(lat_) * Math.cos(delta));

		//System.println("cosom = "+cosom);

		var om = Math.acos(cosom);

		//System.println("om = "+om);

		

		//Calculate sunrise and sunset[edit]

		var trdel = om/(2*Math.PI);

		//System.println("trdel = "+trdel);

		var Jset = Jtr + trdel;

		//System.println("Jset = "+Jset);

		var Jrise = Jtr - trdel;

		//System.println("Jrise = "+Jrise);

		

		var sunset_h = (Jset - (JDN-0.5)) * 24;

		var sunrise_h = (Jrise - (JDN-0.5)) * 24;

		var sunset_m = (sunset_h - sunset_h.toNumber()) * 60;

		var sunrise_m = (sunrise_h - sunrise_h.toNumber()) * 60;

		//System.println("sunrise = "+sunrise_h.toNumber()+":"+sunrise_m.toNumber());

		//System.println("sunset = "+sunset_h.toNumber()+":"+sunset_m.toNumber());

		

		var result = new [2];

		result[0] = sunrise_h;

		result[1] = sunset_h;

		

		return result;

    }

The bit above calls the following two functions:

function floor(x)

    {

    	if (x.abs() == x)

    	{

    		return x.toNumber();

    	}

    	else

    	{

    		var x_ = -x;

    		x_ = x_.toNumber();

    		return -x_;

    	}

    }

function floatMod(a, b)

	{

    	return (a - b * floor(a / b));

	}

Former Member over 9 years ago

Wrong times

Hi,

Thanks for your code. Something is wrong though.
If I use your calculation method, it returns different times everytime I calculate it.
And I get results like 11:51AM and 25:15 PM ???

Strange

MazzeV over 9 years ago

Have you already been able to debug the code?