## Looking for help converting from equatorial to horizontal coordinates

Hello Everyone,

I am seeking some help in understanding how to convert from equatorial to horizontal coordinates. I am trying to learn how to do this in excel and understand the hows and whys behind the formulas.
I will detail what I am doing and I hope those of the community with direct experience will be able to correct any mistakes that I have made.
I am using the Constellation Sculptor with a;
RA: 00 26 28
Dec: -32 5 30
Observing point is;
Latitude: 50 54 36 N
Longitude: 6 1 43 E
Date: March 27th, 2006
Time: Midnight

From what I understand this is a 6 step process;
1). Convert Hours/Degrees to Decimal Degrees
2). Convert Date to JDate
3). Get Local Sidereal Time
4). Get Hour Angle
5). Do Trig functions for Alt
6). Do Trig Functions for Az

Step 1: Convert Hours/Degrees to Decimal Degrees
For the RA I take the min dot seconds, divide that by 60 then add it to the hours and then times it by 15
26.28 / 60 = .438 + 0 = .438 * 15 = 6.57
In excel it looks like this;
=(0 + (26.28/60) * 15
For Declination, Longitude and Latitude we use the same formula except with do not multiply the value by 15.
For Dec, 5.30 / 60 = 0.088333 + -32 = -32.088333
For Lat, 54.36 / 60 = .906 + 50 = 50.906
For Long, 1.43 / 60 = .023833 + 6 = 6.023833

Step 2: Convert Date to JDate
I am pretty sure one of my mistakes is the way I am calculating the JDate. I am using these 2 tables
1 0
2 31
3 59
4 90
5 120
6 151
7 181
8 212
9 243
10 273
11 304
12 334

2000 -1.5
2001 364.5
2002 729.5
2003 1094.5
2004 1459.5
2005 1825.5
2006 2190.5
2007 2555.5
2008 2920.5
2009 3286.5
2010 3651.5
2011 4016.5
2012 4381.5
2013 4747.5
2014 5112.5
2015 5477.5

Since my date is March 27th, 2006, I add the year and month from the tables + the day
2190.5 + 59 + 27 = 2276.5
Maybe someone can point me to the correct tables or post an excel formula to calc the correct JDate.

Step 3: Get the Local Sidereal Time
I take my JDate *0.985647 + 15 * time + Decimal Degree of the Latitude + 100.46 and then mod the answer into 360
(2276.5 * 0.985647) = 2243.8253955
(15 * 0) = 0
2243.8253955 + 0 + 6.023833 + 100.46 = 2350.3092285
Mod(2350.3092285,360) = 190.309228498

Step 4: Get the Hour Angle
If the LSA  RA Decimal Degrees is less than 0 then add 360 else just do LSA  RA Decimal Degrees
190.309228498  6.57 = 183.739228498

Step 5: Do trig Functions for Alt
Alt = Sin(ALT) = Sin(DEC) * Sin(LAT) + Cos(DEC) *Cos(LAT) * Cos(HA)
Sin(DEC) * Sin(LAT) = -.53123 * .776112 = -.41229397776
Cos(DEC) * Cos(LAT) * Cos(HA) = .84723 * .630595 * -.99787 = -.53312103017
.4122939776 + -.53312103017 = -.94541
Now Sin it like this sin(-.94541) = -.81074
ALT = Degrees(ASIN(-.81074)) = -54.1681

Step 6: Do the trig functions for Az
Cos(A) = (Sin(DEC )  Sin(ALT) * Sin(LAT)) / Cos(ALT) * Cos(LAT)
Sin(DEC) = .53123
Sin(ALT) = -.81074)
Sin(LAT) = .776112