Ok but I would disagree with you on a couple of things here. First, that Pagan roots of Christianity is necessarily forbidden by the Bible. I don't mean idol worship of course but rather the incorporation of nature and rituals that Pagans enjoy that many argue were the basis of some of your faith. Examples abound but just a couple are the birthday of Jesus, Easter, and a few others as well. Second, there's a Unity church right down the street from me who do use sun worship. Unity is a group out of Missouri, IIRC, and while they claim an interfaith approach, they are also very Christian in their ideals.
Well the bible considers men to be in one of two groups.
1. Those that are born again, are in the spiritual Church of Christ (I do not mean they go to any specific type of denomination, I mean they are part of the body of Christ and belong to his spiritual church), and belong to God.
2. Anyone who has not been born again is in the unbeliever camp. However unlike Islam these unbelievers are not meant to be subdued, over taxed, forced to become a believer, or killed. Our instructions are to forgive and council this second group if they wish to be counseled. The bible is packed full of warnings against the first group backsliding into the practices on the second group. In fact that is the major theme and source of trouble throughout the OT. Israel kept intermarrying into unbelieving tribes, or admiring their ways, or for a number of reasons abandoning the practices God had laid down for practices of their neighbors. I cringe when I read the wrath God sent down among them for doing this.
The reason for this is very simple. God chose Israel (because of Abrahams faith, and Israel being Abraham's children) to be his conduit for his revelation and his greatest revelation Christ was to come from their culture. They were held to higher standards and were to be unique among the nations so that the revelations sent through them would have more impact and be more profound. If you read any significant portion of the OT it will contain Israel adopting the habits of other nations and cultures, God's punishment, and Israel's restoration. He must have known what he was up to because a three year ministry of a man born in a backwater of the Roman empire has changed the world more than any other single influence.
The church down your street is also violating emphatic biblical commands. The bible prophecies that the 'church" will always get it wrong just as man does (look at what Catholicism has done over the years with it's inquisitions, witch hunts, and crusades). However God foretells of a great falling away of the church towards the end of day which I believe we are living. The end may be tomorrow or a few hundred years from now but I believe the great fall of the church has begun.
BTW: the Bible not what any Church does is the final arbiter of a theological matters.
Also I have a challenge for you. Find me a single instance where Christ, the apostles, and early church father, or any creed from a major denomination worshipped the sun or instructs us to do so. I have provided several from the bible that forbid it, lets see if you can counter them in the context.