Yes, the Sabbath begins at sundown on Friday and ends at sundown on Saturday.

The veneration of Sunday is yet another pagan tradition that infiltrated Christianity via the conversion of the Roman Emperor Constantine. It resulted in such a huge, sudden influx of pagans into the church that they did not assimilate. This is how Sunday, the sacred day for pagan sun worshipers, usurped the Sabbath as the church's official day of the lord.

The Adventists are right about the true Sabbath and a number of other things as well, but I do NOT believe they are right about a National Sunday Law being the mark of the beast.

I suppose in my case it wouldn't matter anyway. I've been keeping the proper Sabbath ever since I learned that Sunday is bogus and have no intention of changing that for any reason.