Others like myself, use the new moon and use it as a sign. New Moon day is always the following day (as that is what a sign is for, to announce something coming, not to tell you something just happened wink emoticon ).
When it comes to signs, I like to think of it as driving down the road. When driving I see signs along the side of the road. The signs tell me of things approaching. For example a school zone may be coming up, or perhaps the speed limit is about to change, or perhaps it is a give way sign telling me to look out for oncoming traffic. A sign is always something you see, and then the event occurs.
When we read in Genesis 1:14 it says
14 Then Elohim said, “Let there be light-bearers (sun, moon, stars) in the expanse of the heavens to separate the day from the night, and let them be useful for SIGNS, and for marking seasons, days, and years;
So in order for it to be a sign, it must be seen. Think of His rainbow. It is seen. He put in in the sky to remind us of what would never occur again. He said He would never again kill all mankind with a flood, and He has kept His word going forward.
So it all depends upon the method you use.
Using the image attached, I can see the UK would have seen the moon upon January 11, which was Monday upon the Gregorian calendar. It is the same as Australia. This was when the sign was given, in the afternoon of Monday the 11th just after sunset.
If you lived in parts of Africa for example, the sign was given a Gregorian day before – On Sunday the 10th.
So if the sign was given in the UK on the Gregorian Monday the 11th in the evening, and YHWH gives us signs to warn us of events about to take place, then New Moon day started for You and I in the morning upon the Gregorian day of Tuesday the 12th.
You may have never considered this, but are you aware that we never actually see the fourth Sabbath in the scripture? Did you notice that YHWH never mentions it, even though we know it exists? Did you know that there is light shone upon New Moon day, the day right after this Sabbath? Did you know that there is light also shone upon the first Sabbath and that there is an enormous amount of light sone upon His second Sabbath? Did you also know that the third Sabbath also has light upon it? We see each of these events for if His scriptures are His Light, He shines His light upon these events. There is no light upon the fourth Sabbath, hence why if you have light from the moon, upon your fourth Sabbath, something is not lining up with what He taught us.
And therein is what so many people do not see. If you line up His calendar this way, You are shining His light upon the whole calendar and in that sense the Fourth Sabbath has light upon it. Not direct light, for the light is hidden, and many will not see it.
“The people who walked in darkness,
Have seen a great light;
Those who dwelt in the land of the shadow if death,
Upon them light has shined.”
17 For YHWH did not send His Son into the world to condemn the world, but that the world through Him might be saved.
18 “He who believes in Him is not condemned; but he who does not believe is condemned already, because he has not believed in the name of the only begotten Son of YHWH. 19 And this is the condemnation, that the light has come into the world, and men loved darkness rather than light, because their deeds were evil. 20 For everyone practicing evil hates the light and does not come to the light, lest his deeds should be exposed. 21 But he who does the truth comes to the light, that his deeds may be clearly seen, that they have been done in YHWH.”