Well, the Hijri date 15 Muharram 1511 corresponds to the Gregorian date Thursday, 14 August 2087. This date lies in the first month of the Hijri year 1511 AH, which is Muharram of 1511 AH. Both this Hijri and Gregorian date occur on the single day that is Thursday without any doubt. The Arabic date 1511/01/15 is calculated using the Umm Al-Qura calendar and the sighting of the moon. One thing to remember is that this Arabic date may occur on different Gregorian date depending upon the region and country and obviously the moon.
If you are still not sure about the date then you can use our Arabic date converter.
The following is the conversion of the Gregorian date 14 August 2087 to its equivalent Arabic date.
The following is the conversion of the Arabic date 15 Muharram 1511 AH to its equivalent Gregorian date.
يَسْـَٔلُونَكَ عَنِ ٱلسَّاعَةِ أَيَّانَ مُرْسَىٰهَا ۖ قُلْ إِنَّمَا عِلْمُهَا عِندَ رَبِّى ۖ لَا يُجَلِّيهَا لِوَقْتِهَآ إِلَّا هُوَ ۚ ثَقُلَتْ فِى ٱلسَّمَٰوَٰتِ وَٱلْأَرْضِ ۚ لَا تَأْتِيكُمْ إِلَّا بَغْتَةًۭ ۗ يَسْـَٔلُونَكَ كَأَنَّكَ حَفِىٌّ عَنْهَا ۖ قُلْ إِنَّمَا عِلْمُهَا عِندَ ٱللَّهِ وَلَٰكِنَّ أَكْثَرَ ٱلنَّاسِ لَا يَعْلَمُونَ
They ask thee of the (destined) Hour, when will it come to port. Say: Knowledge thereof is with my Lord only. He alone will manifest it at its proper time. It is heavy in the heavens and the earth. It cometh not to you save unawares. They question thee as if thou couldst be well informed thereof. Say: Knowledge thereof is with Allah only, but most of mankind know not.
Surah Al-A'raaf(7:187)