The Astronomical New Moon is on Thursday 11 February 2021 at 7.07pm.
The calculations for crescent visibility on Friday 12 February 2021 for London is as follows:
Crescent age 22 hours 5 minutes
Moon lag time 41 minutes
Crescent elongation 11.39 degrees
Crescent altitude 4.47 degrees
The crescent is unlikely to be seen on this day.
Saturday 13th February 2021 will therefore be 30th Jamadi ul Akhar 1442AH.
1st Rajab 1442AH will inshaAllah be on Sunday 14 February 2021 in Europe.