@mostapha I did little investigation and found that the issue is occurring because gendaylit is not getting the meridian values assigned to it.
c:\radiance\bin\gendaylit 6 21 12 -W 773.0 253.0 -o -34.8 -O 0 -a 31.25
The default value for gendaylit corresponds to San Francisco (-m 120). So as long as we do a simulation for a location within the continental United States (or locations with longitudes in the vicinity of 120 degrees Standard Meridian, the results will look okay, but still be slightly off. The error will increase for other locations. That’s why Abraham is getting a dark sky as the local time as per gendaylit is 10:30 PM
This is only an issue with HB[+] point-in-time simulations at present, which I hope people are still doing through Honeybee legacy. For all the matrix based stuff, the meridian values are added automatically through Radiance based
gendaymtx. The fix should be simple, just add the
-m flag in gendaylit either in the plus plugin or downstream in core ( I will let you handle that ! ).
This might also explain the difference in results that @MingboPeng was getting. Thank you to @AbrahamYezioro and @AndreaZani905 for pointing this out.