Midday 12:00 versus solar noon

Hello,
We’re using ladybug’s Sunpath 1.6.0 to create a 2 hours cumulated shadow study and after some starting difficulties it works great. We’re using a location file for Vienna Schwecht (Airport - approx. 20km away from city center, 48,12° 16,57°).

Geometrical instructions for constructing manually this shadow study point out a 6.3° (21.03 Vienna/Austria → 1. District 48,20° 16,37°) deviation for the 12 o’clock midday shadow. As I understand this “deviation” comes from the difference between midday 12:00 and solar noon which varies according to longitude and latitude and date.

This solar calculation website (https://rechneronline.de/sehwinkel/schattenlaenge.php confirms approximately this deviation → 6.12°.

The option “solar time” slightly changes the oriention of shadows but far from the given 6.3° by the construction instruction.

We would be thankful for any hints to this topic.
Regards Jakob

PS: Sorry for the very dry post but new user may just post 1 image : - (

Hello,
Someone has got an Idea where this deviation comes from? Does the sunpath module influence this? Or is it in relationship with the provided “AUT_Vienna.Schwechat.110360_IWEC.epw” EPW file?
Any hints would be welcome
Regards Jakob