Siege duration

Hi
I'm looking for change the time duration of certain siege.
The only config i've found was:
<siegeTime>0 0 17 ? * WED</siegeTime>

17 for start hour
WED for wednesday

but what means the "0 0"
before the start hour?
or the "?"
or the "*"

is there possibilities to make the duration of the siege 2 hours for divine for exemple.

looking for informations , thx

data\static_data\siege\siege_locations.xml
https://s.micp.ru/16144.png

0 0 - second and min
* Every Wed
For duration 2 hours to change in siege_template.xml tag siege_duration to 7200 value is in seconds

version 2.7

thx
the template is

<siege_location id="1231" type="FORTRESS" world="400010000" name_id="801833">
<artifact_activation itemid="188020000" count="1" skill="12076" cd="3600"/>

modify the artifact cd ?