The SkyWatcher Newton Explorer-130PDS comes with the AZ4 mount in the zenith...

Product Description
The SkyWatcher Newton Explorer-130PDS reaches the zenith with the AZ4 mount...

You just have to be careful not to bump into the tripod legs and "land" between your legs.

With the Explorer-150P(DS), you can no longer reach the zenith because the tube diameter is too large.

http://www.teleskop-spezialisten.de/shop/Newton/bis-150mm/Skywatcher-Explorer-130PDS-130mm-650mm-5-1-f-5-Photo-Newton::614.html

http://www.teleskop-spezialisten.de/shop/Montierungen/Azimutale-Montierung-ALT/AZ/AZ4-Skywatcher-AZ4-Azimutale-Montierung-mit-Alu-Stativ::408.html