6" PVC Pipe For Telescope Tube?

Not sure why you mention 6" PVC Pipe Diameter for UK bulders on your Makezine page but only have 5" Spider STL Files in your dropbox repository?

<a rel="nofollow" class="external free" href="https://makezine.com/projects/gaze-across-the-solar-system-with-a-3d-printed-raspberry-pi-telescope/">https://makezine.com/projects/gaze-across-the-solar-system-with-a-3d-printed-raspberry-pi-telescope/</a> I have spent hours visiting every site that references the Pikon project and most don't even mention the required tube diameter. I can get 6" pipe easily in Australia but not 5". Is it a typo?