I have one also not sure of the dimensions but I could check. It is a bit of a pain carrying it. I've never got to shoot at anything but targets from mine because I usually don't end up carrying it with hunting.
Depending on the size of your day pack, it might fit. However, I would just take some collapsible shooting sticks if you are planning on moving around much. It takes a bit to get it set up. Mine gets used in static situations. It's great in a ground blind! If you have an area you plan on sitting in for a few hours it could be made to work, but it'd be more trouble than I would put up with for a 'run and gun' approach.
My bil has one and it is great-as long as you don't have to carry the damn thing very far. It is better for shooting prairie dogs etc. from a more static position. I would rather take my Harris or Bog Pod for long hikes.