Before we get into the bulk of this post the stars of the asterism Big Dipper (part of Ursa Major):
- Alkaid
- Mizar
- Alioth
- Megrez
- Phecda/Phekda
- Merak
- Dubhe
Holdstock and Edwards make it abundantly clear in the last few page of Lost Realms that a celestial bear is visible in heavens of a very important star system. The characteristics of this system:
-9 planets
-2nd planet covered in clouds
-3rd planet dry and windy
-5th planet multi-colored gas world
-6th planet with massive rings
-Apparently, located in spiral galaxy there is eye shape described as "Eye of the Mother" about 1/3 the way to edge of galaxy. This sounds like a large nebula. The Eye has appeared in other Holdstock works.
If it's important to see Ursa Major, it really cannot be in the Alliance. That said, there are two zones where this should be visible:
Sol -> Alioth
Achenar -> Alioth
In case of Raxxla, it supposedly is a place that connects universes. In the case of The Dark Wheel, they were mystery seekers seeking both Raxxla and their true home. The myth is further elaborated in Alien World, that the group may have come about as part of accident involving a generation ship. I have highlighted before, the planets that can be used to decorate our cockpits do not match Sol perfectly. We are looking for something similar to Sol that apparently holds something very important.
Whatever Raxxla is, it apparently cannot be in the Alliance itself as the celestial bear would be absent. I guess this means it is in the Bubble. Even then, that is a lot of space.