By 2.5x do you mean the crop factor of the sensor?
I shot my picture on a 1.6x crop sensor and it turned out ok, but not ideal. I still think it's possible with all in one cameras if you have a manual exposure mode and can choose "bulb" exposure or can at least select a 20 second exposure time. The stars might be faint but then you can use stacking software to bring them out more.
The sensor in my bridge camera is the smallest on the market for conventional cameras. This camera does NOT have a bulb setting (major disappointment), and the Manual setting doesn't even allow me full access to its range of exposures/shutter speeds. It's SO "smart" that it thinks it knows better than the operator. Grrr..... If I didn't know anything about photography, I'd truly love it.....
Yeah it's too bad a lot of the nicer bridge cameras force you to give up too much control over exposure. I had used a Canon SX40HS for years and it has a great zoom range (40x) and while it doesn't have a bulb setting, it does allow you to use manual exposure, but it's not convenient to do so. I have a newer Nikon P900 with a huge zoom range (still a tiny sensor though) and it has a much better full manual mode. It's not great for everything but it is a heck of a nice option for wildlife photos in decent light because of the zoom. And it's got a built in "time lapse" movie mode for pictures of clouds racing by or cars buzzing along. It also has an intervalometer feature you can use to make your own time lapse movies. I can't upload it because it's too large but I have a time lapse of my wife's tarantula molting and that's really a neat thing to see.
But most of my recent pictures have been taken with a 6 year old Canon T3i. It's a consumer grade APS-C sensor (1,6x crop factor) DSLR. It doesn't have WiFi or bluetooth or touch screen but it has decent 18mp resolution and I used it to teach myself to use manual exposure. And I've also been shooting RAW files as well because it allows so much more latitude in processing the pictures. I am still not and probably never will be as good as a professional but my pictures have definitely shown some improvement.