Crthuky

A spaceship crew, during their interstellar travel loses control of the spaceship for a few hours due to external factors (exact factor not important). This causes the spaceship to deviate from it's original course. The deviation is sudden and large (imagine the spaceship spinning(?) in space during deviation).

The question is, once the crew stopped the spaceship from spinning, how are they going to re-orient it along it's original direction? What reference points can one use in space?

I think one cannot use distant stars as reference points since we only know stars by their geocentric coordinates. So, is there anyway for my space travellers to save themselves or are they doomed??

I think one cannot use distant stars as reference points since we only know stars by their geocentric coordinates.

We are smarter than that.

The Pioneer golden plaques, besides having porn, also had this:

With this you can locate the sun, by figuring out where the signals of 14 pulsars meet.

If you can track objects of interest, you can find yourself. Before GPS was invented, US military jets of the 60's to the 90's sometimes used the position of stars to locate themselves:

In flight, the ANS, which sat behind the reconnaissance systems officer's (RSO's), position, tracked stars through a circular quartz glass window on the upper fuselage. Its "blue light" source star tracker, which could see stars during both day and night, would continuously track a variety of stars as the aircraft's changing position brought them into view. The system's digital computer ephemeris contained data on a list of stars used for celestial navigation: the list first included 56 stars, and was later expanded to 61. The ANS could supply altitude and position to flight controls and other systems, including the mission data recorder, automatic navigation to preset destination points, automatic pointing and control of cameras and sensors, and optical or SLR sighting of fixed points loaded into the ANS before takeoff. According to Richard Graham, a former SR-71 pilot, the navigation system was good enough to limit drift to 1,000 ft (300 m) off the direction of travel at Mach 3.

Also remember that in space you are always orbiting something. If you can figure your altitude from the barycenter and your orbital speed, you can calculate the shape of your orbit. Find any other two objects also orbiting that barycenter and, given database entries of those objects' orbits you may not only know where you are, but also when you are.

If you've got a math geek with a knack for astronomy onboard, they may be able to calculate that with pen and paper just like old man Kepler and his pals used to. They will use the same equations that Kerbal Space Program uses to position your spacecrafts whenever you load a saved game.

I think one cannot use distant stars as reference points since we only know stars by their geocentric coordinates.

Wrong.

We also know geometry, and if know the geocentric coordinates and the present coordinates, we can determine the displacement vector between the two, which give us the desired information: where are we in space.

One or more wide field images can help in finding known stars, and from there determine the rotation with respect the last known position. Mind that, knowing the trajectory up until before the incident, the maps are quite updated.

A lot of time in science fiction, and in real life space craft use pulsars to navigate.

X-ray pulsar-based navigation and timing (XNAV) or simply pulsar navigation is a navigation technique whereby the periodic X-ray signals emitted from pulsars are used to determine the location of a vehicle, such as a spacecraft in deep space. A vehicle using XNAV would compare received X-ray signals with a database of known pulsar frequencies and locations. Similar to GPS, this comparison would allow the vehicle to triangulate its position accurately (±5 km). The advantage of using X-ray signals over radio waves is that X-ray telescopes can be made smaller and lighter. Experimental demonstrations have been reported in 2018.