From what date is the visualisation applicable?
The visualisation applies from the 20th January 2014 when the Rosetta Spacecraft exited Deep Space Hibernation and pointed towards the Earth. The steps leading to the repointing can be seen at approx 16:00 on that date in the visualisation.
Why does it go only a short period into the future?
The data used by this visualisation is based upon “actual” pointings executed or to be executed on the spacecraft. While viewing pointings in the past is never an issue, one can only view pointings a certain time period into the future that is dependent on the current weekly planning status of the mission. Every Monday and Thursday, the trajectory & pointing of the spacecraft is confirmed for the coming days. On Monday, the pointings are confirmed for the period from Wednesday until Friday night. On Thursday, the pointings are confirmed for the period from Saturday until Tuesday night. In that respect, if looking at the tool on a Wednesday, then the pointings will cover up to a time on Friday etc.
Are the stars in the background real and “correct”, or is that just a notional star field?
The stars are real, taken from the Bright Stars Catalog. Their brightness relative to the comet may not be correct. Their colors (estimated from V and B magnitudes) may be exaggerated.
Is the appearance of the comet real too, using a shape model and real-time info on the orientation?
Yes, a real shape model is used, albeit not the highest resolution available, for data proprietary reasons. This version was also published for 3D printing purposes. Orientation of comet is based upon predictions (for the future) and reconstructions from operational data products.
Is the orientation of the spacecraft based upon real information?
The orientation of spacecraft is based upon predictions (for the future) and reconstructions from operational data products. For predictions, short term changes of spacecraft attitude which are not reflected in the simulation are in principle possible but have not occurred so far. The actuation of solar panels is modelled correctly. The actuation of the High Gain Antenna is mostly correct, however, some times there are two different antenna positions which point to the same direction. The transition between such two positions is not modelled correctly. Sometimes, the antenna just jumps from one position to the other.
In which direction is the Sun in the image.
The up direction of the image is defined by the movement of the spacecraft relative to the comet. Thus, the Sun can be in any direction. The normal vector on the solar panels always points to the Sun, so this gives an indication where it is.
What is the distance of the “camera” from the spacecraft and effective focal length of the “lens” being used to generate the view?
The observer is 33 m behind the spacecraft, offset to the side by 7.5 m. The camera has a field of view of 30 deg.