02-29-2020, 04:33 PM
Chas - UKIRT has two modes of observing - wide-field and Cassegrain. Wide-field means we use only one instrument, WFCAM, which sits on top of the primary mirror. This blocks the light path to the Cassegrain instruments so we can't use them in this mode. Also, the secondary mirror is different so that would have to be changed as well.
To change between modes takes about four to five days as WFCAM has to be removed from the telescope and the secondary mirror replaced, then we have to calibrate the instruments. This involves expensive heavy engineering for three days and then a couple of nights calibrating the instruments. So we plan these changes well ahead of time when we know there is a demand for Cassegrain time. It's not something we can arrange to do at short notice.
As for "bumping people off", yes we do that regularly, although we don't actually tell observers to leave because we don't normally have observers here. We carry out their programs ourselves and observe them when conditions and their scientific priorities allow, i.e., we give a preference to the higher priority projects if the weather conditions allow them to be observed. We have a few projects that are already set up to observe transient sources, i.e., gravitational wave events, gamma ray bursts, supernovae, comets and asteroids etc. If they get triggered then we "override the queue" and immediately observe those targets ahead of anything else. However, in general, the projects that are overridden tend not to lose any time, we'll either observe them later that night or in the next few nights.
The system works very well. We end up being able to observe things that occur out of the blue while also making sure we get the best science projects completed.
Lisa - I doubt we'll get a close-up view, the thing is about the size of a car, so is very small. I do think we'll figure out what it is though, either the body of an old rocket or an actual asteroid.
To change between modes takes about four to five days as WFCAM has to be removed from the telescope and the secondary mirror replaced, then we have to calibrate the instruments. This involves expensive heavy engineering for three days and then a couple of nights calibrating the instruments. So we plan these changes well ahead of time when we know there is a demand for Cassegrain time. It's not something we can arrange to do at short notice.
As for "bumping people off", yes we do that regularly, although we don't actually tell observers to leave because we don't normally have observers here. We carry out their programs ourselves and observe them when conditions and their scientific priorities allow, i.e., we give a preference to the higher priority projects if the weather conditions allow them to be observed. We have a few projects that are already set up to observe transient sources, i.e., gravitational wave events, gamma ray bursts, supernovae, comets and asteroids etc. If they get triggered then we "override the queue" and immediately observe those targets ahead of anything else. However, in general, the projects that are overridden tend not to lose any time, we'll either observe them later that night or in the next few nights.
The system works very well. We end up being able to observe things that occur out of the blue while also making sure we get the best science projects completed.
Lisa - I doubt we'll get a close-up view, the thing is about the size of a car, so is very small. I do think we'll figure out what it is though, either the body of an old rocket or an actual asteroid.