Tuesday, 7 October 2008

Queuing up

In the old days, life as an astronomer was wonderful as long as you enjoyed travelling. Every six months or so you'd write science cases for obtaining observing time at various telescopes around the world and if the various peer-review panels accepted your proposal, off you'd go to the telescope to carry out your project. As a student and subsequent post-doc I was fortunate enough to visit the US (including Hawai`i), Australia and South Africa to use various telescopes.

Although this still happens many observatories are switching to a new mode which is far more efficient. I just happen to work at one which took the lead in this new method - queue observing.

The old "classical" scheduled runs worked well because you were at the telescope and essentially controlled your experiment, but if your run happened to coincide with a period of poor weather or serious technical problems then you were almost certainly screwed.

The new mode is called "queue scheduling" or "flexible scheduling". Briefly, once the time allocation panel approves a proposal for telescope time the astronomer prepares his or her programme using software supplied by the observatory and then submits it to a database, or the "queue". At night, these programmes are pulled out of the queue and run. The astronomer then receives their data via the internet.

The advantages are numerous. The various science project in the queue will more often than not have particular weather-based requirements. For instance the seeing needs to be good in order increase sensitivity or detect small detail in images or the observations require dry atmospheric conditions. Alternatively some observations can be done in bad weather because sensitivity or stable conditions are not so important. Which observations are done on a particular night are then driven by the weather and we no longer have nights wasted because of inflexibility. The database also allows those projects which are rated highly on a scientific basis to be put at the top of the queue and so are given the best chance of being completed.

This has reduced the need for astronomers to travel to observatories. Some love this, others don't! It hasn't completely removed the need for visiting observers though and we still receive many of them. For the more technically challenging projects or highest rated projects astronomers still visit and their project is given priority while they're observing. They still get to carry out their experiment but while conditions are not suitable for their project they carry out observations from the queue for others. When visiting observers aren't present then of course the observatory staff do the observing.

It's a win-win situation as far as I can see. Money is saved, the best projects are almost certain of being completed, we can still train visiting students and the highest quality data are almost certainly guaranteed for those that need that.

If I were still in the UK though I might think differently as I adored travelling, I still do in fact! Well, I guess it would have forced me to write better proposals!

(Picture credit: http://en.wikipedia.org/wiki/Image:Bus_Queue.jpg)

No comments: