May 16, 2013
Going Observing: Peering Into The Sky
For centuries, astronomical research was conducted by peering into the eyepiece of a telescope and recording, often by hand, what was seen. And while this has not been the dominant method of research for decades, it is still the image that comes to mind when asked to describe the work of professional astronomers.
There are space-based instruments, such as the Hubble Space Telescope, that are operated remotely, and take pictures using CCD cameras. But what about astronomers on the ground; how do they spend their nights?
I, myself, am spending a couple of weeks observing on the VERITAS array in southern Arizona. In a forthcoming post I will describe this observatory more specifically, but for now I really want to focus on what astronomers and physicists spend their nights doing. Naturally, not every telescope or observatory is the same, but there are some aspects of observing that will be common to most.
First and foremost, rarely do astronomers look through the eyepieces of telescopes; at least, not when the purpose is to conduct research. These days, the data is recorded with computers. The specific imaging instrumentation will vary widely depending on the type of light (radio, optical, X-ray, etc.) that is being observed.
In the case of optical observatories, CCD cameras (similar technology) will be used to record the photons. Computers then compile the data together to create visual maps of the sky. The specific technology used to capture the light will be specific to the waveband of interest, but essentially the same procedure applies across the electromagnetic spectrum.
To operate the facilities, astronomers usually sit at computers in a control room, like that pictured above at VERITAS. Here they monitor where the telescope is pointing, the collection of data, the status of the hardware, the changes in the weather, and dozens of other parameters. Depending on the complexity of the telescopes being operated, anywhere from one to half a dozen scientists may work to run and oversee a single experiment.
Once the data is recorded, the files are processed offline using specially developed software. The procedure is essentially the same for all types of telescopes, but the details can vary considerably. In the end, though, the goal is to compare the signal coming from the source of interest to the background light. From this, various pieces of information can be deduced, such as the source brightness, how the source changes over time, how the brightness changes as a function of energy, etc.
As our understanding of the universe has evolved, and our technology has improved, the ways in which we conduct astronomical research has similarly advanced. Gone are the days of peering through telescopes with the naked eye, and making hand drawings of what we find. Rather, we use high performance computers to take, analyze, and interpret the universe.
Featured Image Credit: Photos.com