Massimo's photoblog

Mondovi, Italy (Aug 14. 2006)

On Sunday I will be again on the road... well, in flight, to Arizona, for a new run with the MMT telescope and a refurbished version of the MIRAC infrared camera. Digital cameras used in astronomy are not that different from the digital cameras used in photography. The difference is not in the number of pixels (the camera I am actually going to use has only 256x256 pixels which is a mere 65kpix, albeit there are huge format astronomical cameras), but rather in terms of sensitivity and wavelength range. Sensitivity is obviously essential to observe faint astronomical objects and to take full advantage of the huge optics provided by the telescope (the primary mirror of the MMT has a diameter of 6.5m aperture). For this reason astronomical detectors are cooled to liquid nitrogen or liquid helium temperatures to reduce as much as possible their dark current. Wavelength range is also important because there is a lot of science that can be done outside the range visible by the human eye. For example the camera I am going to use next week is sensitive to the mid-IR range, which is where thermal radiation is emitted. At mid infrared wavelength the human body would glow as a light-bulb (that’s me in the photo), so images at mid-IR are more like thermographs, than regular film-based infrared photography. See, for example, the NASA infrared zoo.

The panorama above is the castle in Mondovi, a nice town in northern Italy.