Lick Observatory has historically played a significant part in our infrared imaging story. During the 1920s and 30s scientists at the observatory experimented with infrared photography, as I mentioned in an earlier post. The infrared comparison photos that WH Wright took of Mars in 1924, which proved that Mars has an atmosphere to speak of, were taken there (and are included in the Infrared 100 exhibition at the RPS in Bath this month). If you're interested there is a 2006 paper on the Lick photographs in the Journal of Astronomical History and Heritage (Vol 9, No 2, p 181-184) but it's not available online.
And the 48 hours? There's a delicious coincidence which brings me to another historic infrared photograph taken at another famous American observatory, Mount Wilson. In this case the date is 1930, the photographer is HD Babcock and it is a blurry and unassuming image of some objects on a shelf. It is also the first photograph taken in total darkness.
|Infrared photograph taken in total darkness by HD Babcock in 1930|
So here we have the darker recesses of the universe, one distant and one very close. Both unobservable except using infrared imaging and both taking 48 hours to shoot.