Posted on 17 January 2011 at 14:22h

I've been noticing a very bright planet visible in the South east every morning for the past couple of weeks so apparently its Venus and the one in the evenings is Jupiter. On Thursday I started my journey from Flekke to Cardiff to attend a meeting about setting up an online physics course, to cut a long story short i was still travelling on Friday morning and was able to see Venus from the plane. It was just before sunrise and was the only thing visible in the morning sky the rest being lost in the emerging blueness of the suns scattered light. it was such an impressive sight that I took a photo with my phone (switched onto flight mode of course). As you can see the photo is not very impressive although you can just make out the planet, its at about 2 o'clock. How is it that  to my eyes the planet looked very bright but on the photo its not?  A fweek ago i was commenting that  when one takes photos of the aurora the result is usualy more impressive than reality this is the opposite. I guess its something to do with the non linear response of the eye (sounds convincing anyway). I don't know how the ancient astronomers judged that some stars were x times brighter than others I can tell which are brighter but struggle to say how bright.

I thought I'd try to zoom in on Venus to see what is revealed. The result is quite interesting although being colour blind I might lose some of the subtleties of the image. One of my students this year has written his EE on how to use a digital camera to measure the intensity of light from point sources like this. Here you can see that there is infact guite a lot of information to work with.