| Description | Monochrome photographs, taken during the first reflector testing. The reflectors were pointed horizontally at a distant gum tree on which a lamp had been mounted. After each of the 252 mirrors on each reflector had been adjusted individually, Jupiter was tracked over a wide range of elevations.
Communication from Prof. John Davis, 19 February 2007:
'What the [two larger] pictures show is the perspex graticule we mounted at the focus of a reflector to give us a scale for aligning the images from the individual mirrors into a single "blob" of light - and then for photographing the images of Jupiter to observe what happened when the reflector was tilted in elevation. [One of them] shows the assembly of individual images but I am not sure what the scattered flare of light is - the comment [on the back] regarding "by garage lights" suggests that it is an out-of-focus reflection of lights in the garage where the reflectors were housed - by having them on, the graticule can be seen. In the [smaller] pictures, which show various image assemblies, you can just make out part of the graticule in some but not as clearly.'
'I can't tell you what the individual image assemblies are except that they were taken during the alignment process using the lamp in a distant gum tree! I went through that alignment process of over 500 mirrors (for the two reflectors) more times than I care to remember as, in use, they gradually became mis-aligned. I accepted responsibility of re-doing it every few months with the aid of students!'
'One telling point regarding the comments is "Red 119 mirrors" which almost certainly means we had taken the faulty mirrors off the reflector at that stage. We mounted all the mirrors on each reflector before removing the protective layer and the alignment tests couldn't be done with it on. So it looks as if the faulty mirrors were removed a bit sooner than I thought.'
The first reflector tests revealed substantial technical problems for which there were no simple solutions. |