Some equipment around the observatory is thirty or more years old. As you would expect, keeping it running can be a challenge.
There are two ways of dealing with this old equipment… Replacing it with something new is the preferred way. When it becomes difficult to locate spare parts, when it breaks down too often, just replace it with new gear. For much of the equipment this is the usual answer and is often a major part of the job.
Some equipment is not so easily replaced. When replacement would require wholesale redesign of a system it becomes more of a challenge. Sometimes the only choice is to keep that old gear running.
This is the case with our servo amplifiers. Twelve amplifiers supply the power that drives the telescope, one amplifier for each motor. Eight amplifiers and motors drive azimuth, four drive elevation. Three hundred and seventy tons moved by twelve relatively small DC motors. While much of the telescope control system was recently replaced, it was decided to keep the old servo amplifiers.
You might notice that these servo amplifiers are just a wee bit critical.
It is always another little problem. But, on occasion, a problem is an excuse to have a little fun while getting the job done.
Enter an old WYKO interferometer with a composite video output. The gear is a critical piece of kit used to monitor the deformable mirror used in the adaptive optics system. The images from the interferometer are analyzed by a windows PC with special software. Windows, as in Windows 98!
Updating this computer has been on our to-do list for way too long. Time to get it done… When installing the new computer and video board to update this system I found that the video quality was quite bad. It would tear about halfway down the image, something wrong with the horizontal sync? Looking back it was not great on the old system, but usable. On the new system it was just not going to work.