Monday, Oct 17

Since I will have several hard driving days coming up as I work my way across Texas, I decided to have a couple of relaxing days in Arizona first. I have visited Tucson a number of times before and really enjoy the city. I always find something new to see and I’m rarely disappointed and so it was today.

I started the day going about 30 miles northeast of the city to drive the Mount Lemmon Scenic Byway. The name tells you most of what you would want to know about this road that climbs from the hot desert floor to the summit of Mount Lemmon, at around 8,000 feet, and provides some splendid views on the way. The video is the best way to see this drive and is available, together with the map of today’s route, here.

After this I returned to town to do a nerdy tour of the University of Arizona’s Mirror Lab. The University of Arizona has one of the largest and most respected astronomy/astrophysics departments in the US and one of its professors, Roger Angel (born in the UK), invented and developed the technology to make the largest telescope mirrors in the world. When I saw that they offered 90 minute tours I thought “wow, that sounds interesting” and “how can it take 90 minutes to tour a mirror making facility?” The tour was, indeed, very interesting and the 90 minutes turned out to be just enough time to explain the process and take us through the lab.

The facility can make mirrors up to 9 metres (29.5 feet) in diameter but they are too big to transport on US Interstate highways so they limit themselves to 8.4 metres (27.5 feet). I won’t go into too much detail but the glass used for one mirror takes a year to be made, the casting of a mirror takes three months and the final polishing and testing takes another year. They are currently making the seven mirrors that will go into the Giant Magellan Telescope which is scheduled to begin operation (with just four mirrors) in 2022 and will make its 1.5 Terabytes of daily data available over the Internet for anyone to analyze.

After all of that excitement I headed to a different hotel south of Tucson to rest up 🙂

There are many scenic viewpoints and parking pullouts on the Mount Lemmon Scenic Byway. This shot is looking back towards Tucson which can just be seen in the V of the canyon.

The amazing roads that are built in rugged countryside allow me to make these trips. Here is a great view of this road and rugged countryside.
One of many hoodoos that are seen on Mount Lemmon.
There is no mirror being cast at the moment in the University of Arizona Mirror Lab but this is the base of the furnace where the glass is melted and formed, over a period of three months, while the furnace spins.
There is a mirror being polished in the white cylindrical machine at middle right below. Every few days it is removed and positioned at the base of the tower in the foreground for optical testing. The mirror and equipment are large (see the full sized trash can at the bottom right) but its surface must be polished to a precision of less than 25 nm (about the thickness of 100 molecules).