The order of visiting was the 150ft Solar telescope, then the 60" telescope building, then the Snow telescope, then the Fairbanks-Morse RE engine, then the 100" telescope last. Details of all these items can be had on the Mount Wilson website, links to which are available from many places on the web. There is also a web site run by the Mount Wilson Observatory Association: http://www.mwoa.org This last site has a good aerial photograph of the Mount Wilson site that gives a good perspective on the overall layout of the facilities.
The 150ft and 60ft Solar Tower Telescopes are purely for research into the Sun, and are used to track the sun and transmit an image down the high towers to an image plate in the control room or a lower facility which is housed in a deep hole under the control room. The deep holes are about 75ft deep with a spiral staircase which we didn't take the opportunity to do down!
Larry Webster kindly gave us an excellent guide talk on the 150ft telescope while we were there, and his assistant/operator Pam was able to let us have a look at the images and instruments, something that Rita was quick to take her up on.
The 60" telescope is a 'proper' reflecting telescope with a mirror that is 60" across as its name suggests. These mirrors are cast glass with a ground surface which was silvered but is now aluminised. The weight is the 60" mirror is about 5000 pounds. The 60" telescope is fully functional but is not used a much now as the larger 100" which we were to visit later.
The Snow Telescope is a horizontal axis reflecting telescope which has its main parts lating down and fixed, so that its scope of coverage is limited. An adjustable mirror captures the image and reflects it to another mirrow which then sends it back 150 feet to another mirror where is it sent to a viewing desk. Most of the structure is in good condition, but some of the housing was being reinforced or repaired as we were there.
The weather was nice when we arrived as can be seen from the photo's of our arrival, but the site had had snow on the Saturday while we were at Tulare, and it was laying quite thickly in places as we walked around. The buildings are unheated, so we started to feel the cold after a while. I was in shorts, but was OK until almost the end when I started to feel the chill.