Janet and I left the hotel right after breakfast and got to the observatory about 9:40.
Mr. Ángel Vásquez, Director of Telescope Operations, came to meet us at the parking lot
by the guard shack and personally drove us to the observatory. Mr. Vásquez was born in
the town of Arecibo and has been at the Arecibo radio observatory for 38 years. He showed
us a wall full of photos of famous visitors.
The reflecting dish is 1000 feet in diameter, built into a natural depression in the mountains.
You can barely see the dish from the center, but the feed assembly is prominent. It is suspended
over the center of the dish from three cables going to towers at the perimeter of the dish.
You can see the top of one of the towers at the lower left of this photo. Compare this photo of
the catwalk with the two human figures to the photo at the top of the page to get some feeling
for the scale of this installation.
We got to see the giant klystron transmitting tube that was used for the recent amateur radio
moonbounce operation on 432 MHz. Some radio amateurs enjoy the challenge of bouncing radio signals
off the moon and listening to the echoes. That normally takes a transmitter with maximum legal power,
a huge antenna and a very sensitive receiver. But with Arecibo on the other end of the circuit,
even a very modest station can communicate via moonbounce.
We also got to see the 1950’s-era console for the 432 MHz transmitter. They used waveguide
for feedline for the moonbounce operation. That's Sr. Vásquez on the left.
Here's a corner of the control room with operator Efraín. In addition to the information
on all the monitors he can see the dish through the large window behind him.
One of the monitors out of the picture behind him shows some technicians doing maintenance inside
the "dome", the bulbous thing that hangs from the feed assembly over the dish. Inside the
dome are antennas as well as equipment. He told me the dome has three stories, which again
gives some sense of the size.
The equipment racks shown at right hold nine HP8648 signal generators, which I helped
design when I was at HP.
Arecibo is involved with SETI, the Search for Extra-Terrestrial Intelligence. This rack
records hundreds of channels of information while the dish is being used for other things.
The data are then sent via the Internet to thousands of volunteers whose computers process
the data when not otherwise in use.
After the tour, Janet drove me back to the hotel in Hatillo where I retrieved my bike
(the morning receptionist was much more personable than the evening one) and did the ride
a couple hours after everyone else. The first and last parts of the route were on busy PR2,
but the part in the middle was quite nice. After leaving PR2, there was a pretty stretch on
a wide stone-paved path next to the ocean. At the end of the path, where you turn left on PR681,
there was a convenience store and an ice cream shop. I bought an Arizona juice, ate my PB&J
sandwiches and finished with two scoops of coconut ice cream.
Dinner tonight was at a Longhorn restaurant next to the Hiatt hotel where we are staying.
I don’t think anyone actually had steak, though.