Chili - 7 - San Pedro, Salt Mountains & Valley of the Moon

Saturday, 13 December 2025

On our drive from the Calama airport to San Pedro de Atacama, we stopped at an overlook just outside San Pedro to view the Salt Mountains.

Volcan Licancabur at sunset as viewed from our hotel.

Tuesday, 16 December 2025

On our last day in the Atacama we had a tour to the Valley of the Moon (Valle de la Luna) in the Salt Mountains just west of San Pedro.

Salt embedded in the rock.

The salt in bricks used to make houses. You know it's dry when your bricks contain salt!

Evaporites.

Abandoned salt mine.

Salty rocks

Looking down the valley - classic view.

Layered cliff.

Sunlight on sand dune.

Rocks and dunes.

Sunlight on dune - redux.

Licancabur from Death Valley (Valle de le Muertes) overlook.

Chile - 6 - Day of the Lagunas

Monday, 15 December 2025

Today we visited three lagunas (lakes) with spectacular views and wildlife.

Laguna Chaxa

The salt flats south of San Pedro de Atacama are picturesque and a good place to see all three species of flamingos that inhabit this part of Chile (Andean, Chilean, and Puna/James).

Photogenic flamingos - just a few of the many photos I took!

Another shorebird at Laguna Chaxa - sanderling???

Lagunas Miscanti and Miñiques

Laguna Chaxa was at about 8000 ft elevation. We then drove to two high altitude lakes further south from San Pedro. Lagunas Miscanti and Miñiques were at 13,500 ft - an elevation that was clearly cooler and less oxygenated!

Vicuñas at Laguna Miscanti.

Laguna Miscanti.

This grass-like plant near Laguna Miscanti liked to grow out in circles.

Chile - 5 - El Tatio Geothermal Field & More

Sunday, 14 December 2025

We left in the wee hours of the morning and drove through the cold dark from San Pedro de Atacama to see the El Tatio geothermal features at their most impressive - when the sun's light first peeks over the Andes to illuminate the steam. The 50 mile drive is over a very rough road and takes about 1 1/2 hours. The 14,100 ft elevation made it particularly cold (not to mention literally "breathtaking") - the temperature when we arrived was -9°C (16°F), but quickly warmed to above freezing with the morning sunshine.

Most of the El Tatio geysers are only about 1 m (3 ft) high, and easily obscured by steam.

Steam vents & fumaroles against the Atacama desert background.

A steaming hot spring.

Hot spring run-off.

We made several stops on the way back from El Tatio: a breakfast stop, two viewpoints with interesting lagoons, salt mines, and wildlife, and the village of Machuca for a rest stop (with "facilities").

Andean Gull at our breakfast site along a wetland near El Tatio.

Overlook near the Rio Putana.

The "Five Fumaroles" volcano - never did get the name.

"Flamingo Lagoon" near Machuca.

Vicuñas at the Flamingo Lagoon.

Same vicuñas as above - it's unusual for me to get wildlife facing me, instead of facing away. Some day I'll make a calendar "Great Wildlife Butts of the World".

Chile - 4 - ALMA

Tuesday, 16 December 2025

ALMA (Atacama Large Millimeter/submillimeter Array) is an array of 66 radio telescopes in the high reaches (16,500 ft above sea level) of the Atacama Desert in northern Chile. While the radio dish antennas are that high, the offices, labs, control room, and maintenance facilities are at a much friendlier 9,000 ft. Going to the higher altitude requires special training and a long, slow drive - not to mention a good reason to go up there.

The office and labs for ALMA are in this building.

The control room - no observations were being made today.

A detector/receiver that hangs over the top of the telescope dish. This one was in a clean lab for maintenance.

The break room / lunch room has an amazing view over the Atacama salt flats.

This 12-meter Japanese radio antenna is down at the lower level for maintenance. The United State, Europe, and Japan have each designed and built telescopes for the array. Each antenna weighs about 100 metric tons. The transporter in the background is used to move the dishes much like a giant forklift.  

One side of the transporter. A transporter weighs about 135 metric tons and has 28 wheels on 14 axles.

In between the two arms of the transporter.

Looking at the driving end of the transporter. The antenna will fit into this slot for transport. A large generator in the middle supplies power during transport - it is essential that the receiver cryogenics be maintained at all times.

One of 14 wheel assemblies.

Chile - 3 - Optical Observatories, Daytime

Friday, 12 December 2025

We toured two large optical telescopes on Cerro Pachón - the Vera Rubin and Gemini South Observatories.

The observatories on Cerro Tololo and Cerro Pachón share an entrance gate that is 41 km (25.5 miles) from the Rubin Observatory. At the gate you get a distant view of Cerro Tololo.

Cerro Pachón as seen from Vista Sidney Wolff. From left to right: SOAR, Gemini South, Vera Rubin.

The road splits at Vista Sidney Wolff. The road that goes towards the upper left goes to Cerro Tololo. The road going towards the bottom left comes up from the entrance gate. The road heading towards the bottom middle and left is the road up to Cerro Pachón.

Cerro Tololo and the road from Vista Sydney Wolff as seen from the Rubin Telescope.

Vera Rubin Observatory

The telescope at the Vera Rubin Observatory (formerly called the "LSST" - Large Synoptic Survey Telescope) is designed as a survey instrument - a wide-field imager that will cover the entire sky once every three days. It has the world’s largest digital camera (3200 megapixels, 20 terabytes of data every night). When fully operational, it will excel at detecting fast-moving objects such as comets and asteroids. When we visited in 2019, it was still under construction.

Closer view of the Rubin Observatory as we climb Cerro Pachón.

Full view of the Rubin Observatory.

Rubin control room.

Cables beneath the telescope.

The huge camera (3,400 megapixels) is mounted in front of the 8.4 m (331 inch) mirror.

The primary and tertiary mirrors are barely visible behind the SUV-sized camera. At the upper left is the calibration disk - it is imaged at the end of every observing session to create a reference image.

Gemini South

There are two other observatories on Cerro Pachón: SOAR (Southern Astronomical Research) and Gemini South. We had a great visit of Gemini - many thanks to Brian Miller for a great tour.

SOAR (left) and Gemini (right) Observatories as seen from the Rubin Observatory. I am wearing the required safety equipment for visiting some of the telescope sites - hard hat, safety vest, long sleeves, long pants, and closed toed shoes.

A better look at SOAR and Gemini.

The Gemini control room.

A total view of the telescope. The secondary mirror is at the top of the photos; the detector array is at the bottom; the primary mirror is hidden in the blue supporting structure.

A carousel of various detectors behind the primary mirror.

The primary mirror is 8.2 m (323 inches) in diameter. The telescope is optimized for detailed deep-sky observing, especially in the near infrared.

As we were leaving, clouds were building behind Gemini - not a good omen for the night's observing.