Engineering the big Telescopes [Gallery]

The Y-shaped layout of the VLA is clearly visible, as are the double-tracked railroads next to the antennas. This is the most compact configuration, the one with the largest field of view, but lowest resolution.

View down one of the arms of the VLA. The double-tracked rails with their 90-degree turnoffs are clearly visible, as is a transporter under one of the antennas.

This picture shows the antenna maintenance building called the barn as well as the antenna test pad just outside. Both of the two transporters are visible as well.

A beautiful evening view of the VLA, with rare clouds in the sky.

The classic view of the LBT with opened enclosure, the two binocular mirrors side-by-side, reflecting the evening sky. The huge vents protruding on the bottom are a part of the air conditioning system.

View-angle view of the two mirrors from the inside. The two Large Binocular Cameras can be clearly seen in the primary focus. The picture has been taken when no additional instruments had been installed between the two mirrors.

Another view of the two huge mirrors, now looking towards the horizon. The white handrails on the mirror platforms put the size into perspective. The silver rings/holes on the inside of the mirrors are the mounts for the instruments.

The beefy elevation mount and its drive.

One of the two MODS instruments mounted in the primary focus, right behind the mirror.

ESO’s VLT on the top of Cerro Paranal in Chile. The enclosures of the four 8.2 meter unit telescopes are clearly visible. The white-panelled area is where the auxiliary telescopes can move.

A view on the platform, towards the unit telescopes, just after sunset. The VLT clearly wins the competition regarding the online gallery with the best images. Check it out!

Inside the enclosure of a unit telescope.

Another view of a unit telescope, this time at night. The AO star lasers are clearly and impressively visible.

Two of the smaller auxiliary telescopes. They can be moved around by truck.

The tunnel that contains the delay lines for the VLT Interferometer that ensures a common length of the light path when interferometrically combining the four unit telescopes.

The Paranal Express. These cartridges move on rails in the tunnel to adjust the length of the delay lines for the interferometer.

The Effelsberg dish peeking out of its valley in August 2019.

Another view of the dish and the intricate steel mesh that backs up the surface. You can also see two of the four holes where support beams for the primary focus cabin connect to the structure. One of these four contains a walkway for personnel to access the primary focus cabin when the telescope is in horizontal position.

This picture shows the essence of the homologous design of the dish. Two major (rectangular) beams hold the counterweight and central point (directly above the red motors at the bottom of the picture); from there, a ring of smaller round beams provide a circular support for the dish. The elevation axis is between the two “huts”; the gear ring that moves in elevation and its driving motors are clearly visible. Not that this ring does not carry any of the load of the telescope.

Yet another view of the underside of the telescope. Once again, we can clearly see the two box beams that hold the counterweight from which the ring-style round beams support the circular dish.

One of the four bogies that hold the 3,200 tons of total mass of the telescope. The bogies also hold the motors that provide rotation in azimuth.

The elevation ring gear and its drive.

This is the central pin, viewed from underground. The cables that come from the receivers are clearly visible. By the way: the telescope’s rotation in azimuth is limited to 480°, otherwise the cables get tangled.

The primary focus cabin. The lower/right side you can see the active secondary mirror. A flap in the center of the mirror can be opened, and the primary focus receivers can be lowered towards the dish. You can also see that a motorized lift was attached to a bar on top of the cabin; it is used to lift equipment from the ground to the dish. After the cable has been reeled in mostly, the antenna is moved in elevation, and the cable is reeled out again to lower the lift’s load onto the dish.

This is the secondary focus cabin, currently with a closed top because no observation is going on. You can also see that some of the panels have been removed for maintenance reasons.

The telescope in almost vertical position.

The view from the control room.

The observatory on the Pic de Bure at around 3,000 meter in the Provence. You can clearly see the two axes for moving the telescopes.

A closer view of the Pic de Bure. Like the previous picture, this one was taken while I was flying over the observatory with my glider in 2018.

A beautiful view of some of ALMA’s 12 meter antennas in the winter, with some unusual humidity in the (high) atmosphere.

Another overview picture of ALMA. The photo looks almost artificial because of the very dry air and the very crisp colors.

If you look closely, you can spot a difference between the two antenna types.

This shows the ALMA Operational Support Facility, or low site, at 2,900 meters. In particular, the picture shows the antenna maintenance facilties (bottom left), the hotel and control facilities (right and up from the center), the antenna construction camp (far right) and the garage for the two transporters (top right corner of the installation).

I can’t tell whether this is Otto or Lore, but it clearly says Scheuerle all over the place. You can see how all the wheels can be controlled separately, allowing the vehicle to move in all directions. The inclined beams with the hydraulic cylinders are used to lift the antennas from their pads.

One of the transporters carrying an antenna down to the support facility.

Technicians working on the receiver cabinet in the primary focus.

The receiver cabinet with the frontends/receivers for the 10 different ALMA bands. You can see various different kinds of antennas or horns, depending on the wavelength of the band.