miniTAO Full-Remote Operation Started

miniTAO has many difficulties on its operation because of its high altitude environment (5640 m) and long distance from the base camp at San Pedro de Atacama (about 80 km).

The round-trip drive between the base camp and the summit observatory takes about 4 hours. There are many dangers like snow coverage, rock fall, and harsh weather along the way. The oxygen concentration on the summit is only about a half of the normal living place. Cosmic-ray exposure is also one risk at the summit. The operations and observations in such environment sometimes threaten our lives. Then, for safe and efficient observations, wireless network has been established between the base and the summit for remote operation. It connects the way of about 50 km (linear distance) with radio as shown in figure below.

Nowadays, remote observing systems are often used among the world observatories like the Subaru telescope in Hawaii and the ASTE telescope in Atacama in Chile. Ahead of these observatories, the University of Tokyo had been operated the MAGUNUM telescope at the summit of Haleakala in Hawaii from Japan totally remotely.

▲Dome of MAGNAUM telescope at the summit of Haleakala in Hawaii. It had been operated from Dec. 2000 to Dec. 2008.

Some equipment is required for remote observing system. In the miniTAO remote observing system, highly accurate, stable and reliable network system was constructed based on the experiment of the MAGNUM telescope.

At first, two pairs of the parabola antennae connecting the summit and the base (a total of four antennae) were built at both places. One pair is prepared for the backup line used when the main line is in trouble.

At first, two pairs of the parabola antennae connecting the summit and the base (a total of four antennae) were built at both places. One pair is prepared for the backup line used when the main line is in trouble.

There are also some systems for handling the emergency, like (1) a function which close the dome slit in sensing the disconnection between the base and summit, (2) a system against power failure which automatically shuts down the machines at the summit by the exhaustion of batteries, (3) an alerting system which judges and informs us of bad conditions for the telescope, like strong wind and high humidity.

▲Various systems supporting remote observations.

As mentioned above, there was a loss of observing time attributed to the dead time of about four hours trip between the summit and the base. However, by this establishment of remote observing system, observing efficiency will be much improved because the dead time become utilized as the observing time.

▼Operating time table before and after completion of remote observing system.

※Typical case is shown here.Actual observing time varies depending on starting and finishing of twilight. ※Mid-infrared observations are sometimes conducted in daytime.

In this campaign, 15 ANIR programs of 156 hours and 8 MAX38 programs of 153 hours have been conducted. The total observing time increased about 20% compared with the previous campaigns. In addition, MAX38 observing time especially increased because the remote observing system enables us to utilize the daytime observable time. (*In actual operation, it is sometimes required to go to the summit for emergency response to the troubles of the telescope, dome, and power failure or requirement of on-the-spot observations.)

Highly sensitive observations or utilizing new atmospheric windows require the site with better condition (often harsh environment for observers). Ultimate site is satellite telescopes. However, there are many difficulties like expensive launch cost, limited observing time, long development time, maintenance difficulty, etc. Taking into account these matters, ground-based observatories will not disappear. It is likely that the mutual cooperation of ground-based observatories and space observatories will bring fruitful results. For such successful achievements, remote observing technics of ground-based observatories will be much more important and necessary.