The McDonald gun shooting incident

On the 5th of February, 1970, a rather bizarre incident happened at the McDonald Observatory, at the 2.7m reflector telescope. A newly hired employee was apparently very dissatisfied with his new job, or, something else was very wrong. Whatever the reason was for said person to be angry with the world, he had decided to take it out on the telescope itself.

Bringing with him a 9mm gun, he first fired a shot at his supervisor, and then fired seven shots, point blank, into the primary mirror of the telescope, no doubt hoping to shatter it. Alas, big chunks of glass like telescope mirrors, do luckily not break so easily, so the bullets merely created small holes in the mirror. Not being happy with this outcome, he also attacked the mirror with a hammer, but to no avail. The mirror did still not shatter. Shortly after, the person was subdued by the rest of the astronomer staff, rushing to the site.

The primary mirror of the 2.7m telescope at McDonald Observatory. The bullet holes can clearly be seen. Photo credit: McDonald Observatory.

The primary mirror of the 2.7m telescope at McDonald Observatory. The bullet holes can clearly be seen. Photo credit: McDonald Observatory.

When the sheriff arrived, the employee was arrested and later committed to a mental health institution. In the report following the incident, the sheriff, clearly being unfamiliar with telescope designs, stated that the mirror had indeed been destroyed as it had a big, circular hole, right in the middle! Thus, it was allegedly reported widely that the telescope had essentially been destroyed. However, most astronomical telescopes do in fact have holes in the middle of the primary mirror, as it allows you to attach instruments to the bottom of the telescope (the Cassegrain focus). Because of such erroneous stories, the director of the observatory, Dr. Harlan J. Smith, released a report setting the facts straight:

“… The harm suffered by the mirror from his bullets and his several preliminary blows with a hammer was extraordinarily small. The damage is limited to small craters about 3 to 5cm in radius, which reduce the light collecting efficiency by about 1 percent and introduce a very small amount of diffraction …… Astronomical observations of all types are essentially unimpaired by this tragic episode; the telescope resumed its observing program the following night, producing some of the best photographs (of quasar fields) so far obtained with this instrument in its first year of use.”

The full report can be read here.

This is likely the only telescope in the world who has been a victim of a handgun assault, and it will hopefully stay this way. The bullet holes can still clearly be seen in the primary mirror. Fortunately, no people were hurt during this rather tragic incident.


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