Shooting for the stars

Just like any other field of science, astronomy has had its share of colorful characters over the years. One of the more recent ones was no doubt Fritz Zwicky (1898-1947). Zwicky was a Swiss astronomer, who came to California Institute of Technology as a graduate student, and ended up as a full professor, spending the rest of his life in Pasadena.

Zwicky was known for his antics and sometimes odd behaviour, both during social gatherings, but also during scientific work. In terms of the latter, one could probably consider him thinking very far outside the box. One of the more famous episodes happened during a night of observing with the 200″ Hale telescope at Mt. Palomar Observatory;

One of the challenges when observing objects close to the Earth, is the ability for the telescopes to track fast-moving objects. You want your telescope to be able to move fast across the sky. At the same time, it needs to move smoothly enough so that the object you are tracking stays on the same spot on your detector. This is far from trivial, and even with modern telescopes, accurate tracking of near Earth objects can be quite challenging.

In the days of Fritz Zwicky this was even more true than today. And understandably it was of interest to determine just how fast and accurate it was possible to track objects with the Hale Telescope. Zwicky took an somewhat unconventional approach to testing this.

The 200-inch Hale Telescope at Palomar Observatory

The 200″ Hale Telescope. Photo credit: Palomar/Caltech.

Together with his night assistant, Ben Traxler, he conducted an experiment, where several shots were fired with a rifle out through the dome slit. Zwicky would then attempt to track the bullets with the Hale Telescope. There are no reports as to how successful this experiment was, but  it is definitely an example of Zwicky’s outside-the-box thinking. The incident did however, result in Zwicky being temporarily banned from using the Hale telescope.

On the other hand, his way of thinking did lead to groundbreaking research in supernovae amongst other things. He also proposed several ideas that were subsequently confirmed, like neutron stars, gravitational lensing and dark matter, many of which were not taken seriously at the time.

To my knowledge, Zwicky has been the only astronomer who was literally “shooting for the stars”. Which should probably be considered a good thing.

Thanks to Barbarina Zwicky for providing details for this story.

Rest in peace

Astronomers are normally very dedicated to their work, and many an astronomer spend an entire lifetime unravelling the mysteries of the Universe. When they pass away, some desire to be buried at the places where they lived their lives, rather than in an anonymous cemetery somewhere.

When the new Allegheny Observatory was built, a storage vault was constructed in the pier of the middle sized telescope. This area is one floor below the main basement and it was quickly decided that it was much too damp to store anything of value.

James Keeler, who was the second director of the Allegheny Observatory had left to be the director of the Lick Observatory right before construction began on the new Allegheny Observatory. Unfortunately Keeler died in 1900 at the young age of 43.  Keeler’s widow wanted to have her husbands remains interred at the Lick Observatory but James Lick was already buried there.  The University of California Board of Regents decided that “The great telescope should stand sentinel over James Lick’s body alone.”

John Brashear, who was busily constructing Allegheny Observatory, then decided to make the storage area under the pier into an ornate crypt.  James Keeler was the first person interred at the Observatory crypt in 1906, but not the only one. He was followed by John Brashear himself and his wife Phoebe, who are together in the same burial urn.  James Keeler‘s son Henry died at the very young age of 25, he was buried in the same notch as his father in 1918. James Keeler‘s widow lived until 1944, she died in Arkansas Kansas and was buried all by herself.  Her great, great grandson found her remains and brought her to the Observatory to be reunited with her husband and son on April 15th, 2007.

Allegheny Observatory is not the only observatory to double as a burial ground for astronomers. In Australia, the astronomer Walter G. Duffield was instrumental in the decision to build a solar observatory on the top of Mount Stromlo, called the Commonwealth Solar Observatory, on the site that today hosts the Mount Stromlo Observatory.

Duffield was appointed first director of the Commonwealth Solar Observatory in January 1924, but as a chronic asthmatic, he died of pneumonia on 1 August 1929 at Mount Stromlo while work was still in the preliminary stages. After his death he was put to rest on the western slopes of Mount Stromlo, from which he is overlooking the observatory. His grave is only a short walk from today’s observatory site.

Also Percival Lowell, the founder of the Lowell Observatory, is buried on Mars Hill, near the observatory he helped construct.

No doubt there are more astronomers sleeping the long sleep at other observatories around the world. Here, they can forever watch over the buildings they helped construct, and follow how we keep pushing the boundaries of our knowledge, building on their pioneering work.

The Allegheny lens napping

Astronomical observatories were not always as big as the huge constructs we see today, like the ESO VLT in Chile and the Keck Telescopes on Hawaii. Back in the day, they were much smaller.

Pittsburgh’s Allegheny Observatory has the 13″ (33cm) Fitz Refractor, which was the third largest in the world when it was built in 1861. A 13″ lens is not all that big, and, in fact, it is possible for a single person to carry it away. This was what happened in 1872,  when a thief stole the lens and held it for ransom.

The old story goes that Professor Samuel P. Langley received a letter from the thief that stated that he should meet with him in the woods behind the observatory at midnight or he would never see his lens again. Supposedly Langley did meet with the thief and told him that no ransom would be paid. Prof. Langley and the thief the parted ways, without having resolved the situation, and the lens was still missing.

It seems that a newspaper investigative reporter from the Pittsburgh Leader, who covered the case, was responsible for the eventual recovery of the lens. His investigation allegedly prompted the lens-napper to flee after a few months, for fear of discovery, leaving the lens behind in a hotel trash basket. The lens was badly scratched, so Prof. Langley sent it to the lens-maker Alvan Clark to re-polish, and it wound up better than before. Clark’s name was added to the now “Fitz-Clark Refractor” in gratitude.

To this day, the identity of the lens thief remains unknown. Since the entire affair is so shrouded in mystery, the belief is that Prof. Langley knew the person that stole the lens and that it’s “safe” return was conditioned so that the thief would remain anonymous.  It is of course debatable whether leaving the lens in a trash basket is considered safe, but at least it was recovered in the end.

With the size of modern day telescopes, such things are unlikely to happen again, although it would have a certain entertainment value to see someone trying to sneak away with one of the 1.8m wide mirror segments from the Keck telescopes, or one of the 8m primary mirrors from the VLT. But one would certainly have to go to somewhat more elaborate schemes than just walking in and removing it, if one wants to pull such things off today.

The world’s largest bug zapper

The 305m diameter radio dish of the Arecibo Observatory in Puerto Rico. Photo credit: NAIC

The 305m diameter radio dish of the Arecibo Observatory in Puerto Rico. Photo credit: NAIC

There are big telescopes, and then there are the truly humongous telescopes, like some of the radio telescopes. These bad boys are so big that the largest of them takes up an entire valley. This is the well-known Arecibo Observatory in Puerto Rico, that a lot of people likely know from Golden Eye, X-files or Contact, to name a few times it has been used in popular culture.

The observatories are, of course, mainly used to do astronomical observations, and not as fancy movie sets. The planetary radar transmitter here, and at the Goldstone Deep Space Network site in California are used extensively to observe asteroids, the terrestrial planets, and the larger satellites of Jupiter and Saturn.  To do this, they run hundreds of kilowatts of UHF signal out through each telescope.  By the time the beam is distributed across the many thousands of square meters of the primary telescope reflector, it’s diluted to the point that it doesn’t pose a hazard to anything.  However, along the beam path from the transmitter feed to the tertiary and then to the secondary reflectors, it is significantly more concentrated. This means that every now and then, the telescopes turn into something very different from instruments for peacefully observing the Universe.

The Gregorian dome of the Arecibo Observatory. Photo credit: NAIC

The Gregorian dome of the Arecibo Observatory. Finding your way out is not as easy as it seems. Photo credit: NAIC

At Arecibo, the transmitters, receivers, tertiary, and secondary are all contained inside a Gregorian dome. Birds tend to fly in and get confused about how to exit again. As interesting as it may be to inspect the inside of the world’s largest radio telescope, this is not without risk! If the birds happen to be between the transmitter and the tertiary reflector when the transmitter goes on, they are very rapidly microwaved. The birds’ remains may then land on the tertiary, where they get cooked into char. They can be removed from the tertiary’s surface from the access platform by using sophisticated tools, like a large wad of sticky tape on the end of a stick.

At Goldstone, birds can fly out of the beam line more easily, since the transmitter is not contained within a dome. But on one occasion, a swarm of bees were in the beam when the radar started transmitting. The telescope briefly acted as the world’s most expensive bug zapper. The resulting cloud of steam and fried bees caused a dramatic back-reflection of the beam until it dispersed.

There are no reports (yet) of larger things being fried by any of these instruments, and, admittedly, it would take quite some work to get anything without wings to be in the right place. But you could host a rather impressive and efficient BBQ party there. Just be mindful of  where you are, once the beam goes off. We don’t want any accidents!

Thanks to Michael Busch for providing this anecdote.

One of the Goldstone Deep Space Network Antennas. Photo courtesy NASA/JPL-Caltech

One of the Goldstone Deep Space Network Antennas. Photo courtesy NASA/JPL-Caltech

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.

The telescope that ran over a car

It is well known that cars are often involved in accidents, either by crashing into something, running over things, slipping off the roads and similar nasty business. This is also true in astronomy, where accidents do happen from time to time. What is different though, is that while cars can run into things almost everywhere, having something running over your car is a much rarer experience.

The Nordic Optical Telescope. Photo credit: NOT, Thomas Mellergaard Amby.

The Nordic Optical Telescope. Photo credit: NOT, Thomas Mellergaard Amby.

Meet the Nordic Optical Telescope (NOT): A nice, 2.5m telescope of a somewhat peculiar design. Whereas all telescopes have some sort of turning dome, that allows the telescope to point to many different parts of the sky, the NOT is constructed in such a way that not only the dome, but the entire telescope building turns, when you want to aim your telescope at a different patch of sky. This of course involved some engineering challenges, like, plumbing (there’s no bathroom in the telescope), as well as an entry staircase that is attached to the telescope. Which, amongst other things, means that you never really know what direction you are facing when you leave the telescope.

One day, the day-time crew were in need of hoisting equipment into the telescope dome, from the observatory pickup. For the crane to be able to reach the equipment, it needs to be positioned right at the wall of the telescope building. Thus, the pick-up was backed up, really close to the telescope, to make it easier to get the equipment in. This being an everyday operation, the crew unloaded the pickup, closed the dome, and proceeded with whatever they were doing.

The one warning sign you do want to pay attention to.

The one warning sign you do want to pay attention to.

Shortly after, someone decided that the telescope should be put in the parking position, so it was ready for the night to come. A sensible thing to do, except that no one had checked if the pickup had been moved away from the building. Thus, as the building turned, the entry staircase rammed into the side of the pickup, with the telescope effectively running over the car. Fortunately, the impact cut the wires to the safety system, which happened to run along the staircase, forcing the telescope to an emergency stop. Had this not happened, the telescope building could have been severely damaged, and the pickup as well.

The damages were luckily so small that the pickup could drive out of there, and at the time of writing, is still being used at the telescope. This is also one of the times where it really pays off to pay attention to the warning sign outside the telescope building.