Return to Old Town Sidewalk Astronomers
Observing Through 60 Inches
Jane Houston Jones
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The base of the 60-inch. At left is the focuser and eyepiece position for the cassegrain focus.
One of many 1917-era electrical control panels. This one to control the dome motors.
Operators position for the 60-inch.
Intrepid observers from the Saturday night session -- Sidewalk Astronomers and visitors from San Diego.
Nothing prepares you properly for your first look at or through a big telescope. We drove to Pasadena and up into the San Gabriel mountains during the January 2002 new moon weekend. Our destination was the historic 60-inch telescope at Mount Wilson. Our hosts for the weekend were the Los Angeles Sidewalk Astronomers, who usually set up their homemade reflectors outside the dome for public star parties.
This weekend they arrived without telescopes, and spent Friday and Saturday night peering through the eyepiece of the 60-inch telescope instead. I could write an entire article about the the history of Mount Wilson, the mirrors and telescopes, the current research using adaptive optics with the 100-inch Hooker telescope, but you can read that yourselves if you are interested. Here is the website for Mt. Wilson Observatory and the Mount Wilson Observatory Association http://www.mtwilson.edu/General/ for your telescope and history fix.
Before dark, I made sure to walk by the famous storage lockers. One square foot in size each, a wall of three rows of four lockers bore the names of some of the famous Mount Wilson astronomers: Minkowski, Zwicky and Hubble, to name but a few. An old phone list on the bulletin board lists Halton "Chip" Arp, next to one of the many black rotary telephones.
The telescope operator and Mount Wilson Observatory Association docents have a list of target objects that show well in the 60-inch f/16 telescope. And in-between objects they tell tales, give telescope and observatory history, and answer any questions you may have. The upper cage had been removed and the telescope was in its cassegrain configuration for the star party.
With a group of 25 people, it takes about an hour for everyone to view one object. As with most group star parties, many of the participants seemed to poop out by midnight or so, which meant they had only looked at about 5 objects. After midnight, with a smaller crowd, we were able to move through objects more quickly, and for those of us who stayed until 5:00 a.m. that meant we got plenty of observing time. The conditions on the two nights at latitude 118 degrees 3.6 minutes west, longitude 34 degrees 13.0 minutes north were not too bad. The sky brightness at Mount Wilson from Los Angeles is approximately equal to the sky brightness from the full moon, and the seeing ranged from good to poor. Even so, we had some spectacular views of some amazing objects.
Our first observation on the first night was the blue and yellow double star, iota Triangulum. Next was Saturn, with six moons (even Mimas) visible and a large brown oval storm on the north equatorial band. The storm was as big or bigger than the red spot of Jupiter. And speaking of that other big planet, Jupiter's red spot was near the central meridian too early for observing on the first night, but we went back to it the second night at about 1:00 a.m. and got a real treat! The red spot hollow sported a black dot of moon shadow near where a tear duct would appear on a drawing of an eye. Right next to the shadow of the moon, I saw the round beige disk of Europa. The red spot itself was nearly invisible, a washed out faint pink oval. All belts and zones, including the faint equatorial band were visible. The four of us who were sketching were busy getting looks at the planets, and then comparing drawings.
Other highlights (for me, at least) were IC418 in Lepus (the red planetary), Eskimo NGC2392 in Gemini, and Ghost of Jupiter NGC3242 in Hydra at about 800 power. It looked like a Hubble Photo! The trapezium and surrounding nebula in M42 was spectacular. I was able to see the G star inside the trapezium, and the telescope operator told me it is not unusual on a sub arc-second night to see a dozen stars inside the trapezium through this telescope! He also told me that spring and summer are the best observing months, with steady air, and that January is pretty dismal. NGC3115 needle galaxy in Sextans was one of the few high-surface brightness galaxies we attempted to view, the other being the Sombrero Galaxy, M104, in Corvus.
But the absolute highlight for me was to clearly see the jet in M-87. It looked like blobs of material, a string of clumpy clusters, forming a pipe of hydrogen blowing off the elliptical galaxy and pointing at 9:30 in our eyepiece view at 220 and 440 power. The x-ray images we see of this object do not do justice to the visual observations. All pictures I have ever seen of the jet show the galaxy overexposed as a bright oval with no detail and the jet appears outside the oval, almost like a nearby companion cluster or small galaxy. The 60 inches of light gathering power, and the 50 mm eyepiece view for 440 power, showed the jet forming within the galaxy itself. It was worth the trip to the southland just to see this object with my own eyes!
Speaking of quasars, we also observed magnitude 17 Q957 +561 A and B, the variable double quasar in Ursa Major. This "double" quasar is the first example found that demonstrates Einstein's prediction of gravitational lensing. This is a single quasar that has two nearly identical images caused by the gravitational effect of an (unseen) intervening galaxy. Here's a picture of the quasar and the galaxy, compliments of the Hubble Space Telescope. http://www.astr.ua.edu/keel/agn/q0957.html
We also observed our nearest quasar, only 2 billion light-years away, magnitude 12.8 3C273 in Virgo. The strange name "3C273" comes from a radio survey that detected many strong radio sources in the sky such as this quasar. Not only do these objects emit prodigous amounts of energy (more than 100 times an ordinary galaxy), they also change in brightness on very small timescales.
At midnight on our first night, we walked over to the 100-inch Hooker telescope, and got to stand outside on the catwalk as the dome rotated. We got a cook's tour (thanks to a friend who is the telescope operator on the 100-inch adaptive optics system), and then went into the control room, the shop, saw where the 100-inch gets bathed and realuminized, and then, back to the 9-inch thick, 1900-pound 60-inch mirror, for more peeks into the past.
A night on Mount Wilson isn't your typical star party, and although a deep sky observer may get antsy waiting for a telescope operator to cycle through the crowd to the next object, it was a deeply satisfying new moon observing weekend. I wonder what Mr. Hubble stored in his locker on those observing nights long ago?
Copyright © 2002 Jane Houston Jones