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Observing Report: Mt Wilson!

August 22, 2009
1 - LA from Mt Wilson 1200

The LA Basin from Mt Wilson. The yuckiness is partly fog, partly smoke from forest fires, and partly the exhaust of a few million automobiles.

Looking toward the ocean at sunset. The fog helped suppress light pollution from LA while we were observing.

Looking toward the ocean at sunset. The fog helped suppress light pollution from LA while we were observing.

The antenna forest outside the observatory entrance. The top of the solar telescope tower is visible in the distance on the left.

The antenna forest outside the observatory entrance. The top of the solar telescope tower is visible in the distance on the left.

The immense dome of the 100-inch Hooker telescope looms through the trees like a mountain.

The immense dome of the 100-inch Hooker telescope looms through the trees like a mountain. Edwin Hubble used this scope to discover the redshift of distant galaxies and the expansion of the universe.

A closer look at the solar telescope, which was the first operational telescope on Mt Wilson. Hale used this scope to discover the Sun's magnetic field.

A closer look at the solar telescope, which was the first operational telescope on Mt Wilson. Hale used this scope to discover the Sun’s magnetic field.

We started observing with the Mt Wilson 60-inch at about 8:15 PM Wednesday evening. We aimed at Arcturus first, just to make sure that everything was in good working order. Then we split a nearby double star, Epsilon Bootes. After that we got started in earnest. Our first deep sky object (DSO) was M13, the great globular cluster in Hercules. This vast sphere of several hundred thousand stars was discovered by Edmund Halley in 1714. It has special significance for me because it was the first object I observed through the Great Lick Refractor on September 15, 2007, on the night that my lifelong interest in astronomy finally caught fire. In the 60-inch telescope M13 filled the field of view. It almost exhausted the eye, there was so much to  look at.

Here we go--the dome of the 60-inch telescope.

Here we go–the dome of the 60-inch telescope.

Then we went outside at about 9:20 to watch an Iridium flare–the sudden brightening of a giant solar panel on one of the Iridium communications satellites. It was the first time I’d seen one, and it was pretty cool.

Finally, the big gun itself. When you're in the dome, it's about all you can look at.

Finally, the big gun itself. When you’re in the dome, it’s about all you can look at.

Then it was back inside for more telescopic goodness. Post-flare we looked at NGC 6543, the Cat’s Eye Nebula. This is another summer to early autumn classic, and another object that I first viewed through the Lick Refractor almost two years ago. It was even better in the 60 inch telescope, a visibly S-shaped swirl of green with hints of structure  around the central star.

Arf--dunno how this caught me without a smile. I had one plastered on for the entire evening.

Arf–dunno how this caught me without a smile. I had one plastered on for the entire evening.

Then it was on to Jupiter, which was huge. The visible Galilean moons were not just points of light in the eyepiece but little spheres; they looked like the worlds that they are. An odd side effect of looking through the giant telescope was to make us appreciate our own scopes more. For picking out detail on nearby objects like Jupiter, atmospheric turbulence is often more limiting than telescope optics. I’m not going to lie and claim that the views in my 6-inch telescope are as good as the views through the Mt. Wilson 60-inch–but on Jupiter I reckon that the 60-inch scope delivered twice as much detail as my scope, rather than the ten times more detail that optical theory would suggest. If the 60-inch was up on Mauna Kea and not plagued by light pollution, smog, and turbulence, it would perform a lot better–as would any telescope. I’m not complaining. Just observing that although our backyard scopes don’t show nearly as much as big observatory scopes, they still show quite a bit.

When the big scope is pointed straight up you can sit in a chair to observe, but most of the time we were up and down the ladder to reach the eyepiece.

When the big scope is pointed straight up you can sit in a chair to observe, but most of the time we were up and down the ladder to reach the eyepiece.

There was another way in which the views Wednesday night made me appreciate my own telescopes more. Galileo discovered the moons of Jupiter, and he never saw them through a telescope with a diameter of more than an inch. The finderscope that I use on my airline-portable travel telescope has a bigger aperture and sharper optics. And yet Galileo changed the world with the observations he made through his tiny, optically terrible telescope. To get to see the Galilean moons as little worlds in the 60-inch reinforced how ridiculously fortunate all of us are to have such nice tools available.

When you go downstairs from the observing deck to use the restroom, you go past a bank of lockers. The names include Zwicky and Minkowski. This one belonged to Edwin Hubble.

When you go downstairs from the observing deck to use the restroom, you go past a bank of lockers. The names include Zwicky and Minkowski. This one belonged to Edwin Hubble.

Speaking of tools, we got to take turns photographing Jupiter through the eyepiece. As is often the case, I got my best picture in the first few snaps. I was so busy previewing my pictures and talking with the other visitors that I completely missed the next object, planetary nebula NGC 7662, the Blue Snowball. Many thanks to Tom Mason, our scope driver, for sharing the photo below.

Planetary nebula NGC 7662, the Blue Snowball. It consists of vast rings of gas blown off by a dying star. Our sun may look like this in about 5 billion years.

Planetary nebula NGC 7662, the Blue Snowball. It consists of vast rings of gas blown off by a dying star. Our sun may look like this in about 5 billion years. This photo is by Tom Mason, our scope driver for the evening.

Faint DSOs require light-gathering ability primarily and not the resolution of fine details. The 60-inch totally blew away any backyard scope on planetary nebulas. After the Blue Snowball we checked out another, even more famous planetary nebula, the Ring Nebula or M57. In backyard scopes it looks like a perfect little doughnut of gray smoke. In the 60-inch it was a huge and green, with threads of gas and dust visible in the middle. I could even make out the central star, which is a legendarily tough object to detect visually.

After the Ring we went back to Jupiter, and then on to Neptune, which is currently close by Jupiter in the sky, just as it was for Galileo four centuries ago. Neptune is incredibly distant, 4.5 billion kilometers away. That’s 30 times farther from the sun that we are, and 6 times farther away than even Jupiter. Even in the 60-inch Neptune was small, but it was visibly a sphere, which is quite an achievement for any Earth-bound optical telescope. Coming down the ladder, I had to remind myself that Neptune is now the most distant planet in the solar system, since Pluto was (correctly, IMHO) demoted to dwarf-planethood.

The final object I observed through the big gun was the Saturn Nebula, NGC 7009, another planetary. It looked much like its namesake. Click on the link above, get 10 feet back from your computer, and you’ll have a pretty good idea of what I saw through the 60-inch.

The highlight of the evening for me: Jupiter and its moons. Three of the four Galilean moons were visible in the eyepiece, but this photo only shows one: Io, on the upper right.

The highlight of the evening for me: Jupiter and its moons. Three of the four Galilean moons were visible in the eyepiece, but this photo only shows one: Io, on the upper right.

By the time I’d gotten down the ladder from looking at the Saturn Nebula, it was 3:00 AM and time for me to skidaddle; I had to teach Thursday morning and that meant getting at least a little sleep. On the way out, though, I did stop long enough to enjoy a view of the newly-risen Pleiades in my binoculars. You can do the same if you’re willing to get up in the middle of the night–or you can look forward to a Pleiades mission here in a few months. It all comes back around.

Lots of things came back around for me Wednesday night. M13 and the Cat’s Eye ushered me into astronomy, and it was great to revisit them with two years of knowledge and experience under my belt–as well as 24 more inches of aperture.

What I wanted most from the evening, though, was to photograph Jupiter and its moons. They were the first things I ever viewed through a telescope, in my high school astronomy class. They were also among the first things that Galileo observed with his telescope, 400 years ago this December. I wish he could see how far we’ve come–and how much we owe him.

Finally, a huge thank you to the Pomona Valley Amateur Astronomers for inviting me along and being such gracious and interesting hosts. I had the time of my life. If you ever get the chance, go.

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10 comments

  1. I really enjoyed your writeup and pictures of our trip to Mt Wilson last week – so glad you were able to join us. I love the shot of the telescope against the purple sky!


  2. […] Fire, which has burned more than 100,000 acres and shows up quite nicely from space, is approaching Mt Wilson and firefighters on the ground had been pulled out; the fire will be fought from the air from here […]


  3. […] you’re trying to see. The less atmosphere you have to look through, the better, which is why observatory telescopes are on mountaintops, and why seasoned stargazers try to catch their targets as far from the horizon […]


  4. […] had a look at the Cat’s Eye Nebula, and while it didn’t look as good as it did in the 60-inch at Mt. Wilson, it still looked awfully nice.  The spiral structure was obvious, it was a gorgeous flourescent […]


  5. […] up into the mountains here to take advantage of the darker skies. I got to spend an evening with the 60-inch telescope on Mt. Wilson, which is probably the biggest telescope open to visual use by amateurs. At last I got a decent […]


  6. […] About a dozen of us from the Pomona Valley Amateur Astronomers spent Saturday night observing with the 60-inch telescope up on Mount Wilson. A really excellent night on the mountain is a Goldilocks affair–you need enough of a marine layer to cover up the lights of LA, but the fog has to stay low enough not to swamp the observatory itself. The PVAA visited Mount Wilson last summer, but got fogged out. That worked out okay for me, because they rescheduled for the fall and I found out about the trip in time to go along. […]


  7. […] Astronomy Stargazing for people who think they don't have time for stargazing. « Observing Report: Mt Wilson! Extended Mission: Follow the Moon » Observing Report: Lehi, Utah; or, When Binoculars […]


  8. […] a big role in the history of astronomy, it also played a big role in my history in astronomy (see this and this). So I was happy to get one of the last models of the grand machine made by miniature […]


  9. […] the famous 60-inch reflector on Mount Wilson (which I’ve been fortunate to visit – see here and here). Here’s the light path of the NST (an unmodified version of this image is at the […]


  10. […] I’d been up there – my only other trips up were in 2009 and 2010 (observing reports here and here). So it was very satisfying to be back. It is amazing to look back and realize that in 2010 […]



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