Wednesday, April 30, 2008

April Skies

The month of April is nearly done. What have astronomers been looking at with the 200-inch this month? Lots of stuff (as always). Here's a sampling of what they have been studying with the Hale Telescope this month:

Active galactic nuclei
Dust-obscured quasars
Quasar triplets
Optical Transients
Radio Transients
Dust-obscured galaxies
Starburst galaxies
Dwarf galaxies
"A" stars
Cataclysmic variable stars
Intergalactic Medium
Near-Earth asteroids (as they were radar mapped at Goldstone)

Depending on the requirements of the astronomer, the telescope was set up so that observations could be performed with visible light and/or near infrared cameras and/or spectrographs. Our spectrographs and adaptive optics instruments are large enough that they ride in the Cassegrain cage at the bottom of the telescope while our other instruments are up in prime focus.

A few nights were cut short by high humidity, but we lost just two nights due to weather, which isn't bad for April. 2 nights were devoted to engineering on particular instruments.

As is normal, most observers work from sunset to sunrise. The astronomer and the telescope operator work from a warm room. Images are viewed there and analyzed in greater detail after the observing run has been completed. Most astronomers spend much more time pouring over their data than they do in collecting it.

Saturday, April 26, 2008

Back Home Again

Earlier this week I posted about a virtual model of the Hale Telescope. Let me now tell you about a real model.

When I started here there was an old model of the 200-inch telescope & its dome that had fallen on hard times. Look at the 2 pictures below and you'll see what I mean.




The dome was broken in numerous places, part of the inside catwalk had also broken, paint was missing here and the. The entire thing was covered in sawdust.

There are lots of models of the 200-inch telescope in the world, so it would be possible to find or even make another. But this model was built by Russell W. Porter in 1936.

Russell Porter as you may know had a huge role here at Palomar in the early days. He led the surveying team and decided what domes went where. He also figured the optics on the 18" Schmidt, Palomar's first operational telescope. Perhaps Porter's most famous works are the series of detailed cut-away drawings that he did of the 200-inch telescope.

These engineering drawings were made from blue prints, often before the actual parts were assembled. They were detailed enough to show the workers how parts were to fit together. These drawings are magnificent works of art in their own right

Porter's cut-away style is evident in the model, which has been lovingly restored by Robert Kline of Design Dynamics. Bob brought it back last Saturday and I must admit to being overjoyed at seeing the fine work he did.



I think you'll agree that it looks vastly better than the broken-down version above.

Thursday, April 24, 2008

America's Next Top Modeler

Way back in December I posted (Your Own Virtual Hale Telescope) about how Selden Ball has created a wonderful Hale Telescope add-on for the free space simulator program known as Celestia. Selden is doing some mighty fine work and is paying close attention to detail. Finding the answers to some of his questions has taught me some things about the Big Eye.



He continues to work on this virtual Hale Telescope and has created his own blog to show off his progress. Be sure to check it out and you might like his Youtube video as well.

Tuesday, April 22, 2008

Into the West

Not much time to write today, but I have been meaning to post this photo for sometime now, so here it is:

This is the view looking into the west arm of the Hale Telescope. To put this into perspective see the next picture. To enter the west arm one needs to walk the gangplank into the hole in the photo below:



Inside the west arm is the slew motor that drives the telescope in declination (north or south). The original 1-Horse Power motor was replaced just a few weeks ago by the Palomar day crew. It will get a little bit of care and be used as a spare, should the new one not last 70 years or so like the first one did.

Saturday, April 19, 2008

Defending Your Right to See Starlight

A year ago I had the privilege to visit the beautiful island of La Palma to attend the Starlight Conference.


Can you pick me out in the crowd?

At the conference the Declaration in Defense of the Night Sky and the Right to Starlight was adopted by the international group of attendees. The basic idea behind it is that everyone should have the right to see and enjoy the night sky and that obtrusive light must be controlled. Why? It is a part of our heritage, nature depends on a 24-hour day/night cycle, our health may depend on it, and of course it is good for astronomy too.

Tomorrow, April 20th has been declared The World Night in Defence of the Starlight. Be sure to visit the link, watch the videos and act to preserve the night sky for everyone.

Saturday, April 12, 2008

Flying Electric Trousers

Yes, Flying Electric Trousers. Years ago astronomers actually rode inside the Hale Telescope all night long. They would sit at the top end of the telescope in what is called Prime Focus. They would be up there to make sure the pointing and tracking were accurate, focus the camera, and physically pull the shutter to start exposing the image.

We have a nice look back at those from the late Jesse Greenstein. He gives two quotes that put things into perspective:

"Working at night in the small cage high above the primary mirror, feeling closer to the stars than the earth, remains an exhilarating and unforgettable experience."

and

"You also had to have a tough bladder because, if possible, if it was a good night, you stayed up from seven o'clock to five. That's ten hours!"

Imagine working high inside the telescope, by yourself, in the dark, for the entire night. Nights on Palomar can be cold, especially in the winter time. That's where the Flying Electric Trousers come into the story.

The trousers and shirt were used to keep the astronomers warm during the night. They were surplus F3-A electrically heated flying suits used by the U.S. Army Air Force during World War II.

Recently a cache of these old suits was uncovered at Palomar. One of the suits is now on display for the observatory's many visitors to see. If you are in the area, come and have a look. The suit on display belonged to Horace W. Babcock, Palomar's director from 1964 - 1978.

A few years ago Jean Mueller, telescope operator (aka Night Assistant) on the 200" managed to save one of the manuals for the old F3-A suits. It is fragile, but it has now been scanned. Here is the cover:

I can post all of the F3-A manual if people are interested in seeing it.

By the way, modern astronomers make use of the Hale Telescope from the comfort of a warm room. A large digital camera rides in Prime Focus. The room features computers for controlling the telescope & cameras, a stereo, coffee, a bathroom and heat. For our smaller telescopes the astronomers do not even need to come to Palomar. They can be operated remotely from the comfort of an office, kitchen or elsewhere.

Thursday, April 10, 2008

Time to Get to Work

I mentioned the epic journey of the 200-inch mirror's trip across the country in my Trainspotting post. Seventy two years ago today, April 10, 1936, the train carrying the giant Pyrex mirror finally pulled into its destination: Caltech in Pasadena, CA.


Under the direction of Marcus Brown, the real work on the glass-grinding and polishing the mirror into a parabola, was set to begin in the Caltech optical shop.

No one knew that the task, with delays for World War II, would span 11 and a half years. In the process some five and a half tons of glass were removed.

I'll have more on Marcus Brown and the figuring of the mirror in a future post.

Saturday, April 5, 2008

Clearing the Air

Ground-based telescopes are entering into a new era with adaptive optics (AO) technology providing sharper views of the universe than ever before. AO allows astronomers to remove the blurring effects of Earth's atmosphere in real time.

The adaptive optics program at Palomar is more than a decade old. In October 2004 we added a new dimension to the program and achieved first light with the laser-guide star (LGS) system. LGS allows astronomers to create an artificial star and use AO in a much larger fraction of the sky.

To do this they shine a narrow sodium laser beam up through the atmosphere. At an altitude of about 60 miles the laser makes a small amount of sodium gas glow. The reflected glow from the glowing gas serves as the artificial guide star for the AO system. The laser beam is too faint to be seen except by observers very close to the telescope, and the guide star it creates is even fainter. It can't be seen with the unaided eye, yet it is bright enough to allow astronomers to make their AO corrections.



The technology is involved. Early on all the time devoted to it is what we call engineering time. Basically that is time on the telescope to tinker, measure and improve all in the name of getting ready for the real astronomical observations that are to follow.

Following that is what is known as shared-risk science. During this time astronomers come to use the LGS system to do real astronomical observations, but with the knowledge that there will still be some time devoted to engineering mixed into the night.

One year ago today was the first night of shared-risk science with Palomar Observatory's laser-guide star adaptive optics program. Caltech professor Lynne Hillenbrand and graduate student Adam Kraus where here to use laser and natural guide Star adaptive optics to conduct a high-resolution imaging survey of young low-mass stars and brown dwarfs in several nearby young associations.

JPL astronomer Patrick Lowrance was back later in the month for another LGS night to study L, T, and brown dwarfs. The time-lapse movie below shows approximately 3 hours of LGS operations during a night as photographed from outside the Hale Telescope dome.






video

Each frame in the silent movie was a 30-second exposure. Along with the laser, stars and airplanes are visible in the sky.

More photos, movies and information is available on the Palomar Observatory Adaptive Optics page.

Friday, April 4, 2008

Astronomical Bandwidth

Palomar Observatory just upgraded its data transfer rate from 45 megabits per second to 155Mbps! Data and commands shoot to and from Palomar Mountain via the High Performance Wireless Research and Education Network (HPWREN) enabling new forms of astronomical research that were not possible before.

Studies at Palomar of gamma-ray bursts, near-Earth asteroids, supernovae, Kuiper Belt objects and more have been growing with the use of automated telescopes, armed with big cameras, that have put increased demands on the network. By collaborating with HPWREN and other partners the observatory now has in place what might be the fastest remote astronomical observing capabilities in the universe. Well, maybe just the known universe.

For the full scoop, check out this story from HPWREN news.


Shown above is the crew from HPWREN and Palomar Observatory installing the new microwave antenna outside the dome of the 48-inch Samuel Oschin Telescope.

Wednesday, April 2, 2008

Touring the Big Eye

Two years ago yesterday marked the anniversary of the beginning our first program of Saturday tours for the general public. Now that it is April again it is time for the new season of tours to begin.

The tours are available every Saturday (and only on Saturdays) from April through October (except the occasional time when observatory operations may get in the way) at 11:30 a.m. & 1:30 p.m. Tickets are on sale in the Observatory Gift Shop on the day of the tour and are sold on a first-come, first-served basis. The tickets only cost $5 for adult (less for seniors and kids) and in my biased opinion are a fantastic deal.

The tour is a guided hour (often more) that leads up from the visitor center, into the dome for the 200-inch telescope, on to the observing floor and (weather permitting) out onto the outside catwalk. 2 or more docents lead the tour and explain the epic story of how the big telescope was built, how it is used now and what other kinds research is taking place at Palomar.

Visitor response has been overwhelmingly positive with rave reviews and almost all tours selling out. If you get the chance, come join us on a tour.