Robo-AO Comes to Palomar

Robo-AO, a new laser-guide star adaptive optics system for Palomar's 60-inch telescope, had a successful test of their laser last weekend.

False-color composite image of the Robo-AO laser & 60-inch telescope

Adaptive optics is a technique that allows ground-based telescopes to remove the blurring affects caused by Earth's atmosphere. The adaptive optics system uses a star as a calibration source and then deforms a small mirror to correct for distortions caused by the atmosphere. The corrections are made faster than the atmosphere can change -- often thousands of times per second.

By projecting a laser into the sky astronomers can expand this technique to cover a larger fraction of the sky.

Here is the 60-inch telescope last Sunday night just after the dome was opened.

The 12-Watt laser is in the black box mounted on the south side of the telescope (between the arms of the mount).

Here is the view with the lights turned off and the laser turned on:

Notice that you can't see the laser (but you can see where it is making a part of the telescope's insulation fluoresce!). Being invisible is one of the chief advantages for the laser.

The light that the laser emits is invisible ultraviolet light. Because you can't see the laser light this system requires no human spotters to be staged outside looking for air planes. All laser-guide star systems (like the one that has been used on the 200-inch Hale Telescope) that make use of visible light are required by the FAA to have spotters. Even hand-held laser pointers can be a danger to aircraft.

The Robo-AO system does not require spotters, which is perfect because the telescope normally operates in robotic mode without any people being present.

As the UV laser shines up toward its astronomical target astronomers make use of something known as Rayleigh scattering. The UV light scatters off of molecules in the air, giving a return signal that tells the deformable mirror in the adaptive optics system how to correct for atmospheric turbulence.

The Robo-AO system will be the first robotic laser-guide star adaptive optics system, delivering high-angular-resolution observing in the visible for up to hundreds of targets per night. This will enable the exploration of science parameter spaces inaccessible to large diameter telescope adaptive optics systems. A fully-working testbed has been operating at Caltech in the Cahill Center for Astronomy and Astrophysics basement for several months, and the system is expected to start its science demonstration period in early 2011 at Palomar Observatory's 60-inch telescope.

From there the Robo-AO system will be available as a relatively affordable and portable option for to 1-3 meter class telescopes around the world.

The Robo-AO project is a collaboration between Caltech Optical Observatories and the Inter-University Centre for Astronomy and Astrophysics and is partially funded by the National Science Foundation.

Palomar History Photo of the Week - September 27, 2010

Here is the 200-inch disc in the optical shot at Caltech on January 3, 1938*. That is a 104-inch grinding tool sitting on the huge Pyrex disc.

In this view from the side you can see through the edge of the glass and make out the honeycombed structure that forms the underside of the disc.

Thanks go out to Nancy who has been helping with our scanning of this and other vintage Palomar images!

*Curiously enough the next photo in this archive shows an optician working on a smaller piece of optics. On the wall behind him is a 1939 calendar, so it may be that the image above has an incorrect date.

Minotaur Launch

Check out this photo of last night's Minotaur IV launch:


It was a beautiful display that was captured nicely with this 119-second exposure photo taken by Mark Lane from the parking lot of the Palomar 60-inch telescope. The launch was the perfect end to a Friends of Palomar Observatory event that took place last evening.

Click to embiggen and you should notice that Mark's photo nicely captured the two staging events of the launch. The rocket was launched from Vandenberg Air Force Base.

If you are interested in seeing events like this in the future, be sure to check out the updates that are posted at spaceflightnow.com.

Astrophoto Friday - The UFO Galaxy

As of their last web update the Palomar Transient Factory (PTF) has so far discovered 752 supernovae. The heart of the PTF survey is Palomar's 48-inch Samuel Oschin Telescope - a wide-field Schmidt camera. It operates in robotic mode, taking a new image of the night sky every 90 seconds.

Most of the time the images are optimized to hunt for supernovae and are not cleaned up to make them visually appealing. Thankfully some of the PTF team has taken the time to produce some nice shots, which I will be sharing here from time to time. Our first one is of a galaxy known as NGC 2683.


NGC 2683 is a nearly edge-on spiral galaxy located some 16 million light years away in the direction of constellation Lynx. NGC 2683 is nicknamed the UFO Galaxy.

Palomar All-Sky Movie: Sept 10 - 14, 2010

Here is a short video covering ~116 hours of night and day from the new Palomar Observatory all-sky camera:

Here is a direct link to the video on YouTube.

Notice at night in the upper and lower right it never gets completely dark. This is light pollution, aka sky glow, from city lights.

As you can see in the daytime, the sun completely saturates the camera's CCD detector causing it to heavily bleed out on to other parts of the image. In spite of this, the camera is still a good daytime cloud detector (when we have clouds).

The camera is not yet up for the public, but that will be coming soon.

Giant Owls from Space Invade Palomar?

It only took about 5 days for an owl to decide that our new AllOwl-Sky Camera makes for a pretty good perch. Sigh.

The photo above is a 151 second exposure taken the night of the 14th. The owl didn't even have the good graces to hold still during the exposure so there are multiple images of the talons.

It seems that Palomar is not the first to have this kind of problem. Unfortunately our owl has been back and left "calling cards" on the glass dome of the camera. We need to both clean the lens and discourage the owl from perching there (or give it a place that is even better). Does anybody have any good ideas about that?

Look tomorrow for a short video of from the all-sky covering about 4 nights & days taken before the owl came to visit.

Palomar History Photo of the Week - September 20, 2010

This week's history photo of the week shows two members of the crew at Westinghouse posed inside a section of the mammoth horseshoe of the 200-inch Telescope.

I have always hoped that this was just a publicity shot, because at this point in the process of manufacturing, how much is a tape measure going tell you about the job that you have done?

Feeling Blue from Light Pollution

There are a lot of changes coming in the world of street lighting that could have a major impact on operations at Palomar Observatory. For a short perspective on it have a look at this recent article in the San Diego Union Tribune newspaper.

In summary there is a big push to convert away from the astronomy-friendly low-pressure sodium lighting installed to help protect Palomar Observatory in favor of full-spectrum lights. These full spectrum lights are rich in blue light which disproportionately brighten the night sky. While the lights will be dimmer and thus save energy, their impact on astronomical research will be felt.

The International Dark-sky Association has come out against such changes. You can read their research paper Visibility, Environmental, and Astronomical Issues Associated with Blue-Rich White Outdoor Lighting here. A shorter, summary piece Seeing Blue is here.

While these are big issues for cities and organizations to sort out don't forget that you can make a difference right at your own home. By choosing to turn off unneeded lights or installing a dark-sky friendly light fixture you can improve the sky for everyone in your area. If your area happens to be San Diego County, don't forget that thanks to SDG&E Dixieline Hardware now has a great deal on lights that are dark-sky friendly.

Astronomy Events in So Cal

If you are looking for something astronomical to do this weekend, look no farther than the Pacific Astronomy and Telescope Show in Pasadena. It should be two awesome days of astronomy-related goodness.


If two days of astronomy isn't enough for you, why not consider signing up for a short course on astronomy where you can learn to Think Like an Astronomer? It is only $40 and you get a telescope out of the deal. The details are below:

Palomar History Photo of the Week - September 14, 2010

Our history photo of the week shows the 200-inch mirror as it looked in the Caltech Optical Shop May 13, 1939. The disc looks dramatically different from how it looked when it arrived three years earlier.

Last Night from our New All-Sky Camera

Here is how last night looked from our new all-sky camera:

If you look closely (you may need to watch it more than once) you can spot the dome of the Hale Telescope in the upper right - near the edge of trees. Here is a direct link to it on YouTube.

Palomar History Photo of the Week - Labor Day 2010

It is Labor Day here in the U.S. - time to celebrate hard work by hopefully taking a day off from work. A lot of people worked very hard building the 200-inch telescope including these people from the Westinghouse Electric and Manufacturing Company's South Philadelphia plant.


Westinghouse assembled this cast photo of the crew that built the telescope. In this shot they are assembled in the still ring that would later attach the 200-inch mirror to the telescope. We are thankful for the hard work put in by all of the people who helped make the observatory a reality.

Happy Labor Day!

Fire Danger now Very High

As of this morning the Fire Danger in the Cleveland National Forest on Palomar Mountain is now rated at "Very High". Be careful out there.

Hale Telescope Tours Continue on Weekends in September & October

Most of the time when people visit Palomar Observatory they can only see the Hale Telescope from the Visitors Gallery (shown above). If you visit on a weekend through the end of October you can get on the other side for a guided tour.

Tours are offered at 11:30 a.m., 1:00 p.m. & 2:30 p.m. Tickets are $8.00 per person for all ages. Tour tickets are sold in the gift shop the day of the tour on a first-come, first-served basis. The gift shop opens at 10:00 a.m. No prior reservations are taken. The tour is not recommended for children under six years of age. Sorry, no pets.

Tours cover the history and current scientific research of the Palomar Observatory, with a special emphasis on the 200-inch Hale Telescope. Remember it can be pretty cool in the dome as the interior is kept at nighttime temperatures (for an elevation of 5,500 feet). High-heeled shoes are not recommended for the tours.

These one-hour-long tours are held on Saturdays & Sundays only now through the end of October.

Preview: Palomar's New All-Sky Camera

Here is a preview shot from Palomar Observatory's new all-sky camera. This photo was taken last night right at moonrise. Our all-sky camera is not yet perfectly focused or installed in its final spot (It will be on the pole in the photo), but in this shot it did capture the Milky Way and a meteor.


I will announce it here when the camera is up and running. From time to time I'll post interesting images or movies as they come in.