365DaysDate: February 26, 2009


Title: Palomar Sky Surveys on Your Desktop

Podcaster: Scott Kardel

Organization: Palomar Observatory / Caltech

Description: The Palomar Observatory has had a long tradition of performing sky surveys. Here’s a look at some old and new sky surveys that have been performed with the 48-inch Samuel Oschin Telescope at Palomar. The podcast will include resources on how to get some of the results on your computer’s desktop, how to see some beautiful images that have been produced from the surveys and some results that have produced findings that rocked the solar system.

Bio: Scott Kardel received his MS in Astronomy from the University of Arizona and his BS in Physical Science / Secondary Education from Northern Arizona University. For the last two and a half decades he has been working to bring an understanding of science and the universe to a wide range of audiences. In 2003 he became the Palomar Observatory’s first full-time person devoted to public outreach. There he works to bring Palomar’s rich history and story of exploration on the road and on the Net to a wide variety of groups throughout Southern California and beyond.

Today’s Sponsor: This episode of “365 Days of Astronomy” is sponsored by Miranda Richards in memory of her dad, Dennis Rolph. “I was only 4-1/2 at the time, but was lucky enough to be living in Idaho when there was a total eclipse of the sun thirty years ago (2/29/79), and I was lucky enough to have a dad who would inspire us to be amazed at the universe. The eclipse was just one of the first memories I have of his instillment of science into my life. We’d watch NOVA and Cosmos together. We’d take out the telescope and view the rings of Saturn and the Galilean moons of Jupiter. If you have children, please take the time to share the sky with them, even if it’s just laying on a hillside staring at Orion like we used to do. The wonder that astronomy evokes is something that lasts a lifetime. Thank you all for putting this project together!”


Welcome to another edition of the 365 Days of Astronomy podcasts. I am Scott Kardel of the Palomar Observatory.

I am standing inside the dome of Palomar’s 48-inch Samuel Oschin Telescope.  It is a wide-angle Schmidt telescope that was built for mapping the night sky.  It saw first light back in 1949 as astronomers used it to make the National Geographic Society-Palomar Observatory Sky Survey. The project formed the first detailed survey of the heavens, covering the entire northern sky and down to 33 degrees below the celestial equator.

The photos for the survey were shot on huge glass photographic plates measuring 14 inches on each side and capturing a field of sky six degrees wide.  Nearly two thousand photographs were taken with red sensitive and blue sensitive films.

Along the way numerous comets, asteroids, nebulae, star clusters and supernovae were discovered.

Caltech astronomer George Abell used the survey to form the first catalog of galaxy clusters and in the process discovered something about the large-scale structure of the universe. He found that clusters of galaxies were themselves organized into clusters of clusters. He also showed how the brightness of certain galaxies within a cluster could be used to determine the distance to the galaxy cluster, allowing astronomers to map the large-scale structure of the universe. Abell’s work served as one of the starting points for observational cosmology.

A second sky survey was performed here at Palomar with the Samuel Oschin Telescope from 1985 to 2000.  Like the first survey it used large glass photographic plates.  And, like the first survey it yielded many new discoveries.

Remember that the first survey was from before the digital era. Photographic copies of the plates were made astronomers at more than 100 institutions around the world. The second survey took place as the digital era and the Internet was just coming into existence.  As the plates were produced they were digitally scanned. Thankfully, now, anyone with access to the Internet can see the whole sky even if you live where light pollution or clouds dominate.

Thankfully, now, anyone with access to the Internet can see the whole sky.  These surveys and others are available for free.  Two of the easiest ways to access the sky from your computer would be to use Google Sky and Microsoft’s WorldWide Telescope.

Amateurs and professionals alike have also used the images from the sky surveys to do things like make finder charts or check a possible supernova discovery. Some people like Davide de Martin have used the digitized images from the sky surveys to produce beautiful images of the universe.  Look for his website at You’ll be glad you did.

Sky surveys here at Palomar Observatory have continued well into the digital era. The Palomar-QUEST survey began in 2003 and concluded in the fall of 2008.  Instead of big glass photographic plates astronomers used an array of digital imagers forming a 196-Megapixel camera.  The telescope was automated and the data was streamed away from Palomar via the High Performance Wireless Research and Education Network, a high-speed microwave network that allowed astronomers to control the telescope and receive the data without having to travel to the mountain.

Most people have not heard of this recent survey, but just about every person interested in astronomy has heard of one of the findings that came out from it.

Do you remember Pluto?  The discovery Eris, announced in 2005 by Caltech’s Mike Brown rocked the astronomical world – at least as far as the general public saw it.

Pluto sits out mostly beyond the orbit of Neptune in an icy swarm of bodies known as the Kuiper Belt. In the years just prior to the discovery of Eris, Pluto had this sort of dual citizenship as the ninth planet and the largest member of the Kuiper Belt. When Eris came along and it was confirmed as being bigger than Pluto the discussion became heated. Should it be classified as the 10th planet or should it and Pluto be just another member of the Kuiper Belt?  Back then Eris didn’t even have an official name because the rules for naming objects depends upon their classification.  At the time it bore the nickname “Xena” and its official name, 2002UB313, was nothing more than a catalog number.

The International Astronomical Union convened in 2006 to decide the fate of the solar system, or at least to hopefully give everyone a working definition of what a planet is.  What they ended up with was a new category for Pluto and other objects that are large enough to be round but do not make their definition of a planet.  This new category, that of “dwarf planet”, now includes five worlds: Pluto, Eris, Ceres-the largest of the asteroids, Makemake and Haumea.  Eris, Makemake and Haumea -60% of the known dwarf planets-were all discovered here at Palomar using this 48-inch telescope.

A new sky survey, with a new camera, new observing partners and new objectives has just begun at Palomar. It will undoubtedly make new and amazing dicoveries and you can hear about it here in a future podcast.

If you want to learn more about sky surveys, dwarf planets or the 48-inch Samuel Oschin Telescope you can visit the Palomar Observatory’s website at Palomar dash observatory dot org.

For the Palomar Observatory, I am Scott Kardel wishing you “clear skies”.

End of podcast:

365 Days of Astronomy
The 365 Days of Astronomy Podcast is produced by the New Media Working Group of the International Year of Astronomy 2009. Audio post-production by Preston Gibson. Bandwidth donated by and wizzard media. Web design by Clockwork Active Media Systems. You may reproduce and distribute this audio for non-commercial purposes. Please consider supporting the podcast with a few dollars (or Euros!). Visit us on the web at or email us at Until tomorrow…goodbye.