March 28: A visit to PS 282 in Park Slope, Brooklyn

Today, March 28, 2011, in the morning three Columbia University Astronomy Department graduate students and one undergraduate visited PS 282 in Brooklyn with two telescopes in tow. As the moon was a few days past third-quarter phase, it was possible to see both the sun and the moon! 120 first graders braved the cold and waited patiently for their turn to take a look at each of these celestial objects. Many of them had never looked through a telescope before and were very excited that they could see dark and light spots and even a few craters on the moon's surface as well as sunspots on the Sun. At the end of the visit, each class was presented with 3D images of the Sun, posters, and some CD-ROMs for distribution among the students.

Many thanks to the volunteers who made the trek out to another borough to help raise astronomy awareness.

March 25, 2011: Ancient East Asian Astronomy

This past Friday we had an excellent lecture on ancient east Asian astronomy given by graduate student Joo Heon Yoon. The talk focused on ancient astronomical techniques from Joo's homeland of Korea. Joo described how modern astronomers and historians can use observations made by ancient astronomers to constrain both scientific models and historical theories.

Hazy weather obscured the view for most of the night, but our roof volunteers persevered and gave visitors views of M44, the Orion nebula and Sirius. Our roof volunteers Neil Zimmerman, Richard Darst, Bryan Terrazas, Dan D'Orazio and Ian Allen did a great job. Graduate student Yuan Li also showed visitors 3d visualizations astronomical topics spanning the universe from the solar system to the formation of large scale structure. A few people stuck around in the lecture hall for slide shows on star clusters and exoplanet detection led by Christine Simpson.

Thanks to all our volunteers and to the 120 people who came to our
event.

Christine

March 11, 2011: IceCube Astronomy

On March 11, one of our senior undergraduates majoring in astrophysics, David Fierroz, gave a talk about a neutrino telescope that he worked on last summer, IceCube. David talked about how IceCube was built at the South Pole and he described the long trip to get there. About 150 visitors came by to hear how the telescope is opening up a new branch of astronomy, discovering objects in a completely new way. As arguably the largest telescope in the world, IceCube will be able to observe some of the most extreme phenomena in the universe including supernova, and supermassive black holes at the centers of galaxies.


Afterwards, one of our incoming graduate students, Jia Liu, gave a talk about a standard day and night at Kitt Peak National Observatory. Also, one of our graduating students explained how Stellarium works and showed the conjunction of planets over the year. While the weather was not great enough to look at stars through the telescope, we were able to give tours of the telescope roof and dome, and even look at the moon.

Family Astro: Telescopes!

We had over 50 people visit for Family Astro Saturday on March 5, 2011 including both children and parents. The topic was telescopes. The kids learned about different types of telescopes, including the Hubble space telescope and the way that astronauts fixed it. Then everyone got a chance to observe pictures they drew of objects in space through small telescopes. In one activity, kids pretended to be light moving at different speeds as it was being bent, just like it would be as it went through a lens. We also made models of telescopes using paper cups, and used balls of different sizes to show how different types of telescopes are able to catch different wavelengths of light. Finally, we watched a 3D movie about galaxies. Thanks to the volunteers, Jana, Jennifer, Lia, Brandon, and Yuan for helping out and making the event a success!

February 25, 2011: The Gamma-ray universe

Last Friday, about 70 people attended a lecture by Dr. Rene Ong from UCLA about viewing the universe in gamma rays. Dr. Ong talked about the unique issues with observing the most highly energetic photons and also gave the audience a virtual tour of VERITAS, an array of four telescopes in Arizona that monitor the night skies for the Cherenkov radiation that emanates when extremely energetic photons collide with the atmosphere. A number of astronomical objects have already been detected by VERITAS and other telescopes around the world that are similar in design to it. These observations have complemented observations made by other gamma-ray observatories including a space-based gamma ray observatory that was launched two years ago: the Fermi Gamma Ray Space Telescope. These observations are probing some of the most energetic environments of the universe and are giving us information about what the conditions are like in environments where there are extreme physical conditions including neutron stars, black holes, active galaxies and quasars, and microquasars.

After the lecture, the skies were unfortunately too cloudy to allow for observing, but a small tour did happen for those who wanted to see the facilities at least. Additionally, Columbia University graduate student, Duane Lee, gave a slideshow presentation featuring the images from Astronomy Picture of the Day. This website updates daily with a new image of astronomical import with an explanation written by a professional astronomer. Many astronomy enthusiasts mark the page as their homepage to give them a taste of astronomy every day when they log-on to their computers.

February 11, 2010: Galactic Sleuthing Lecture and Public Observing

This past Friday, Dr. Allyson Sheffield, a current post-doc of the Columbia Astronomy department, gave a talk entitled, ''Galactic Sleuthing: Unraveling the Milky Way’s Past.'' In her talk, Allyson described two prevailing models for galactic formation. First, 'monolithic collapse' posits that a galactic-sized gas reservoir (of Hydrogen and Helium) collapses all at once, creating an old population halo of stars first and then flattens out into a disk composed of younger stars. Second, she presented the theory of 'hierarchical merging' that posits that galaxies are built up from the accretion of smaller galaxies and the merging of bigger ones.

Allyson then talked about how we can determine which scenario better describes the evolutionary path of our own galaxy by looking at both the group motions of stars and their shared chemical abundances. By showing us data and simulations by Rodrigo Ibata and his collaborators and by our very own Prof. Kathryn Johnston, respectively, she showed us how the merging Sagittarius dwarf galaxy was discovered by surveying stellar velocities in the galaxy along with models that describe how the dwarf galaxy would currently look which were later confirmed by additional chemical abundance observations.

Finally, she showed us how one can merge the two indicators of common ancestry to look at moving groups closer to us and determine if evidence for other accreted dwarf galaxy remnants remain in the galaxy by looking at the spectra of stars with similar peculiar velocities. She found that she could likely link certain groups to larger ones seen in the galactic halo stellar streams by models that would predict the location of these peculiar stars. Given her research and the other research she presented, we learned that merging plays a significant role in galaxy evolution and that one can recount this evolution based on remnants of past accretion events.

We had a great turn out and our attendees made full use of our facilities by watching astronomy visualizations on our 3-D wall, ran by graduate student Jana Grcevich, and by going to the roof to stargaze. It's cool to think that many of the stars we observed, including our own, exhibit group origins or movements that were probably even more defined in the past.

Thanks to the 8 volunteers and the 130 people who attended our lecture and observing night!

Sidewalk Astronomy returns to Harlem

Freezing temperatures and fierce winds did not stop Alex, Jennifer, Brandon, and Neil from carrying on with stargazing plans at 125th street last night. Setting up two telescopes in front of an H+M store, they showed about 100 passersby a great view of the waxing crescent Moon. During the bus ride to the observing spot, Alex snapped a shot of the other volunteers and their scopes. All are looking forward to repeating the excursion on warmer evenings in the months ahead.

-Neil