Podcaster: Dr. Al Grauer
Title: Travelers in the Night Digest: Eps. 491 & 492: One Half Inch & Not Human
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Organization: Travelers in The Night
Link : Travelers in the Night ; @Nmcanopus
Description: Today’s 2 topics:
- What factors control the sharpness of our telescope’s images and how acting together these processes determine the faint limit of the asteroids we are able to discover.
- Naked eye views of the Cosmos inspired countless generations poets, scientists, mathematicians, musicians, artists, and creative works of all kinds. Now it is likely that 80% of the children born in the United States will never see the Milky Way or a meteor streaking through the night sky.
Bio: Dr. Al Grauer is currently an observing member of the Catalina Sky Survey Team at the University of Arizona. This group has discovered nearly half of the Earth approaching objects known to exist. He received a PhD in Physics in 1971 and has been an observational Astronomer for 43 years. He retired as a University Professor after 39 years of interacting with students. He has conducted research projects using telescopes in Arizona, Chile, Australia, Hawaii, Louisiana, and Georgia with funding from NSF and NASA.
He is noted as Co-discoverer of comet P/2010 TO20 Linear-Grauer, Discoverer of comet C/2009 U5 Grauer and has asteroid 18871 Grauer named for him.
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Transcript:
491 – One Half Inch
In an asteroid hunter’s telescopic images, potential Earth approaching objects appear as tiny, faint, fast moving, points of light. Fuzzy, spread out, asteroid images due to atmospheric and or equipment produced distortions can cause important objects to slip through an asteroid hunter’s discovery images undetected. My Catalina Sky Survey teammate Jess Johnson is researching what factors control the sharpness of our telescope’s images and how acting together these processes determine the faint limit of the asteroids we are able to discover. Interestingly a telescope in orbit looking down on Earth is able to see much finer detail than a similar sized one on a mountain top looking up. Both are observing through the same layer of Earth’s atmosphere, however, the big difference lies in layer of air surrounding the ground based telescope. Heat sources near the telescope cause turbulence which blurs and degrades the images essentially transforming the telescope into a much smaller version of itself. Amazingly an important source of image degradation is the 1/2 inch thick layer of air immediately above the surface of the telescope’s primary mirror. Jess’s work emphasizes that a careful monitoring of the temperature at a number of different locations in the observatory environment and using fans and other techniques to minimize temperature differences will restore the power of our telescopes so that they can detect much fainter objects than is currently possible.
492 -Not Human
From the time 3 million years ago that our ancestor Lucy walked in what is now Ethiopia until the widespread use of electric lighting began in the 1880s the changing panorama and awe inspiring beauty of the natural night sky was available to most human beings. These naked eye views of the Cosmos inspired countless generations poets, scientists, mathematicians, musicians, artists, and creative works of all kinds. Now it is likely that 80% of the children born in the United States will never see the Milky Way or a meteor streaking through the night sky. Examples of shows that the Universe produces for you are the Perseid and the Geminid meteor showers which occur every August and December, the panorama of the magnificent Milky Way with it’s star clouds and clusters, a nearby galaxy, and the ever changing movement of the Moon and planets. To see for yourself visit a place like the Cosmic Campground International Dark Sky Sanctuary that you can find on the darksky.org website and invite a friend to go with you. If you time your visit during the three or four days on either side of new moon you will be able to see the faintest objects. All you have to do is not look at your cell phone or another bright light for 30 to 45 minutes. Your eyes will become dark adapted and you are ready. Bring a red filtered flashlight, star maps, binoculars, warm clothes, a lawn chair, snacks, and sit back and experience the wonders of the Universe with your very own eyes.
For Travelers in the Night this is Dr. Al Grauer.
End of podcast:
365 Days of Astronomy
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