Tag Archives: telescopes

How Does a Single Dish Telescope Make Images?

Question: How does a single-dish telescope, such as Green Bank, produce images–at least images of more than one pixel? By physically steering the telescope to aim at slightly different patches of the sky?  — Kent Answer: You have it right!  … Continue reading

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How Do You Distinguish Between People-Made Signals and Those From Space?

Question: You have loads of terrestrial interference, so how do you know the signals you receive are extra terrestrial? — Ariane Answer: The radio signals that we generate ourselves, such as by radar or radio communications, have a specific frequency … Continue reading

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Current and Future Radio Observatories in Antarctica?

Question: I would like to know or find out if you have any information on Antarctic radio telescope/observatories programs or sites?  And I would like to know about future projects on radio telescopes or observatories that will be built in … Continue reading

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How to Turn an Old Satellite Dish into a Radio Telescope

Question: I am a high school teacher and three of my students are trying to build a radio telescope with an eight foot satellite dish. What would your recommend?  — John Answer: Great student project!  There are quite a few … Continue reading

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Can Amateur Astronomers Participate in Asteroid Research?

Question: I neither have a large aperture or fast imaging telescope, neither a large or very sensitive CCD camera. This probably is typical for a lot of amateurs. How can one still truly discover an asteroid in the coming years … Continue reading

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Can Radio Waves be Focused Like Visible Light?

Question: A visit to your Very Large Array prompted the question, “Can we focus radio waves much as we can focus visible light and lasers?” The question is important if aliens try to send us a radio message. If their … Continue reading

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How Did Karl Jansky Measure Galactic Radio Emission at 20.5 MHz When the Earth’s Ionosphere Reflects Radio Waves at This Frequency?

Question: If 20MHz waves are ‘bounced’ by the ionosphere, how is it that Karl Jansky detected 20.5MHz waves coming from the galactic centre in 1932?  Also, what sort of receiver would he have used?  — Brendan Answer: I had to … Continue reading

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Is There a Place Where One Can See Daily Radio Images of the Sun?

Question: Is there a place that posts daily images of the Sun in a radio frequency, perhaps 21 cm, something like SOHO does for shorter wavelengths?  — Donna Answer: Unfortunately, I am not aware of a source for regular radio … Continue reading

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How Can One Tell What Telescope Made an Image of a Deep Space Object?

Question: When looking at an image of a deep space object,  how can you tell what type of telescope was used to take the photo?  — Jeni Answer: Unless the caption or other description of the image lists the telescope … Continue reading

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Why are Telescopes Better at Observing Astronomical Objects than the Naked Eye?

Question: Why are telescopes better than the naked eye?  — Amanda Answer: Well, in fact, there are circumstances when the naked eye is a better way to observe astronomical phenomena than a telescope.  For example, if you are interested in … Continue reading

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