Category Archives: Telescopes

Methods to Remove the Deleterious Effects of the Earth’s Atmosphere on Astronomical Measurements

Question: Would it be possible to improve astronomical seeing on earth using a circular surrounding array of lasers pointing directly into space, which surround the ground based telescope and ionize the air and/or somehow move it away from within the … Continue reading

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Specifications for a First Telescope

Question: I have a question which is while building my first telescope what should be the f ratio of the objective lens and which type of eyepiece should i prefer? The 1.25 inch 25 mm or .965 inch for lesser … Continue reading

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How Far Away Could We See An Alien Civilization Transmitting a Powerful Radio Signal in Our Direction?

Question: If the most powerful transmitter currently used on Earth was used by an alien civilization, what is the farthest it could be to still receive an intelligible signal by the most sensitive current receivers on Earth?  Perhaps the signal … Continue reading

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How Do You Measure the Mass of a Black Hole with Radio Waves?

Question: How can you measure the mass of a black hole with radio waves? What is the mass of a typical black hole?  — Ray Answer: One can measure the mass of a black hole by tracing the motion of … Continue reading

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Why Do You Need So Many Radio Telescopes?

Question: Why do you need so many radio telescopes? Do they all receive exactly the same frequency? How are the signals integrated into something meaningful?  — Ray Answer: You basically hit on a part of the answer in your second … Continue reading

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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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