Astronomy Stack Exchange
Astronomy Stack Exchange

Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

702 questions
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What should I look for in a first telescope for a child?

I'm in a situation that I think many parents find themselves: my son has said that for Christmas he wants "a telescope so that I can see the planets". Which is cool, and I certainly would like to encourage him on this path. But what should I get?…
Vilx-
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How can we focus radio telescopes on a star when the earth is spinning?

Reading about the Star KIC 8462852, it has been said that the SETI project turned its radio telescopes towards the star to search for extra terrestrial radio signals as the star had strange fluctuations in light. How can we point from earth a radio…
Fabrizio Mazzoni
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Should I focus more on Aperture or Focal Length for a telescope?

Let's assume there are three types of telescopes with the following specifications: Telescope Aperture Focal Length -------------------------------------------------------------- Example 1 …
www
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Why are almost all modern telescopes reflectors?

I've noticed lately that reflector telescopes are used much more than refractors. The majority of telescopes I see in telescope shops or featured by people online are reflectors. Even the Hubble and JWST are reflector telescopes. Is the reflector…
chowder
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What limits the usable focal length of telescopes currently?

What barriers - of technology, physics and possibly economy (things that would be possible technologically but are simply too expensive) sets the upper bound on quality of telescopes for observation of the sky in visible spectrum - observing surface…
SF.
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What is the bluest narrow band filter mounted on ground based telescopes?

If we want to check a QSO's lyman alpha narrow band image, could a ground based telescope do that? I mean under the circumstance that its lyman alpha shifts to 3300A.
questionhang
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Do bigger telescopes equal better results?

There are many large reflecting/optical telescopes around the world, just to name a few: the Very Large Telescope, Large Zenith Telescope, and European Extremely Large Telescope. My question is does actually building larger telescopes improve…
koolkid
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Why aren't reflector telescopes built with an offset secondary mirror?

Reflector telescopes (normally?) have a parabolic primary mirror that reflects the light to a secondary mirror which is placed at the center of the telescope. The construction holding that mirror and the mirror itself leave artifacts in the acquired…
kruemi
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How are the world's biggest telescopes cleaned?

How are the world's biggest telescopes, (such as the Very Large Telescope for example) cleaned? My research includes what I have read about CO2 cleaning here. Are there any other ways to cleaning the mirrors? What if we were talking about the…
Juan T
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Can an astronomical telescope view objects on Earth?

I am new to telescopes and I'm planning to buy an astronomical telescope like the "Celestron AstroMaster 114 EQ Reflector". Just curious to know whether it can be used to view objects on Earth (e.g. traffic and people miles away from tall…
Syed Waqas Bukhary
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Can a very powerful telescope show a person standing on the moon from the side rather than from directly overhead?

If we had a very powerful telescope with say a 150-meter diameter, placed in orbit around earth, would it be possible to get a side view rather than a top view of a person standing on the moon?
William
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How would a Fast Fourier Transform Telescope work without a mirror, dish or lenses?

I recently came across a short article mentioning the idea for a telescope built without mirrors or lenses that instead uses an array of antennas and massive computing power to resolve an image. Such a thing will apparently become possible if…
SurpriseDog
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Most important feature of a telescope

I was taking an astronomy test, the following question came up: The most important function of the astronomical telescope is: Resolving power Light gathering power magnifying power focal length The focal length obviously means nothing here, as…
soandos
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Basic DIY Telescope

I am looking for a design of a cheap and easy telescope to build with my 9yo daughter with the only basic requirement being that I'd love to be able to see detail on the moon. Looking around, there seems to be a wide variety of either extremely…
rougon
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Periodic error correction in automatic telescopes

I am starting a study on automatic telescopes and the correction of their periodic error. I found two ways of correcting it : with a CCD camera and manually by recording the error. I was wondering if it could be possible to model the error by a…
user30394
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