Questions tagged [telescope]

Questions related to the physical instruments for astronomical observations.

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122 views

lousy mirror corrected by software

Would it be possible to get a terribly shaped mirror, like a large sheet of something reflective, give it a general shape like a telescope mirror, but not anywhere near as precisely shaped as in a ...
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171 views

Event Horizon Telescope Data Cleanup

I was wondering how the researchers were able to minimize or neutralize confirmation bias regarding the data collected? As I understand it, the algorithm pruned much of the data, which would make ...
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58 views

Tools for creating a multiwavelength view of the sky

Not sure that this is the correct place to ask this question, but here goes. I am trying to find tools to accumulate image data (preferably in FITS format) on a given (RA, Dec)-coordinate of sky. ...
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197 views

How to choose portable, yet powerful telescope

Due to the nature of my job, I have to spend log periods of time (4 - 6 months each), at different countries across Europe, Middle East and Far East. I have a 12 Inch Dobsonian at home, but I rarely ...
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467 views

How do I find the RA of sunset and sunrise in a specific location?

I want to make some observations with a telescope in Hawaii on Mauna Kea but I am living somewhere else (not Hawaii) and I want to plan a night's viewing on the Hawaiian telescope. How do I find the ...
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If we built one hundred 3m telescopes and point them to a single star what would be the final resolution? [duplicate]

We'll mount all of them in a same location and connect them to each other (like VLT) so they will combined all the results and will produce some staggering images however my question is, would they be ...
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259 views

Why did the Event Horizon Telescope take so long to take a photo of a black hole?

The Event Horizon Telescope is in the news now because they are about to release the first ever picture of a black hole. They have been working on this since 2006. Why did it take 13 years to produce ...
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Why does the Moon appear to be flat?

There's no way around it: when I look at the full moon at night it looks like a mostly flat disc, with at most a bit convexity in the middle. Phases of moon look like a full moon seen through a cut-...
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First night on a telescope questions

So I recently got into astronomy and I am using my fathers old Meade EQ1-B reflector telescope. This is my first night using it and I have come across a few questions. To begin, the telescope was left ...
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Why can’t I see any detail on planets?

I really want to know why I can’t see detail on planets. This summer my Dad and I went on a trip to Utah I went outside to look at the planets and couldn’t see detail on Mars, Saturn, and Jupiter. ...
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Relation between angular resolution and aperture?

The angular resolution of a telescope is given by $\frac{1.22\lambda}{D}$. This should mean that the smaller the aperture D, the higher the angular resolution. But it is exactly the opposite - why?
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Minimum telescope needed to see the rings of the Saturn

I am a total novice. My daughter, likes Saturn. Since Saturn is so close I thought it was a good time to view it with her. What are the minimum needed telescope specs? Update: Can answer answers be ...
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Mars looks like a blur

I took my telescope out tonight (I am new, just got the telescope a few days ago, it's my first one) and I was observing Mars, however all I see is just an bright orange circle, with no surface detail,...
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How do focal length, angular magnification and field of view relate?

The larger the focal length the larger the angular magnification The smaller the focal length the larger the field of view. I don't understand why this applies. I'm talking specifically about ...
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997 views

Is it practical to build a giant telescope in Moon? (Considering the fact that the atmosphere of moon is very rare)

China's FAST (Five-hundred-meter Aperture Spherical radio Telescope) is the largest radio telescope in the world.(This is huge!!!) As we all know Space Telescopes are better than Earth-Based ...
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Suggestions for a beginner-friendly telescope

I'm hoping someone can point me in the right direction for a beginner-friendly telescope for my family. My husband has mentioned wanting a telescope off and on for a few years, but he's never delved ...
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257 views

Will I be able to see both Jupiter and Saturn at the same time in my Astromaster 114?

I have a Celestron Astromaster 114 Newtonian reflector telescope. The specs: aperture: 114mm focal length: 1000mm focal ratio: f/8.77 I also have a t-ring so I can connect a Nikon camera to it. Will ...
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599 views

Split telescope into two eyes

I am looking for an appendage to attach to the end of a telescope which splits the image into two eyes instead of one. Does such an appendage exist?
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Why do we use solar filters instead of simply reducing aperture of the telescope?

Everywhere I read that to view the Sun in the telescope, one has to use a solar filter. The filter must be handled carefully to avoid any holes in it and even mustn't be stretched so as to avoid ...
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336 views

VLT interferometry vs E-ELT?

If the VLT (very large telescope) can use interferomerty to act as a 200 meter mirror, then why are they trying to build the 39 meter E-ELT? What advantage does the E-ELT have, if the VLT can act as a ...
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Why are telescope mirrors nearly flat?

My understanding of telescope mirrors is that they are (generally speaking) a slice out of an imaginary sphere. The center of this sphere is the focal point of the telescope, where the detector is ...
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Do telescopes harm while observing sun through them?

I don't know whether we can observe a sun through a telescope. But if we can then will it harm our eyes and if such telescopes exists what is their configuration?
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Do telescope measurements (in meters, usually) measure in a straight line, from edge to edge, or follow the curve of the mirror?

Somehow, no site or book or magazine has clarified this question for me.... Perhaps I am an idiot, but, Is the parabolic primary mirror on the new James Webb Space Telescope (JWST) 6.5 meters from ...
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Orion Skyquest xt8i Intelliscope Dobsonian Telescope Lens

I have the telescope in the title, which camps with 10mm and 25mm eyepieces. Both cannot really see anything in detail past the moon. All planets look like stars. What are good eyepieces for seeing ...
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Constructing a periscope/telescope - trouble with lenses

Not sure if this is the best place for this, maybe physics would be a better fit, but I'm trying to build a periscope and am running into an issue. Traditional mirror periscopes work well, but when ...
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Can we get a picture of Oumuamua with Hubble Space Telescope?

Can we get a picture of Oumuamua with Hubble Space Telescope? If not, what are the reasons? Answers why other telescopes might fail to get a picture of Oumuamua are welcomed as well.
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How to use an app to help find deep sky objects in general, either attached to a telescope as a finder scope or held on hand?

A friend with a young child asked me for a beginner scope recommendation of less than $300 to see the planets as well as some brighter deep sky objects in a relatively dark suburban location. My first ...
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What's the rationale behind the false colours in solar observation photographs?

Images from SOHO, SDO and other sun observatories are often coloured differently for different wavelengths or temperatures: http://www.nasa.gov/mission_pages/sunearth/science/Sun-Wavelength-Chart....
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If thousands of exoplanets have been discovered, why haven't we discovered planet 9 yet? [duplicate]

According to NASA, we've discovered 3,453 exoplanets so far [1]. With some of the farthest being at 13,000 light years away [2]. This would suggest today scientists have a really advanced capability ...
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What's the difference between optical telescopes and solar telescopes?

Solar radiation is strong. Following problems for solar telescopes may be telescope site selection and temperature control. I wonder the telescopes themselves and their instruments are different?
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How to make a telescope for viewing planets, moon and DSOs using a convex lens of aperture 100 mm and focal length 200 mm and other lenses at home?

I wanted to make a telescope with DIY things lying around in home. I read up that the aperture was a very important aspect and thus bought a convex lens with 100mm aperture and 200mm focal length, to ...
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Distance between each dish in an array telescope configuration

In an array telescope configuration, like VLA and ATA, what dictates the distance between each dish?
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Any cheap (less than 100 euro) telescope for observing Jupiter? [closed]

The moon is not challenging. I would like to observe the big planets and their rings.
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Pictures of large galaxies

The Andromeda Galaxy is tens of thousands of light years in diameter. That suggests that the most distant stars in the Andromeda galaxy is up to tens of thousands of years "behind" in their orbit ...
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Trying to use Canon 60D DSLR with Skywatcher 130P. Can't focus image

I have a Skywatcher Heritage 130P FlexTube Dobsonian Telescope. It works well, I can see lovely stars, planets, moons of Jupiter etc. It came with two eye pieces (1.25 inch): 10 mm and 25 mm. I also ...
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If we've only observed Oumuamua as a single pixel, how can we know its shape?

On a separate Oumuamua question (Oumuamua alien space junk?), I was confused how shape could be inferred from a single pixel, per another user's (@Uwe) comment. It was suggested I ask this question ...
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What are some good telescopes for a programmer? [closed]

I’ve never purchased a telescope and I was considering buying one. However, I wasn’t sure what to look for. I love to tinker and so a telescope that I can program with libraries such as SPICE would be ...
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109 views

Is remote measurement of isotope ratios possible, or must a sample be aquired

Is it possible to measure to measure isotopic abundance of remote astronomical objects - ie measurement without having a sample to feed into a mass spectrometer? Do different isotopes show any ...
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Equation to find distance between objective and eyepiece

I have a home made astronomical telescope with 100 cm objective lens and 5 cm eyepiece.when viewing an object in infinity the distance between eyepiece and objective is 105 cm. So how could I ...
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284 views

Why are solar telescopes built on lakes?

The telescope big bear is located in the Southern California. According to the wikipedia page, water can cool the observatory. Is it better to build it on a cold high mountain with stable and clear ...
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85 views

Is there a complete guide on how to use telescopes?

tl;dr As said by @uhoh in the comments, is there A Big Book of Telescopes? i.e: Is there some kind of media that gives a complete treatment to telescopes? I am relatively new to Astronomy.SE. I wanted ...
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241 views

Can a telescope ever increase the apparent luminance of an extended object?

From what I know about common telescope designs, telescopes don't increase the apparent luminance of extended objects compared to the luminance seen with the naked eye. In this sense extended objects ...
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145 views

What are the benefits of a large refracting telescope?

Currently, refractor telescopes are limited in aperture because gravity will deform the main lens over time. According to Wikipedia the largest practical refracting telescope is 1m. If we were to ...
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90 views

Question about the relevant physical parameters to build a backyard observatory

I live in a big city: São Paulo, Brazil. I would like to build a simple telescope dome to do some amateur sky obseravtions. But the whole project lies on the viability to see something interresting ...
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145 views

Smallest body that can be observed from Earth?

What is the minimum size of an object that can be observed from Earth with our most powerful telescope? I understand that the answer depends on how far the object is from Earth. For the sake of ...
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68 views

How common are telescopes with the finder scope on the right side?

Are there telescopes where the finder scope is mounted on the (upper) right of the body? Are they common? If not, are there any ways around this (e.g. can I mount a lightweight telescope "...
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646 views

Photometer vs. CCD-camera

The Wikipedia article on photometry says that These have largely been replaced with CCD cameras that can simultaneously image multiple objects, although photoelectric photometers are still used in ...
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Am I using my Celestron 8 Schmidt-Cassegrain telescope correctly?

I became interested in astronomy a few years ago and started with a Celestron AstroMaster 70AZ refractor telescope. That seemed nice, and I wanted to upgrade to a go-to telescope that was also more ...
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121 views

How can a galaxy in-between our view and the galaxy behind it have a 'lensing effect'?

In this article, the author writes: This galaxy is so distant that it would have been invisible without the gravitational lensing effects of a large galaxy cluster called Abell 1689, located nearly ...
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What kinds of technologies are required to directly image exoplanets

I have read that immensley powerful telescopes such as the European Extremley Large Telescope will be able to directly image the atmospheres of exoplanets, and even determine their rotation rates. I ...

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