What is Telescope: Definition and 513 Discussions

A telescope is an optical instrument using lenses, curved mirrors, or a combination of both to observe distant objects, or various devices used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. The first known practical telescopes were refracting telescopes invented in the Netherlands at the beginning of the 17th century, by using glass lenses. They were used for both terrestrial applications and astronomy.
The reflecting telescope, which uses mirrors to collect and focus light, was invented within a few decades of the first refracting telescope. In the 20th century, many new types of telescopes were invented, including radio telescopes in the 1930s and infrared telescopes in the 1960s. The word telescope now refers to a wide range of instruments capable of detecting different regions of the electromagnetic spectrum, and in some cases other types of detectors.

View More On Wikipedia.org
Recent contents Top users
  1. kolleamm

    Stargazing Double image in reflector telescope

    Complete reflector novice here. Just got a reflector (using refractor before). I had no problems doing astrophotography with my refractor however with the reflector I get double images. Why is this so? Is this a collmination problem? It's not the camera because there's double images when I...
  2. 1oldman2

    B Kepler Telescope Running in Safe Mode

    Just noticed the Kepler telescope is running in "safe mode" burning precious fuel very quickly. Could be the end of the show for K-2 if they don't come up with a workaround soon. If anyone hears of progress regarding the problem could they please mention it here? Thanks:smile...
  3. pioneerboy

    Stargazing Is a Telescope for Asteroids the Key to Discovering New Main Belt Objects?

    Would such a telescope be useful for discovering new main belt asteroids: http://www.officinastellare.com/products_scheda.php?idProd=29
  4. AstroCody

    Stargazing Diameter of Charles Messier's Telescope

    What was the diameter of the telescope that Charles Messier used to make the Messier Catalog?
  5. Avijit Palit

    Stargazing How to measure a magnifying glass (I want to build a telescope)

    I want to build a telescope and want to know which type of lense is better suit for this. Please anyone help...
  6. D

    Optical instruments: Microscope and Telescope

    What are the different formulas for the calculation of magnifying power of a microscope and a telescope? And how would we use the sign conventions in them?
  7. Brek

    Stargazing Setting up first telescope - need advice

    Hi all, first-time poster here excited to get my first telescope working. The issue: I see the silhouette of the secondary mirror and spider vanes in front of everything I focus on! I read through a similar post here a few years back, but the solution didn't work for me. Details: 6"...
  8. Buckethead

    Stargazing Stellar abberation (water in telescope)

    I've been reading about stellar aberration and was particularly drawn to the experiment where two telescopes are tracking a star but one is filled with water to slow the speed of light down. The results of the experiment show both telescopes to be tilted to exactly the same angle which...
  9. M

    Find Magnification of Reflecting Telescope

    Homework Statement Find the magnification of a 10" reflecting telescope with a focal length of 1250mm and a 250mm eyepiece. Homework Equations 1/f=1/do+1/di M=hi/ho=-di/do The Attempt at a Solution Not really sure where to start. If you could, please explain how you got the answer. Thanks for...
  10. NihalRi

    Stargazing Brightness of objects through a telescope

    Hi my question is about how the brightness of stellar objects is effected when we look at them through a telescope. Firstly when I looked through a telescope I noticed there were more stars I could see. Is the reason because a telescope can gather more light than our eye or does it have...
  11. davenn

    Stargazing The James Webb Space Telescope construction

    cool article on the progress of the JWST constructionhttp://www.space.com/31838-james-webb-space-telescope-mirror-assembled.html?cmpid=NL_SP_weekly_2016-2-05Dave
  12. JoAstro

    Stargazing How to calculate the amount of light a telescope collects?

    Having the unaided eye's pupil to be 6.4mm and the diameter of a telescope 8-inches, how can I calculate the amount of light the a scope collects over the human eye?
  13. tesselate

    James Webb space telescope and fundamental physics

    Does JWST has any significance in fundamental physics research? What kind of questions would we get answers to?
  14. Ellie Snyder

    Black hole calculations, the "Event Horizon Telescope"

    Homework Statement Soon astronomers will be imaging the “shadow” of light from the event horizons of black holes. Since black holes are very small, this achievement seems impossible. Nevertheless, it is possible for three reasons: 1. Supermassive black holes have large event horizons. 2. Radio...
  15. J

    Stargazing Basics of Using a Telescope - Locating Stars (RA)

    Hello pf, I have been trying to grasp the concept of RA. I have read through a few books and I know that it is measured eastwards from the point on the celestial sphere where the Sun crosses the celestial equator at the vernal equinox. I just want to check I understand this correctly. Does it...
  16. P

    Homemade Cosmic Microwave Background detector

    Hi Guys, I studied physics for my bachelor but still I am not a super expert, although I am still working closely to physics (but not so much astronomy). I was wondering if it would be possible to build a radio, or some other devise (any ideas?) that could be tuned at the frequency where the...
  17. GiantSheeps

    Stargazing Remote Controlling Truss Dobsonian Telescope?

    Is it possible to rig a Truss Dobsonian telescope like this one so that you can control it remotely from inside of a building while the telescope itself is on the roof of the building? Then is it possible to attach some sort of adapter to the telescope that would allow you to hook up a camera...
  18. ayush solanki

    Stargazing Some tips for a better experience of stargazing using 76 mm telescope

    I bought the celestron firstscope about 4 to 5 months ago.in the beginning I was pretty excited and enthusiastic but as time wore on,I found myself away from the scope.now I want to restart astronomy but I would like some tips to make it more fun and interesting so that my scope don't end up...
  19. kelvin490

    Why an array of telescopes is used?

    To increase the resolution of an instrument, smaller wavelength and larger aperture is desirable. It is mentioned in some textbooks that the "effective" diameter of a telescope can be increased by using arrays of smaller telescopes. I just wonder why it is possible because every telescope is...
  20. Glenstr

    Stargazing Got my First Telescope | Celestron Sky Prodigy 130 | Astrophotography

    Over the last year or so I've been thinking seriously about getting a telescope, having my eye on the Celestron Nexstar 6SE model or getting a slightly smaller 5" model that's more automated for about the same price. Well, yesterday my mind got made up for me as it was my birthday & my wife...
  21. S

    Stargazing Is there a proper way to clean a telescope mirror?

    Hi guys! I have a Levenhuk telescope and still have a question what is the best way to clean the mirror? Thanx for the help.
  22. kos

    Telescope Images: Light Deflection & Alien Observation

    http://www.askamathematician.com/2013/04/q-what-kind-of-telescope-would-be-needed-to-see-a-person-on-a-planet-in-a-different-solar-system My speculative question on the subject is in the sphere of Einstein General relativity applying to the problem. So we all now know that when light passes...
  23. V

    Stargazing Create homemade reflector telescope by own

    Can anyone please provide some web links or tips for making a homemade reflecting telescopes by own?
  24. RandyD123

    Very Powerful Telescope to see 10 light years away at high resolution....

    Lets suppose I had a very powerful telescope and I could see 10 light years away. Would I see cars and people on that planet as they were 10 years ago? Would I actually see the people moving and the cars moving on the ground?
  25. H

    Stargazing Can I Make My Own 8 Telescope with These Required Instruments?

    hello , any one give me an information that how i make my own 8" telescope...And for making telescope which instuments are require
  26. Ibrahim Hany

    Stargazing Problem in making a small refracting Telescope

    It sounds silly to ask such question or stumble in such problem, indeed! But I was willing to make some small telescopes for young friends of mine, to encourage them to delve in the skies. So, I bought: 1. Double concave, spherical glass lens, with a focal length of approx. -75mm and diameter...
  27. M

    Stargazing Upgrade Your Telescope Today: Top 10-Inch Aperture Options Under £600

    I've been to a starparty and realized my telescope is well underpowered and for what I want to view. My budget is £500-£600 and I was looking for something with a ten inch aperture. I was looking at the Orion xt10 classical with barlow set or the Skywatcher skyliner 250px dobsonian. Could...
  28. D

    Telescope probes and warp track

    1st tope, in my sci-fi universe let's say there is a warp drive that can power a ship that can travel 10*c. One of the first things I have people doing is coming up what is called "The Big Picture Project" which is installing this drive onto probes and sending them out unmanned and have it so...
  29. W

    How to Figure Required Telescope Diameter?

    A awhile ago I wrote a program to calculate various things like maximum resolving power of a given telescope's primary mirror, angular diameter of an object of a given size from a given distance and mirror diameter required to see an object of a given angular diameter. However, I seem to have...
  30. B

    Stargazing Why is there no Hubble-like telescope on the International Space Station?

    why is there no telescope like Hubble on the international space station/? as i know, the iss is only 150 km lower in orbit than the Hubble space telescope, and is at different inclination. Having people around is pretty convenient i think, so replacing parts and doing regular maintenance would...
  31. S

    Stargazing Reflector telescope, what to do?

    Hey guys! My dad bought me a reflector telescope (Levenhuk Strike 120 plus) but I am having a hard time figuring out how it works. I managed to assemble the telescope with the help of my dad but we cannot seem to see anything through it. Any suggestions what could possibly be wrong with it? Or...
  32. Shreyas Shree

    Optical Making a Dobsonian Telescope DIY

    I am going to make a Dobsonian telescope. Primarily a 6" f/8. I have no idea what the secondary mirror size would be an its distance from the centre of the primary. I have been told that if the secondary is too small then the effective aperture would be reduced. And i do not understancd these...
  33. R

    Stargazing Is this a realistic design for a kilometer wide telescope?

    I'm just a bridge engineer and amateur astronomer, so I'm hoping someone here with more advanced expertise in light waves and reflective surfaces can help me. Basically I was wondering how big a space telescope's primary mirror would have to be in order to view an exoplanet 10 or so light years...
  34. 2

    Stargazing Understanding reflecting telescopes?

    I have been looking at these diagrams: From the following link http://www.astronomynotes.com/telescop/s3.htm And I just can't seem to figure out why the first telescope design doesn't show a shadow and in the second why the presence of the secondary mirror, and the hole, do not affect the...
  35. 2

    Stargazing Quick question about telescope classification

    I am slightly confused about what the term 'astronomical telescope' covers. My textbook seems to be implying that astronomical telescopes are refracting telescopes with an objective and eyepiece lens, and reflecting telescopes are separate to astronomical telescopes. On the other hand I have...
  36. 2

    Stargazing Understanding the Field of View of Reflecting and Refracting Telescopes

    I don't quite understand the concept of field of view of a telescope... Specifically, I am trying to understand the advantages of reflecting and refracting telescopes compared with the other, and my textbook says that "Refracting telescopes have a wider field of view than reflectors of the same...
  37. 2

    Stargazing Viewing stars through a refracting telescope?

    Hello! I am learning about refracting telescopes and am slightly confused. I have read that a refracting telescope will magnify planets, but not change their brightness, but will not magnify stars as these will remain as point objects. It just makes the stars appear brighter. I am slightly...
  38. P

    Stargazing How Do Lasers Work in Telescopes to Capture Images of the Universe?

    Well I was watching this documentary.there was reference to laser telescope.it use laser to get images of universe.I know the basic principle.it shoots out laser is space and get images from reflected light.but is that lasers really powerful enough to get images of objects which are far in the...
  39. W

    Understanding Telecentricity in Newtonian Telescopes

    Homework Statement See the image I uploaded. Homework Equations Paraxial approximations The Attempt at a Solution I think the image is formed after the ocular, and I understand the system is afocal. The magnification is also less than 1, but the angular magnification is >1. What I am stuck...
  40. K

    Finding the angular resolution of a telescope

    Homework Statement An optical telescope has a diameter of 1.5m. It is placed at a site with 'seeing' of 1.0''. What is the expected resolution in arcseconds from observations made with the telescope at 1000nm? Give your answer to one decimal placeHomework Equations Theta (rads) = 1.22 *...
  41. T

    Understanding Angular Magnification in Simple Magnifiers and Telescopes

    So basically, in the text below, they say that maximum angular magnification is achieved when the object is placed 25 cm from the eye, i.e. at the near point. The minimum angular magnification is achieved when the object is placed at the focal length. However, for the chapter on the telescope...
  42. GiantSheeps

    Stargazing Are there astronomy competitions?

    I run an astronomy club at my school, and I recently discovered that the robotics club gets $2000 from the school every year to build a robot. They then go on to compete in tournaments with that robot, so that justifies the $2000. It would be great if I could get the school to give us $2000 to...
  43. Kelson Adams

    Stargazing Astrophotography -- Best Telescopes?

    What are the best telescopes for amateur astronomy? I realize that there are many differences between telescopes, but let's face it. If I'm going to invest in a great telescope, I want it to produce a high-resolution image and to survive for a significant amount of time. -- and I absolutely do...
  44. Xsnac

    Stargazing Research with Ritchey–Chrétien 400 mm telescope

    Hello! I'm a first year undergrad student and I have the oportunity to do research durring summer with an Ritchey–Chrétien 400 mm telescope. Can you guys recommand me something to research? I don't even know where to start with my search for interesting topics that are not too hard and that will...
  45. GiantSheeps

    Stargazing Help with telescope/observatory data and images

    I was wondering if anyone would help me get my hands on some telescope data and images of exoplanets. I know they must exist somewhere in databases on the internet, but I haven't been able to find them myself. It would be great if one of you could show me where I could get them or even if you...
  46. 2

    How Does Angular Resolution Differ from Other Types of Resolution?

    The Wikipedia definition of angular resolution is 'Angular resolution, or spatial resolution, describes the ability of any image-forming device such as an optical or radio telescope, a microscope, a camera, or an eye, to distinguish small details of an object, thereby making it a major...
  47. N

    Reading of planets billions of light years away

    We can see galaxies/planets light years away determine their composition such such as if they have water et cetera. My question is if light takes billions of years to reach us from there how is that we can determine such things? Is the speed at which a telescope can zoom faster than the speed at...
  48. D

    Will Light Speed Travel Affect Perception of Andromeda Galaxy's Age and Distance?

    Andromeda galaxy is measured as about 2,500,000 light years from me as I am at rest with respect to the Earth. Using luminosity of known objects in Andromeda. I have a close to light speed spaceship which is pointing toward the Andromeda galaxy with a camera mounted on the nose cone. I am going...
  49. GiantSheeps

    Best way to see Andromeda galaxy

    I just recently got a dobsonian reflector telescope, (Orion SkyQuest XT8 PLUS Dobsonian Reflector Telescope) and I was wondering what the best way to see the andromeda galaxy would be using the telescope? Of these, which would be the best eye piece for that sort of thing?: Orion 2" 28mm...
  50. C

    Ray optics of a telescope question

    Its an often prøven fact that a convex lens focused rays parallel with the optical axis into the focal point of the lens, but what about rays that are parallel with each other and with a small angle to the optical axis? In ray diagrams with telescopes (such like the one below) one often draws...
Back
Top