Telescopes Definition and 87 Threads

[Mentor Note -- Discussion spun off from the main JWST thread] Yes, the apparent hexagonal shape of that star is due to the diffraction within the telescope optics (optical filter characteristics may also have played a role). For clarity, we're talking about this star: They are (images...

My notes say that the Resolution of the Aperture(in the Electric field of the wave) is the Fourier transformation of the aperture. Then gives us the equation of the aperture: and says that for the circular aperture in particular also: My attempt at solving this: We know that the Fourier...

I would like to know what will be the visibility from the portable telescope aboard the International Space Station. What could they potentially view, and what are (at least some of) the things they are known to have looked at? Presumably they use it *inside* the ISS and not outside, and are...

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It appears that many texts on astrophotography and telescopes for amateurs tend to avoid mathematical formulas, as such, they are of little use to do some practical calculations. What I am interested in is: Magnification Image scale Focal length Focal plane and sensor plane! (CCDs!) Focal-ratio...

I was wondering how the resolution is of a observatory station and compare that to its field of view? Higher rez with larger field or higher rez with more narrow field but much more scanning across the sky to create full images?

Elon Musk's Starlink orbital internet communication system is presently seen as a detriment for observing the cosmos by ground observers, but have astronomers thought asking Elon Musk if he would consider mounting compact low-energy telescopes on the back of his orbitals, facing away from Earth...

My answer would be (e) but is it just the same as (b)? So there are 2 correct answers? Thanks

This article seems to say so. https://www.accuweather.com/en/travel/the-best-stargazing-sites-in-the-us/632888

Excluding planets and given normal dark skies, what minimum aperture size of a (non-refractor) telescope is required to just start getting hints of colour in deep sky objects like nebulae and galaxies? I mean in real time, unaided eye, no photography.

1903.11078.pdf Would it not be cool to find an exoplanet from your back lawn. This paper is to introduce an online tool1 for the prediction of exoplanet transit light curves. Small telescopes can readily capture exoplanet transits under good weather conditions when the combination of a bright...

I live in a small town and would like to make some observations today. However i don't have a solar aperture filter, i only have an eyepiece filter of which i do not trust. So is there any household items, materials i could use safely to save me from from ordering on the net and waiting...

I'm hoping this is ok to post here as I imagine some of you will know the answer. I like to read the insights on this forum, but generally don't believe my command of the subject matter lends itself to the discussion. That said, I enjoy the night sky and am looking to get a portable telescope...

For an optical telescope, light pollution is a problem and that's why put ground-based telescopes in remote places where there isn't much light. However, aren't we bombarded by radio waves from satellites for our phones and TVs? How do radio telescopes remove those?

I just finished up some hypothetical maths, as I saw yesterday that someone else on the internets repeated my repeated assertion that a really big telescope lens would collapse into a black hole. I don't think that's correct. Now, the original author of the claim, claims to be an...

A reasonably read and educated laymen, would response to a claim that science and technology still have no means to detect a big asteroid collision with earth, by saying that according to what he read and saw in communication channels reliable enough, an object of that size on course to hit...

the largest telescope in the world has an aperture of 10 m. According to the fresnel distance this makes ray optics valid for it, for a wavelength of lightsay 500 nm, uptil a distance of 2 * 10^7 m. I have read that after the fresnel distance, diffraction tends to dominate. But telescopes tend...

Homework Statement I have the following variables: f = .93 m f(e) (eyepiece) = .0082 m distance toJupiter pj = 588 E^9 diameter of Jupiter dj = 139822 E^3 Find the height of the image of Jupiter created by the objective lens of a telescope. Homework Equations M = -q/p q = f Where M is the...

I was just wondering. According to Lorentz transformations, if two events are simultaneous in one reference frame, they will generally not be simultaneous in another. The time difference that I get between the two events in the other reference frame is \Delta t^{`} = \gamma\beta\Delta x...

Hello, I am currently considering on buying a telescope to do some of my own research and for sight seeing. Any recommendations? I would prefer to have a telescope that requires me to use code or at least a computer so I can familiarize myself with the mechanics.

So how can the photos of distant galaxies have no nearer stars in front of them? Or photos of nebulae? I feel like there are so many stars.that it would be impossible to take a photo of a distant object without a star in front of the photo blocking the way. Or is it luck that there are no stars...

Hello all, First of all thanks for taking the time to look at my post, and thanks ahead of time to those willing to answer my question. I've always loved Astronomy and have done quite a bit of self-study over the years. I have a pair of binoculars but want to get a telescope. I'll start by...

I feel the need to make sure my Dobsonian scope is working at its best. I was considering a conventional (?) red LED collimator but I suddenly begin to see these Artificial Stars on sale. Would that be a better way to go? Anyone have experience of them? Looking at real stars tells me that the...

When you look up a ray diagram for a telescope you get the following: From reading my book it seems clear that the objective lens forms and image on the focal plane. This then serves as an image for the eyepiece. Since the focal length of the eyepiece at the focal length of the objective lens...

I need a book on telescopes which has got a physical approach to different types of it.if anyone knows a good book on it please suggest.

I'm trying to remember back to my undergrad physics days. Can anyone point me to a good textbook to compute the following? Given an infrared telescope with given specifications, such as the Infrared Astronomical Satellite and a star of defined intensity in the field of view at a specific point...

Hello everyone, I am brand new here in the PhysicsForum and this is my very first message. So it's apleasure to meet likeminded people sharing the same interest and probably also profession. The latter is also the reason why I finally registered in this forum and I sincerely hopethat I am given...

So if we become a Kardashev type II civilization, able to harvest all the energy and matter in the solar system what could we see through the massive telescopes that would be possible to construct? (say with a lens the size of Saturn). Could you get surface detail on extrasolar planets, for...

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...

Can anyone suggest a good book on telescopes

what is the difference between linear magnitude and angular magnitude

We are placing everyday more telescopes in satellites in orbit. Would't it be convenient to have some permanent telescopes placed on the moon's surface? I guess if we don't do that it's because that would be much more expensive than launching satellites? Are there no plans to place telescopes on...

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...

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...

I read that in terrestrial telescope there is an erecting lens whose function is to erect the inverted image formed by objective lens so that final image formed by eyepiece is also erect.there is no need of erecting lens in astronomical telescope because astronomical bodies are symmetrical in...

Astrophotography is a challenging hobby whose unique challenges and high upfront cost can turn many would be astrophotographers away. Instead of worrying about spending thousands of dollars, finding a good spot to image from, and dealing with setting up and tearing down equipment, another option...

What are the differences between these telescopes and which telescope will do more for our understanding of the universe? I know that ALMA is a series (66) radio telescopes, however, it also operates with optical telescopes. James Webb is an infrared telescope.

I am wondering why it is that we can look into Hubble's Deep Field and see galaxies 13.7 billion light years away, and 13.7 billion years ago, yet Big Bang theory tells us that 13.7 billion years ago all matter in the universe was very close together. Shouldn't we be seeing in HST that the...

I was wondering what kind of paint is used for radio telescopes, generally. In the case of the Green Bank Telescope, the idea is to get white at visible wavelengths, black at mid-infrared, and transparent at radio wavelengths. Titanium dioxide based paint was one substance cited on the...

Hello, I am opening this thread so as to discuss if possible what you believe is the science case of building a neutrino telescope. Being a fanatic in the field , I would like to hear opinions from whoever wants to say about whether it is important to build such a detector and why. Thank you!

Hi, I am interested in purchasing a telescope, although I am not very familiar with the parts and overall structure. introductory feedback, and recommendations would be much appreciated, and also I don't want a budget of $500 (preferably price range $350-$450).

Homework Statement What type of location for a telescope would be needed in order to oserve the emissions of the dying VY Canis Majoris? The material is rich in dust and molecules that would vaporise around hotter stars and emits infrared radiation. Homework Equations N/A The...

Homework Statement a) what is the angular size of the moon as viewed from the Earth's surface? b) The objective and eyepiece of a refracting telescope have focal lenghts 80cm and 2.0cm. What is the angular size of the moon as viewed though this telescope? mean radius of the moon-...

In my experience pictures from radio antennae are far less accurate than pictures from other areas of the EMR spectrum, why is this?

Why in telescopes and microscopes the ocular distance is such that it creates virtual images instead of real images?

Ref: http://www.physorg.com/news/2011-05-cosmic-rays-southern-sky-physics.html After finishing the article, I wondered, can't this principle be used to understand the universe better? Could we not make a muon telescope and learn some interesting things about emissions in space?

hi, if i travels at 0.99999c, i will measure time between andromeda and I (events happens in andromeda) shrink to only 0.00447 x 2 millions yrs compared with a person in rest on earth? Is this right, from t' = t x (1-v^2/c^2)^0.5 So if i travels to 0.99999999999999999999...c, then i can see...

What novel objects do you anticipate we will observe among the very first galaxies? Among the first stars?

will they ever make telescopes where the image is powerful enough to check out the surfaces of planets (real time) so we can see if there's life on them and also can see into other galaxys and maybe even pass through black holes and stuff? (not the actual telescope - i mean the image) we...

Binoculars vs Telescopes Which one would allow me to see farther into space: A 20x80 Astronomy Binocular or a 60x600 Telescope? Does an impression of depth with binoculars actually enhance the star-gazing experience? Sorry for the noob questions, but I'm about to buy my first...