Telescopes Definition and 89 Threads

why do telescopes have long barrels? Binoculars use pairs of prisms to lengthen the light path between lenses, but why? What advantage does the lengthening the path of light have?

Hey guys, I was originally going to order the following telescope, but I found one at a local store, so if its as good or better, it would be easier to get it so I don't have to order. I was going to order this one: http://www.islandeyepiece.com/shopexd.asp?id=833 But found this one...

Looking over CSI's "zoom and enhance" silliness, are there telescopes that could show a recognizable reflection off a small object, even a good mirror, at a mile or so? What range limits are there for reflection using high-powered scopes?

Homework Statement A telescope has a mirror with a focal length of +3 meters and the distance from the mirror the the eyepiece is 3.5 meter. If the eyepiece is 3.5 meter. a. If the eye piece has a focal length of 50 cm, where would the image produced by the eyepiece be? Could the image be...

If a star 100 light years away from Earth exploded this very second, we would only see the explosion 100 years from now. If this is true, and if we pointed a telescope at that star right now itself, would we then be able to see it explode right away or would it still take us 100 years to see...

If it were possible to build a telescope that could see light from ~14 billion lightyears, would we be able to observe the Big Bang? And if so, would this be the case irrespective of the direction the telescope is pointing?

So, I just received my 3x barlow lens in the mail and let my scope sit outside for two hours to adjust..later I realize the humidity is 80-90% and my scope (6" dob) is literally dripping. Other than moving to Arizona, is there a practical solution to this problem?

"Bottom" limit of telescopes I know this is a very elementary question, but I was never quite able understand why there was a bottom limit to what telescopes could "see". For example, I have not quite been able to grasp why telescopes can only see in the radio, but are invisible to optical...

Where can one get a e-Documents/eBooks that will provide for the basic concepts, Technical guidelines to go about choosing Hobby Telescopes & general purpose Binoculars (construct differentiators and features that conceptually approach professional quality) but stays within the boundary...

How do space telescopes work? How do all of these space telescopes work with frequencies other than visible light? For example, the Spitzer Space Telescope launched by NASA works on the Infrared frequency...but how? We can't see anything but visible light, so how does it convert...

Alrighty. I've been interested in astronomy and other relative fields since I was a child, but due to my music commitments I've never had any 1'st-person experience in relation to utilizing a scope. My parents bought me a Celestron Powerseeker 675 back when I was a kid, but I only ever pointed...

in a refracting telescope, the lens's diameter is 1.02 m and its focal length is 19.4 m. how long must the telescope be to get an image, 40 times bigger? i would also like to get a link to a site explaining this kind of elementary optics.

As I was helping my teenage kids with their science homework, I began to wonder if and how Einsteins theories on time/space relationship would apply to someone who was using a telescope to view a far distant Red Giant going SuperNova. Would using a telescope to view such an event result in...

O.k., I'm not sure how to phrase this, but I'm going to try. If I'm confusing in my question, just ask for a clarification. I want to know how detecting the source (or direction) of an interstellar signal works? Specifically, a theoretical signal sent from an alien civilization at us. For...

Hi all, I want ask about any magazine related to telescopes & astronomy? like scientific american magazine.

Other than an engineering project, what could we look at with a 25 m+ telescopes? http://en.wikipedia.org/wiki/Thirty_Meter_Telesco"

so i am building a refractor telescope and i don't know what size to make the tube and what material to use for it? please telll me this is a huge % on my grade

Homework Statement I need to calculate the zero point of the telescope and camera i used. Homework Equations The Attempt at a Solution I have count rates of various points on the screen in a 19x19 pixel box of a standard star using the two filters V and R. I've used exposure...

Hi, I recently read about the exciting research and progress being made with lenses made from negative refractive index materials. In theory, these materials have no limit to their resolving power and so far experiments have shown they can image objects smaller than that possible using...

With physicists building big neutrino detectors like IceCube and Anteras astrophysicists where hoping for a completely new way of seeing the universe. However the first results for neutrino astronomy coming the old Super Kamiokande labs, and from around 1500 neutrino in the TeV range, the've...

My question concerns what deep field objects you can see by eye using a quality 8" or 10" Cassegrainian scope? I understand that you can get some nice photographs with long exposures, but what about just looking through the scope? Planets are a given, but what about spiral galaxies, as an...

We Are Trying To Design A Grinding/polishing Machine To Manufacture Concave Mirrors Upto 1.5 M Dia Does Anybody Have Any Plans For Construction

Being a light-hearted discussion! :smile: There are the neutrino telescopes, of which AMANDA is my favourite (though only Super-K has detected (imaged is too strong a term) any astronomical object ... yet). There are the gravitational wave detectors, of which LIGO gets all the attention...

Hi, Here's the question: a) There is a radio telescope that is 1000 feet in diameter. It is claimed that it can detect a signal that lays down on the entire surface of the Earth a power of only one picowatt. What power would be incident on the antenna in this case? It seems to me that...

I don't understand why these turbulent cells in the atmosphere tend to cause different problems in larger and smaller scale telescopes. anyone who can help me out?

Confused to what the theta represents in the theta = wavelength/D formula. Is it the same theta as you can find using trig if you know the distance and size of the object you're trying to see? And does anyone know a good site for astronomy formulas involving telescopes, my textbook isn't cutting...

Was wondering why reflecting telescopes (with a secondary mirror) do not have some kind of hole in the picture at the focus of the telescope. My guess would be that the obstruction is not near enough to the focus. Anyone know?

Hey Im looking to buy a fine quality telescope by either Meade or Celestron, a schimdt Cassegrain. I came across this one while I was browsing throught the Celestron website, http://www.celestron.com/prod_pgs/tel/nx8ise.htm it's really cheap in comparision to any other computerized schimdt...

Well I'm surely interested in astrophotography. Or maybe not. I really don't know -- to be completely honest. I am sure however, that i want to buy a telescope, and observe the far sides of this perpetually expanding, glorious universe of ours. So i won't be modest, and arrogantly demand help...

More research for scifi stories: What the "theoretical" limits on the size of a radio telescope (assuming great advances in manufacturing techniques and unlimited resources). I know the resolution is dependent on how far apart you place the individual components, so could you in theory have...

I would like to know if there are some internet based telescopes for the public which can be useful to watch objects that are below the horizon or when the weather is bad.

I've been stuck on this problem for a while now, and have tried it several different ways, but with no results. This leads me to believe that I'm missing something obvious or simply approaching it from the wrong direction. The moon subtends an angle of 0.5 degrees at the objective lens of a...

Neutrino astrophysics fans may find this recent paper interesting: APS Neutrino Study: Report of the Neutrino Astrophysics and Cosmology Working Group http://arxiv.org/abs/astro-ph/0412544 I took the liberty of pasting a couple quotes I found provacative Detection of relic neutrinos...

Lubos Motl post on his forum: ---quote--- David Goss pointed an article in New Scientist to me. http://www.newscientist.com/channel/fundamentals/mg18424781.400 Unfortunately I can't get the full version right now. But it seems that the article claims that someone has observed double...

Is it possible to determine the smallest angle that can be resolved with a telescope if the only information you're given is the telescope's aperture? If anyone can help me out I'd appreciate it.

Semi-ignorant question follows: Ok, the theoretical maximum observable universe is limited to a number light years slightly less than the age of the universe, but as we increase in speed, the universe flattens out, so, as we approach the speed of light, do we get to see more of the universe...

I've been thinking of getting a telescope. At first I was looking at the cheaper models that weren't too impresive but then I found the Knous 500. It's a 4.5" f5 telescope that comes with mount, tripod, RA motor with hand control, sight scope, polar scope, moon filters and two eye pieces for...

Hello there everyone... Lately I've been working on the idea to build my own telescope... now as the reflector telescopes are kinda hard to build (especially their mirrors ! ) I've decided to build a refractor telescope... What i am asking is : Do you have documents and website adresses or...

Let's get the new format with a somewhat general question. How many of you have built your own telescope? Give us some details. Did you do anything different or inovative with your design, or pretty much by the book?