Telescope Definition and 517 Threads

Hi When I was a kid, the largest telescope was Mt Palomar, a little over 5 meter diameter mirror. In spite of its large size, I always read that stars appeared as points of light through the scope if it were used visually, i.e. stars are too small and too distant to appear as disks. However...

Hi guys! I am planning to buy a telescope for a descent price. You see I'm totally amature and buying this telescope would be my first telescope itself. I sure have observed the night sky with binoculars and home made kinda simple telescopes but now I want to switch to something better. So...

Hello! I recently purchased a basic 6-inch Equatorial Reflector telescope. I bought it because I loved doing astronomy with large binoculars, and I assumed the next step was a small reflector telescope. However, I find myself barely using the new scope because the bulky Equatorial mount is...

So, I have a relatively small (6") Orion Dobsonian with a 25mm and 7.5mm Plossl eyepieces and live in a somewhat light polluted area. Because of this, I am considering purchasing an eyepiece filter to reduce light pollution and enhance nebula/planetary viewing. I was wondering how this would...

studying for exam- telescope problem (help!) Homework Statement What diameter optical telescope on the Earth would you need to resolve a lunar lander 3 m across on the surface of the moon 3.8e8m away? Homework Equations The Attempt at a Solution the only thing I can think of is...

I am wondering if I can have a good telescope recommended to me, I am deeply interested in astronomy and astrophysics and would like to be able to view astrophysical phenomena and objects on my own. Even if you can't recommend a good telescope, could you please reference a guide or something for...

Hey guys, I am really stuck on my homework review and really require help! Someone please help ! :( Homework Statement Question 1: A telescope has a focal length of 18m. If the suns diameter is about 1.39 x 10^9m and its distance from Earth is 1.49 x 10^11, how large is the telescopes image...

A while back, I posted here asking for telescope recommendations. After many members advised getting a dob, http://www.skywatcherusa.com/8-dobsonian-telescope-s11700.html" is what I went with. I love this scope. Seems very well put together and can capture some pretty amazing sights. One...

I'm a freshmen in college (currently undecided on my major) and am seriously considering an undergrad in physics with the intention of going to graduate school for astronomy. But before I get serious about it, and with Christmas on the way, I want to get a decent telescope. I'd say my possible...

Homework Statement I need to build a telescope from two magnifying lens, one is 2x the other is 5x. First I need to give the total magnification possible, state which lens to use as the objective and finally to state the length of the telescope. Homework Equations l Ml = Fo/Fe total...

hi, i don't understand why the 2 converging lens telescope's magnification is given by M = f_o / f_e where f_o = focal length of objective, and f_e = focal length of eyepiece... issn't M = image distance / object distance... in the case of a infinity object, the image is also infinity...

Hello! I'm not sure if this is the right section but it seems the best one for this question. I've been looking to buy a telescope just for fun and I'm surprised with just how many different options are available out there. I'm looking for something that's good for beginners since I've never...

Can I see anything other than the planets with a 4" telescope? I saw Jupiter (and four of its moons), Neptune, Mars and Venus but they were all really tiny so I was wondering if the planets are so tiny does that mean I wouldn't be able to see any of the other objects, like galaxies and nebulae...

Is anyone here familiar (more or less) with the new type of telescope called IACT, Imaging Air Cherenkov Telescope. Apparently TeV gammarays come to us from Active Galactic Nuclei (AGN) which are massive accreting black holes. Individual TeV photons leave blue or UV trails in the atmosphere...

Publicity often says that a new telescope can detect a candle across the Atlantic, etc. Well, a candlepower is defined as 1/683 Watts at 540 X 10^9Hz. This gives photon energy at 2.2 eV. One candlepower produces 4.2 x 10^15 photons/s radiated isotropically. At 3,000km the area of the...

Well I've decided to buy my first telescope and I've been searching craigslist for 'em. My price range is ~$200 and have so far found some (seemingly) good scopes. I've so far narrowed it down to three scopes, and I was wondering what you all thought about them. The scopes (all listed in...

I highly theoretical question, hope you guys can help. Say I have a telescope orbiting Earth at 100km, and say on the ground I have a mirror (of about 2x2m). Could the telescope see itself through the mirror (i.e look down to earth, zoom in plenty and see itself looking down). Thanks...

http://arxiv.org/PS_cache/arxiv/pdf/0908/0908.2696v1.pdf Abstract. Several early spyglasses are depicted in five paintings by Jan Brueghel the Elder completed between 1608 and 1625, as he was court painter of Archduke Albert VII of Habsburg. An optical tube that appears in the Extensive...

Planning is underway for the new super giant Magellan Telescope -- it will be the largest mirror ever on ground based telescopes, according to the link. http://www.gmto.org/

I have never owned a telescope before (only 20x80 binoculars) and I am looking to buy one now. I have 600 dollars to spend so i went and picked out what I THINK is a good good one for the price, however I'm not sure. So can any of you telescope experts out there take a look over this one? Also...

Hi I'm legally blind, so I own a small telescope that I use to see the board at school and stuff. On the front of it are these specifications: 6x16 0,25m-infinity 175/1000m 10degrees What do they mean? Thanks for your time.

I've searched for other topics about this on the forum, and the general advice seems to be that I should first try looking through telescopes at an astronomy club, talk to other amateurs, and buy binoculars to get familiar with the sky before I buy a telescope. There aren't any astronomy clubs...

So I just got my dads old telescope out, cleaned it, and installed new motors and cleaned the primary and secondary mirrors, and it's ready for use! It's a reflector with a 4-3/8" primary mirror, and I wonder: what can I see with this thing (besides the moon, obviously)? I know this is a super...

Homework Statement The Hubble Space Telescope is poered by two solar panels as shown. The body of the telescope has a mass of 11 Mg and a radii of gyration kx = 1.64m and ky = 3.85m, whereas the solar panels can be considered as thin plates, eac having a mass of 54 kg. due to an internal...

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.

I'm putting together the Itty Bitty Radio Telescope. In the instructions (see: http://www.aoc.nrao.edu/epo/teachers/ittybitty/procedure.html), it says to use a .1Mhz RF Choke. I have been unable to locate this particular frequency, as the only one I have been able to locate has been a 1kHz RF...

Greetings- I'm new to PF, but I just wanted to ask about telescopes. I'm new to astronomy, and I am looking to buy a new telescope for under $400. I mainly have been doing astronomy with binoculars (16x50), and I believe that I want a telescope with a relatively wide viewing field and high...

Able to industry 6inch reflector telescope,but I found that the image of the edges of the mini-optical example, if I looked at the moon I saw three Oqmra This note I did not use the eyepiece My question is: Will this form reflector when not using the eyepiece? Thank you very much

It fell halfway over, denting my metal garbage can lid. The finderscope came off but I could easily reattach it. I can see light and blur now...what should I do?? I don't want to just open it up without knowing what I'm looking for. Thank you!

Minimum Resolution Angle Problem Homework Statement The radio telescope at Arecibo, Puerto Rico, has a reflecting spherical bowl of 295 m diameter. Radio signals can be received and emitted at various frequencies with appropriate antennae at the focal point of the reflecting bowl. At a...

how can i make a telescope eyepiece please help me !

I have a Bushnell 100mm Mak Cassegrain telescope. When viewing Saturn with my 32mm eyepiece I can see it but I can't differentiate between the rings. When I use a 4, 6, or 9mm eyepiece, the image jumps so much I give up. Why is that and what can I do? Thank you so much. penny

hello, I found a concave mirror telescope in my town I think that it is very good for making Newton telescope Estimated length of 20 cm I will make a telescope , but I have a problem , I do not know the place of the focus and the place of secondery mirror; after focus or before...

Homework Statement Your telescope has a 700 mm focal-length objective and a 28 mm focal-length eyepiece. a) What angle (in degrees) does the image of the moon subtend, when you look at it through your telescope? b) Suppose you decide to take a photograph of the moon using your telescope...

Arccording to Nasa, the Kepler telescope will be working for 3.5 years in orbit and during that time it will observe about 100000 stars looking for exoplanets. Howcome it can finish for that workload?

I want to make an astronomical telescope, can anybody help. I need specifications for the lenses.

[b]1. For a Lab I have set up a "galilean telescope" where the objective lens a convex lens with focal length about 20 cm (F) and a biconcave lens of unknown focal length. I placed the biconcave lens at about 15 cm away from the convex lens as the ocular (so closer than the focal point) and then...

What is a Hubble Space Telescope and how does it work?

Hello, I have a question regarding a Cassegrain style telescope (or any other "obscured" type telescope, for that matter). Can someone explain (in detail) why the small secondary mirror out in front of the large primary mirror does not cause some sort of a "blind spot" in the center if we...

Hi, I have just recently gotten a 8 inch dobsonian telescope. I have two lenses, a 9mm and a 30mm. I really enjoy going out and seeing the sky and I have a few questions to make my outings a little more successful. The way I focus the telescope is my adjusting how far out/in the eyepiece...

Im a Physics student at UNC-Charlotte. I just got my first telescope and I already have a problem. I can pinpoint a star and see it but it looks the same size as it does to the naked eye. I changed eyepieces and everything. Still just a tiny little dot. Does anyone know what could be wrong...

Which are the top telescopes producers ? i want names of company

Hi there, Could somebody explain how illumination - by which I mean flux per unit area - depends on the mirror diameter of a telescope and/or its focal length? Is this different for point objects like stars and for extended objects like nebulae? Thanks in advance, Nick :-)

Homework Statement An earth-based telescope with a mirror of diameter 2.4 m can record the im- age of a faint star in 1 hour. A telescope placed in space (above the atmosphere) has a mirror of the same focal length as that of the earth-based instrument, but its diameter is 1.2 m...

Problem: Centaurus A is 15 million light years away and a radio telescope can resolve structures of 1s of arc across. Show that the Structure is 75 light years across. Please Help!

Since i heard/researched about this Planet X (Nibiru), 2012 (end of days), Mayans (Sumerian), Annnunaki (aliens), revelations (bible) and all that, I want to start to look into our heavens! So, i wanted a good telescope that can see to at least pluto... Anyway, what does everyone think...

Hey all, I've been interested in the stars all my life and I know a bit about astrophysics from booklearning and what's been taught in school and whoud one day like to make a career out of it but I've never actually used a telescope before. A few weeks ago my parents saw me looking at some...

http://en.wikipedia.org/wiki/Hans_Lippershey I read an article in Astronomy magazine that described how Lippershey tried to get a patent for the first telescope (Greek tele = 'far' and skopein = 'to look or see') in September-October 1608. Lippershey’s telescope could magnify a whopping...

2 or 3 years ago we bought my father a telescope for his brithday, and ever since it has been a piece of 'art' in my house. I thought i'd put it to use, i have an interest in astronomy and now i really want to learn how to use this. the telescope is a Bushnell 675x5" Reflector Telescope...

Is a radio telescope less sensitive on the galactic plane? If so, why? /San