I'm thinking about buying a telescope. I recently had LASIK and it refreshed my childhood obsession with the stars (since I can actually see them now.)

Anyone out there have, or know anything about them? I'd like to get something that gives me a great view of the moon. Maybe even a decent shot of mars or venus. Willing to spend a few hundred at least.

if you want to see venus or mars as anything other than a pale dot, you will probably need to spend upwards of a thousand, especialy on a decent mount so you can see details without having the scope constantly having slight shaking from moving it to keep the planet in view.

Sucks, alright well then I guess I can settle for a good view of the moon.

Pale dot? I don't think so. My telescope wasnt too expensive and I could see Mars, Venus, Jupiter, and Saturn pretty clearly. It's some Bushnell Telescope I think.

Don't buy one in too much of a hurry or you'll make a mistake. There's a lot of good advice on this topic out there. I'll try to rattle off what I can think of off the top of my head.

As an aside, your laser eye surgery (assuming it was done to correct short sightendess) will have had no effect on your ability to use a telescope. Your eyes were fine for that role before you fixed them :). All you'd have to do is turn the focus wheel on the eyepiece a little, compared to the focus setting someone with perfect vision would use.

First and foremost, think of a telescope as a kind of "light bucket". The wider the bucket, the more of the incoming starlight it will collect. Or in other words, the wider the main mirror/lens, the more light is collected and therefore the more detailed/bright/clear the image can be at the eyepiece. Don't think about telescopes much in terms of the magnification level they offer. A lot of crappy cheapo telescopes are advertised as being capable of OVER NINE THOUSAND TIMES MAGNIFICATION or the like, and that is generally complete cobblers. What you want is to get as wide a main lens/mirror as you can for your money (aside from other factors).

So the most important single attribute (there are other very important details, we'll come to that later) of the telescope is the diameter of its main mirror (or main lens, depending on what type of telescope it is).

The two common telescope varieties are "refracting" and "reflecting". Google can probably do a better job than me here, but put simply:

a refracting telescope has a large lens at the front end, and the eyepiece at the back end. Like this:

a reflecting telescope (also known as a Newtonian reflector after its inventor) has an open "front end", a curved mirror at the back end, and the eyepiece coming out the side, near the front (with a mirror held up inside the telescope at an angle to deflect the light from the main mirror to the eyepiece at the side). Like this:

At a given diameter of the main lens/mirror, a refracting telescope will collect slightly more light than a reflecting one, because of that mirror in the middle of the tube blocking a portion of the light. However reflecting telescopes tend to be cheaper to make, and they don't have to deal with any potential scattering of the different wavelengths/colours of light (lenses scatter different wavelengths of light a little, mirrors don't).

Patrick Moore's good old advice on this topic is to not buy a refracting telescope with less than a 3 inch main lens, and not buy a reflecting telescope with less than a 6 inch main mirror. Personally I'd say a 3in refractor is about equivalent to a 4.5in reflector. Anyhow I guess a telescope with a 3 inch main lens is more portable than one with a 4.5 or 6 inch main mirror.

A minor point, but a reflecting telescope can be more comfortable to use than a refracting one, simply because of the placing of the eyepiece. If, for e.g., your telescope were pointed directly upwards, to view the image in a refractor you'd have to bend down to look up through the bottom of the telescope.

Another, very important thing to consider is the quality of the mounting of the telescope. The telescope must be VERY stable on its stand, any vibration from a passing breeze or you nudging it or whatever will make the image you're looking at through the eyepiece shake like crazy. If you're looking at something with 100x magnification, any movement of the telescope will be magnified 100 times (possibly, it might be more complicated than that but you get the idea). You'll want an Equatorial-type mount rather than Alt-Azimuth, I'll let you google it to find out the differences

Speaking more generally, are you sure now is the right time to be getting a telescope? An all too common story is, "Man buys telescope. Man is mildly amused by telescope for a few days. Man then loses interest in telescope and stores it away in the attic because he doesn't know the sky well enough to know what to point the telescope at". It would probably be a good idea to find your way around the sky with the naked eye first, learn to spot the constellations well (they act as excellent "landmarks" to judge the positions of things by). Possibly get a pair of suitable binoculars as an intermediate step. Also try to foster a general interest in astronomy to help your chances of staying interested after the novelty value of the telescope wears off, to give yourself value for money.

Anyhow my typing digits are getting worn out, I'll probably return later to add more.

EDIT: Regarding price, I'd guess that in the UK you can probably get a fairly decent telescope for maybe £300, to be honest I'm out of touch with what's on the market right now though. A telescope at that price would let you, for example, see (assuming it's a telescope in the 3-6 inch range I'd expect in that price bracket) a very nice view of the surface of the moon... you'd be able to see Jupiter as a small disc with a couple of dark bands across it (along with the four Galilean moons)... and you'd be able to see Saturn's rings (plus one or two of its moons). Don't expect to see what the Hubble Space Telescope sees though!

Haha thanks A LOT! That's some great info! I don't expect to see distant nebulas or anything. Just a good look around our local neighborhood (meaning solar system, not my actual neighbors.) would suffice.

I will have to check into some of the things you mentioned, but I am more than welcoming to any more advice you can give!

This will only be true if the main lens or mirror is the aperture stop of the system, which for a telescope IS the case. But, you are correct in stating a larger aperture will give you a brighter image. Considering the application, you really want to collect as much light as possible.



The Newtonian telescope is only ONE TYPE of reflecting telescope, but it is one of the more common ones. A Maksutov is also another popular style. Also, light is REFLECTED from the mirror into the eyepiece, that's why they call it a reflecting telescope.



It is true that refracting telescopes suffer from something called chromatic (color) aberrations. The refractive index of materials (in this case, glass for visible imaging) is wavelength dependent. So, red, green, and blue will all be focused at different positions. This leads to a visible color spectrum on some images. This is highly dependent on the quality of the optics. It's not really scattering.



This is probably a good idea. You'd be surprised as to how well you can see constellations with a good binocular. Again, being the ******* that I am, it's not called a PAIR of binoculars. A binocular is a pair of telescopes, but a pair of binoculars is two binoculars.

You might also want to look into the quality of the eyepiece. The eyepiece can really make or break a telescope.

Fair cop guv. I'm not an expert, I just know a smattering and have too much time on my hands, resulting in the above long post. I was also trying to skip over a couple of things, like the fact that there are alternatives to the Newtonian reflector, to avoid getting too bogged down. Maksutov-Cassegrains are probably outside his price range. And I used the word "deflect" as a kludge to draw attention to the 90 degree angle and to try to avoid using the word "reflect" a confusingly high number of times.

I forgot to mention earlier, Focal ratio is something worth taking into account. It's the focal length* of the telescope divided by the diameter of the main lens/mirror. Low focal ratios, e.g. 5, are more suited for wide fields of view (useful when, for example, viewing open star clusters) while high focal ratios, e.g. 10, are more suited for detailed views of planets. Might as well google it for further explanation than that Any telescope you look at buying will have quoted stats for focal length and focal ratio.

*Focal length is the length of the light's path through the telescope from main mirror/lens to the point where it comes to a focus. In a simple telescope design like refractors and Newtonian reflectors, the focal length is kind of similar to the length of the telescope itself, which has an impact on the telescope's portability.

Oh, one other thing. There are telescopes out there with computerised GOTO mounts, which'll point the telescope at objects you want to look at without much user intervention. Apart from being ruled out due to being outside your price range, I think you're better off learning your way around the sky so that you can find things by yourself.

Oh, and if you'd be willing to consider binoculars, you'd probably want 7x50s (7x magnification, 50mm diameter main lenses) as these have a low enough weight to actually let you hold them up steadily for any amount of time (as opposed to something massive like 20x80s), they collect a decent amount of light, and would produce a good sized "exit pupil" (the width of the image coming out of the eyepiece is similar to the width of your pupil at night).

EDIT: This is well worth reading:
http://www.wwnorton.com/college/astronomy/astro21/sandt/startright.html

In fact that site in general has a lot of good stuff.
http://www.wwnorton.com/college/astronomy/astro21/sandt/backyard.html

Wow, thanks again! I think this has probably been the most informative thread I've ever started on this website hah!