Telescope 101 and a little moreApr 18 '03 Write an essay on this topic.
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The Bottom Line Take your time, invest more in eyepieces then your first scope, and get a good pair of binoculars first
I consider myself a beginner, but people who know me consider me way in deep. So here's my little Telescope 101, I hope you learn something from it. I went into astronomy backwards, and by doing this, you can spend a lot of money the wrong way. Some facts to know about Telescopes: Apeture - is the diameter of the telescope. The bigger, the better, but not always. Beginner scopes start around 76mm (3 inches) and go all the way up to 12 inches, and then ususally home made telescopes go way beyond that into the 23 inch zones. Focal Length - its the length of the telescope basically. The bigger the focal length, the more power you'll get. Powerful scopes generally range in the 1000mm or larger range. This is basically all you need to know (right now) except for maybe the magnification. Let's say your Apeture is 250mm and your focal length is 1250mm. To figure out the power of your telescope, your eyepiece will be the key factor. Say I'm using a 12.5mm eyepiece. 1250 / 12.5 = 100x. That means using a 12.5mm eyepiece, you'll get 100x closer to the object I'm looking at. Depending on the scope, it will be plenty of power until you actually look into the eyepiece. 160x power on a 3" reflector scope and 160x power on a 10" reflector is very different. A Few things to know. When you think about getting a scope for the first time, don't just go out and buy it because its $200 or less and it says that it's powerful. Save yourself some money and get a pair of binoculars. I got a pair of binoculars 5 years after my first scope, and I would've been much better off with binoculars then the telescope, hands down. Binocular's price range are very reasonable for what you get and can cost less than $100. Plus you'll be able to use them during the day time. I recommend getting a 50mm apeture lens. You can find this out by looking at them, for example. 7x34, 8x50, 12x50. The first number is the power (how much closer you will be to the object.) The second number is the apeture of the lens. The bigger the lens, the larger field of view, meaning you'll be able to see a larger area. For astronomy, a larger field of view is required more, because when you look at a star through binoculars or a telescope, it will still look like a point like you see with the naked eye. Why? Because stars are SOOOOOOO FAR AWAY! But, you will be able to see A LOT more through binoculars or telescopes that you CAN'T see with the naked eye. High powers are used mostly for plantary viewing, and to honest, you won't see details like you will in pictures in books and magazines, or even on the net. Most of those are taken from the hubble, where it's past our atmosphere, and has optimial viewing conditions. You might have think I would've forgotten, but, some people take pictures from land, and they have colors and show great detail, this is true, but they are taken longer exposures, digital enhancements, etc, therefore, they are able to get "better views" however, if you were to look into their eyepiece, there's no way they would've seen that detail that extreme. The higher the power, generally you are pushing your scopes optics to the limits. Scopes will give you a "max power." You can go beyond the max power, but generally around, or past the max power, you will lose detail depending on the sky conditions, etc. http://www.celestron.com/tb-trms.htm -- Here's a great link to Celestron's website, where they show the differences you will seen in different apeture telescopes. However, it's not all that accurate. You will notice big differences between the two sides, but they seem to make it a little more dramatic. Of course your answer is "Get the biggest scope I can afford!" But thats not generally true. The bigger the apeture, the more light you gather, giving greater details, yes, but sucking in more light pollution. In my area, its very difficult because we have street lights all over the place and you can see the hazy glow around you. This will effect your views as well. You need it to be dark and a stable atmosphere, no matter what size your telescope to get the best views possible. I do however, still go with the "bigger the better" factor, because when you have a 3" scope lets say, I want to know what I'd get out of the next size, etc. Pyshical size and weight is a big consideration when buying a scope. My 3" scope, which had a big tripod and was somewhat big in itself, is considered easy to most, but it took a long time to set up the tripod with all the screws and get it setup, where, my 10" scope, which is like 20 times the size, gets done in two easy steps, however, the 10" scope weighs about 50 more pounds easy. Optics are everything. Eyepiece optics are the most important. Generally all scopes come with a few pieces, depending on the scope, depends on the eyepieces you get. Generally in cheaper scopes, you'll get cheap eyepieces to get you started. Eyepieces will be the heaviest expense, but will last forever if cared for properly, and can be used on any scope you have, or ever get. There are three typical sizes. .976, 1.24, and 2 inch eyepieces. the 1.24 are the standard size, some higher end or bigger scopes use 2 inch eyepieces. I would personally stay away from .976 sized eyepieces since they are basically worthless, and don't sell many types in this size. Basically make sure you scope accepts 1.24 eyepieces and your good to go. Eyepieces can range from $10-$400. Generally, plossl eyepieces (the best type of eyepiece for your money) are from $35-$60. So be prepared to spend money on eyepieces. I personally like 25mm, 12.5mm, and a 9mm. This is a good range to start with. By adding a barlow lens, you can effectively double the power of your existing eyepieces without losing too much quality. I personally feel the barlow lens should be the first eyepiece you get yourself when adding to your collection (assuming you have one or two regular eyepieces already). I would also make it the best you can possibly afford since when you start "getting into using your scope," you may purchase some really nice eyepieces, but when inserting them into a cheap barlow, it will effect the view of the eyepiece... Now, picking a scope itself can be crazy. They have EQ mounts, that track objects, goto scopes that will track objects automagically, alt/zth mounts that are basically point and shoot mounts. The honest answer is to learn the sky first. Look at star charts, get computer software to view realtime charts (I prefer skymap pro). Now, in the mount you choose, will boost your price way up, and sometimes the scopes themselves aren't as good because it makes up for the price of the mount. EQ mounts can be motorized, but beginner scopes, they aren't. My first mount was a EQ mount and I rarely used its features as it wasn't all that accurate. I used to just point and shoot it, so my next scope was a Dobsonian mount, which is point and shoot also. Gotos offer automagically find objects, but what are you really learning if you not even quiet sure what your looking at in the first place. Dobsonian telescopes offer large apeture along with cheap prices and easy setup. A 4.5" or an 8" scope (considered big) can be very cheap, almost as cheap as a beginner 3" scope with a EQ mount. Its a big decision depending if you have kids, etc. You have to have patience when finding objects. I know that when people are around me, I wind up by myself after a few hours because no one wants to wait around for stuff I'm looking for and get bored. These people may prefer a goto scope. Personally, I would like one of these, and one day I may get one, but at the price, I'd rather not, plus I'll know the sky pretty well before that. Reflecters, Refracters, Schmit Cassgrains, what!? these are just different ways gather light into the eyepiece. Reflecters are the simplest way to do it using two mirrors, the others are great also since they have smaller designs. I've been using reflecters so far, so I'm happy with those for now, plus they are cheaper in price than your other types, but they are a bit more bulkier. Look around, take your time, and get a pair of binoculars in the meantime while your still looking. Good luck, and I hope this helped a little bit...  |
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