Friday, September 14, 2012

Advice for First Time Telescope Buyers

If you are new to astronomy and contemplating the purchase of your first telescope, this page will help you to better understand what to look for in a telescope and what to expect from it. There are many telescopes aimed at beginning astronomers, and first time buyers are often overwhelmed by all the choices, brands, etc. This page will arm you with the basic information you will need to get off to a good start in astronomy.

The contents of this page applies to small to medium sized, beginner (or "first") telescopes. By small, I mean 2.4 inch (60mm) to roughly 3.5 inch (80 to 90mm) refractors, and 4.5 to 6 inch (100-150mm) reflectors . Telescopes in this beginner class typically sell for around $150 to $600. Quality starter telescopes are available from a number of manufacturers. The buyer should be aware that there are quite a few very poor quality telescopes in the marketplace; these are most often found in "department stores". It is hoped that the information on this page will help out prospective new astronomers and to advise them not to expect too much from a small telescope. 

First...BEFORE you buy a telescope!

Many experienced amateur astronomers will tell you that the best way to get into astronomy is to first learn some of the basic constellations, and then use a pair of binoculars to find your first astronomical objects. It is important to learn the basics of finding your way around the sky (you will need these skills to find objects using a telescope). Binoculars really can show quite a number of interesting sights in the night sky. A good pair of binoculars will often cost less than a telescope; in fact, if your budget only allows spending about $100, you might be better off buying a decent pair of binoculars and a good starter book rather than a telescope. Most experienced amateur astronomers agree that "jumping in" with a fancy expensive telescope without first learning the basics is not the best way to get involved. 

Astronomy is a fascinating hobby but it's not for everyone. If you spend $1000 on a fancy telescope and then later find you're not really into it, you will have wasted a considerable amount of money. Binoculars are a great way to get a taste of what backyard astronomy can offer. Another great way to start in astronomy is to visit a local astronomy club (most larger cities have some kind of club). Clubs often have loaner scopes, or at minimum, there will be members that will be happy to show you a number of telescopes. Binoculars can be a good first step, but they won't show any detail on the planets (and limited detail on the Moon). If you have a pair now, do try them out!

Ready for a telescope? Please read on!

Number One: Have Realistic Expectations!

DON'T EXPECT a small telescope to show images like those you may have seen in magazines. Those pictures are likely from the Hubble Space Telescope or some other large professional telescope. If you are expecting "video game" or "Hollywood" type images with amazing detail and vivid color, you will be in for a pretty big letdown.
What can you expect to see? Below we will describe what you might reasonably expect to see with small telescope:
  • The Moon: The Moon is a target that will show tremendous detail in virtually any telescope. Even a telescope as small as 2.4 inches (60mm) will reveal a wealth of detail. You'll be able to see craters, mountains, "seas", and a number of other fine details. The Moon rarely disappoints a first time viewer! Contrary to popular belief, Full Moon is not the ideal time to look at the Moon with a telescope; first (and last) quarter is the best time. During this phase the Moon's details will be lit from an angle and this allows much more detail to be seen!
  • Mercury: Mercury is hard to see because it never gets far enough away from the Sun to be easily visible. If you do manage to locate it in a telescope, it will appear very small and at best you will only see the phase. Surface detail is only barely detectable by the most experienced astronomers using world class equipment under ideal conditions.
  • Venus: Venus is also is also fairly close to the Sun and visible only during the evening or morning skies, however it is easy to spot as it is very bright. When you do see it expect only to see its phase in a telescope; no surface detail will be seen since the planet's surface is permanently hidden by a thick, white atmosphere.
  • Mars: Mars is easily seen in a small telescope, but often a big disappointment to first time viewers. It only reveals subtle detail when it is close to Earth (and this occurs for a period of about 2 months every few years). When Mars is close to Earth, you might see a white polar cap, and perhaps some surface markings. The biggest problem with Mars is that it's a small planet. Even at high powers in a large telescope Mars at best looks about the same size as a tennis ball viewed (with the naked eye) from about ten feet!
  • Jupiter: Jupiter is the planet that consistently shows the most detail in amateur telescopes. However, even at high magnification Jupiter will only look about the size of some of the medium sized craters on the Moon. On any given night you'd be able to see a few cloud bands, the 4 Galilean Moons, and maybe the Great Red Spot. Jupiter is easy to find (when visible) as it is among the brightest objects in the night sky.
  • Saturn: Saturn will show its glorious rings, but the planet will not look too large even at magnification of around 100 power. Keen eyed people (with good viewing conditions) might also spot some subtle cloud bands. Saturn's largest moon Titan will also be visible nearby but only as a moderately bright dot.
  • Uranus: You'll need to know exactly where to look to find Uranus (it is only barely visible to the naked eye under dark skies). At best it will look like a small green dot in the telescope. Even in large telescopes Uranus shows only as a small, featureless disk!
  • Neptune: Like Uranus, you'll need to know exactly where to look (it's too faint to see with the naked eye), and at best Neptune will look like a somewhat dim small blue dot (it won't really look any different than a star). No amateur scope can see any detail on Neptune.
  • Pluto: Pluto is out of the question for a small telescope; it generally requires an experienced observer using at least an 8 inch telescope (in a dark sky with a highly detailed finder chart) just to see it as a very faint dot!
  • The Sun: You can look at the Sun with a small telescope, however you MUST USE A SPECIAL FILTER FOR OBSERVING THE SUN WITH ANY TELESCOPE. Failure to do so will result in permanent eye damage and possible blindness. DO NOT attempt solar observation unless you are certain you have the correct special equipment AND you know proper procedures. Solar observation is safe if you adhere to proper procedures! You can see sunspots and solar "granulation". If in doubt about observing the Sun, have an experienced amateur astronomer with you prior to solar observing... your eyesight is at stake!
  • Stars: Stars stars will look brighter in a telescope but they will not look any larger. No amateur telescope has anything close to the power required to make a star look larger! They are simply too far away... The color of stars will be more easily visible in the telescope however.
  • Deep Sky Objects: In addition to planets and the Moon, there are a number of other objects within the reach of a small telescope. These are the so called "deep sky" objects. These include galaxies, star clusters, nebulae, and double stars. However, the quality of the view you will have on these kinds of objects depends to a very large degree on how much light pollution you have in your area (more on light pollution below). To locate most of these objects you'll have to use a star atlas (first you'll have to learn the basic constellations in order to find your way around the sky). Again, don't expect to see galaxies and nebulae like they appear in most magazine photos. Most galaxies and nebulae appear as "fuzzy patches of light" in small (and even large) telescopes. Star clusters and double stars are often quite beautiful and are good targets for small telescopes.
Credit and Source:
Joe Roberts

No comments: