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Amateur Astronomer Bruce Berger Talks About Telescopes, Part II (Video)
Bruce Berger is an IT
guy, but he's also an amateur astronomer who takes telescope selection and scope building extra-seriously. We ran a video interview with him yesterday. Today that interview continues, with more emphasis on telescope selection and purchasing. He mentions Orion, a telescope vendor he seems to respect, along with other sources for both new and used equipment. Which should you buy (or build): A reflector or a refractor telescope? Bruce talks about how you should make your selection based on what you want to view, your skill level, and how much time and/or money you have available.
Long time ago, before the age of CCD photography and GPS setup for telescopes, I used to have a 20" reflector. The tube was longer than the width of my truck :) It was a lot of fun, even though it was very difficult to setup. I even tried some photography....wait for it....with hyperexposed film. I loved the reflectors but ended up trading it for a 5" motorized SCT for the simplicity of operation. Maybe some day when I have time to stay up all night again, I will go back to reflector.
I've always said English was my second language. Had Romeo and Juliet been written in C, I might have understood it.
Rule of thumb: Planets=refractor. Deep sky=reflector.
Wow, if you have an unlimited budget to spend, it might be a good idea to have this nice Japanese refractor. But a reflector is still the best ratio of energy collected/dollars. And a nice 8 inch (200mm) F/4 can be a good deep sky telescope for a fifth of the price if not less.
And someone who doesn't get it.
An F4 reflector will suck at planetary imaging. You'll invest more in coma-correcting eyepieces/field flattening (you know, for photography) than if you've used a 105mm Achromatic (not even Apo) refractor.
And since planets are bright, you don't need a light-bucket, plus you can get a much longer focal length with a refractor.
Also, since you're looking through a much wider column of air at your target with a wide reflector, "seeing" is more of a problem than with a 105mm refractor. (which is plenty enough for looking at planets).
A telescope is an entire system, and the size of the aperture is only /one/ consideration.
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BMO
Planets are not all that bright, actually, by the time you've magnified them. I bought an 18" f/4 a couple of years ago, and I must say I'm really blown away by the planetary views. The extra aperture really brings the image to life because the colours are so much more vivid than they are in a little refractor. If the seeing's not so good I just stop it down to a 6".
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I've owned a few refractors and currently have an 8" dob (newt mounted on a simple alt/az base). With a small refractor (say under 102mm) it's easy to just pop out of the house and start observing. Fast refractors (like Orion's 80mm shorty) are great for scanning the deep sky and drinking in wide views of the milky way from a dark site. They set up fast and don't take up much room when stored or while in the car. My 8" newt is a completely different setup. It's heavy and bulky and takes up a ton of room in the car while transporting. In the winter it can take a couple of hours for the mirror to cool down to ambient temperature and provide stable views (on top of the 15 minutes it takes to get setup). That said, other than the narrower field of view, it shows much better on planets and most deep-sky objects than any sub $2,000 refractor is capable. In an ideal world, one would have both a small grab-and-go refractor (or possibly some 15x70 or 20x80 binoculars) for quick/casual viewing and a medium or large reflector for serious viewing.
I can't stress enough that the best telescope is one you're going to use. I've seen a few people spend a lump of cash on a shed-ornament.
Coming home after a long day at work and expecting to spend an hour setting up a german equatorial mount or wheeling out a heavy dobsonian will quickly kill your enthusiam.
Determining which scope is best for you involves checking out other people's gear at star parties or at a local astro club. Ask questions like "how often do you use this?" and "how long does it take to set up?" as well as "what can you see?". Remember that location is pretty important but it is not the be-all and end-all of astronomy. Dobson would routinely show people planets and deep sky objects from the middle of the light-polluted city with his constructed telescopes but you can buy a little grab and go scope of much smaller aperture and see much much more from a site with low light pollution.
Another mistake I see lots of people making (even telescope manufacturers!) is to pair a scope with a mount that cannot support it. You'll get a far better view through a small scope on a solid mount than with a large scope on an insufficiently robust mount.
Please don't drop a few hundred dollars on a shiny telescope hoping that you'll see wonders straight away. It's tempting to a lot of people and is a likely way to kill all your enthusiasm for a highly rewarding passtime when you realise you're spending more time fighting with the instrument than you are using it.
Most importantly, do not give one of those crappy National Geographic style scopes to a kid. Presenting astronomy as a frustrating experience will ruin it for them for a long time.
Find what works for you - a little research goes a long, long way.
Clear skies.