How to Buy a Telescope November 19, 2008Posted by aquillam in Astronomy.
Tags: astronomy, telescope
I am frequently asked for advice on how to buy a telescope, especially by people starting out who “don’t want to spend to much.” So here it is, in a conveniently available space.
If you have the chance, try it out before you buy it.
Don’t forget a star chart.
Get a reflector – you get more aperture for your buck (aperature = width = light gathering ability.)
Plan to spend at least $400 or risk having lousy optics, or a mount that will drive you insane (take 2D20 damage to San for every attempt at using your $100 ‘scope)
Pay attention to weight and size. If you can’t carry it outside by yourself, it’ll probably become a really expensive door stop.
Pay attention to the mount. If you take a table-top model out to a field, you’ll need to bring a sturdy table too, which may negate the space and size saving of the table top mount.
Don’t forget eyepieces. You’ll want something relatively long (40 – 50 mm, wide fields of view, bright, low magnification), and a mid length (25 – 30 mm, still a good field of view, bright, and enough magnification to bring in a little detail.) Until you get to know you’re ‘scope and the sky, skip the short, high magnification eyepieces – they also cut out the amount of light that gets through, and can make an otherwise good ‘scope into something only suitable for the Moon. Also, the eyepiece(s) that come with the ‘scopes are usually not very good, so having one medium length eyepiece with good “eye relief” may also make the difference between a fun telescope and a doorstop.
Stay away from ‘scopes that are advetised as being great for kids. They are usually fragile, inflexible and plastic. The Edmund Scientific Astroscan is the exception to this, but it’s not cheap, and it’s not a toy (Mine once fell down a half flight of stairs, and 25 years latter it’s still my favorite ‘scope for travel)
And finally, consider getting a tripod and a nice pair of binoculars or a spotting scope – they’re highly portable and have lots of other uses, so you still have something worthwhile if you decide astronomy leaves you too sleep deprived. And if you love astonomy, they’ll always be a handy thing to keep by the door so you can run out and catch the space station. A good pair of 10×50 binocs with a tripod and a star chart should be less than $150.