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Telescope buying advice May 26, 2012

Posted by aquillam in Astronomy, MichiganAstro.
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One of the most common questions I get is “what telescope should I buy. ” Prices have come down significantly in recent years, so it’s time for an update. First though, I’ll reiterate one more time my old advice: consider binoculars. They’re easy to use, portable, affordable, and useful for lots of things besides astronomy. If you already have considered them, and you’ve decided that you really do want a telescope, read on.

Decide on a budget before you start. You can’t really spend less than $100 for a telescope plus the accessories, but there really is no upper limit, so decide how much you are willing to spend first. Don’t forget that there are likely to be accessories so be sure to include those in your budget. If your budget is under $200, you’ll probably need a few non-standard accessories, like a table. I’ve listed a few examples at the end.

The best thing to do is go someplace where you can look at the ‘scope before you buy it. What I’ve written here assumes you have that option. If not, you’ll have to rely on pictures and descriptions in catalogs or online. Check the return policy before ordering! Cloudynights.com has a lot of equipment reviews, but I recommend that you have some idea what you want to know about before going there or its likely to be pretty overwhelming.

The most important thing is to make sure it is something you will use.  If it is too heavy for you to set up by yourself, you’ll either need a helper, or a permanent mount with a building to protect the ‘scope. A 16″ Dobsonian is not going to fit in a compact car, or in a minivan with 3 kids. German Equatorial mounts have several pieces that have to be assembled if you try to travel with it, including a counterweight that can be heavy and awkward. If you want to do photography, you need a mount that can track. Computerized mounts can be nice, but they require some extra set up time, so they aren’t appropriate if you want to be able to grab the ‘scope for a quick look before bed.

One of the easiest ways to tell if the telescope is worth spending money on is to look at the mount. Most telescopes come with a tripod. If it is wobbly, or unstable, don’t get it. If it’s too light for the ‘scope, don’t get it (a good mount does not require a sandbag!) If it is stiff or hard to adjust, skip it. Unlike terrestrial observing, things in the sky move, so you want the mount to move too. If the mount will track, make sure the locks are snug enough that the telescope won’t move if bumped, but they do still allow the fine motion control to work smoothly. I have run across several Meade ‘scopes made for department and discount stores with the normal, excellent optics of Meade, but the tripods were so bad the ‘scopes were basically unusable.

The next thing to decide on is what type of ‘scope to get. In general, a wider telescope makes a brighter, clearer image. However, if you’re observing in light polluted skies, the ‘scope will also collect more of the background light and wash out deep sky objects.
– Refractors have only lenses so they are the traditional spyglass type. They never need adjusting, and most people find them very intuitive to use. However, wide refractors are also generally very long and heavy.
– Reflectors use mirrors, and sometimes also have lenses, usually called corrective optics.  Most of them require occasional minor adjustments.  They can be less intuitive to use, especially the Newtonian style which has the eyepiece coming out of the side. However, most people adapt fairly quickly, and reflectors are generally lighter and less expensive for the same width.
– As a general rule of thumb, refractors are better for observing planets, the Moon, and other solar system optics, and reflectors are better for deep sky objects such as nebulae.

In addition to making sure the telescope is something you will use and that the mount is good, you should also check out the telescope optics. The image should be clear, with no distortions near the edges. The image should not have extra colors, and objects should not have auras or be partly out of focus. The focuser should move smoothly and easily, but hold when you let go.

Good names include Celestron, Meade, Orion, Williams Optics, and Edmund Scientific. In general, anything made by these companies will be good ‘scopes as long as the mount is good. You may also find a good ‘scope made by another company, but watch out for anything under $500 from another company.

Some examples (prices are estimates based on manufacturer’s websites in May 2012)

A Celestron FirstScope, a book with charts like Nightwatch by Dickenson, and a small folding camp table make a nice starter set for under $100.

An Astroscan from Edmund Scientific plus the carrying case so you can travel with it will run you about $300. You’ll probably want a small folding camp table too, but the Astroscan comes with star charts to get you started.

If you want to get the classic refractor type, a 90 mm (3.5″) with a good mount should cost at least $300. Be skeptical of anything less than that.

A small, compact telescope called a spotting ‘scope is also very useful for terrestrial observations, like bird watching. They also make great zoom lenses for SLR cameras. A beautiful, compact APO refractor from Williams Optics with a tripod, diagonal, zoom eyepiece, and camera adapter will probably run you around $2500, but you’ll be able to take amazing photos and fit everything into a carry-on. These are also good deep-sky ‘scopes, despite being relatively small refractors. Orion and Celestron make much less expensive spotting ‘scopes. A Maksutov-Cassegrain spotting ‘scope from Orion with a camera-type tripod should run you about $500

A Newtonian telescope on an alt-az mount (short for altitude-azimuth) like a Dobsonian is very quick and easy to set up, so it makes an excellent grab-n-go ‘scope. These also tend to be no-frills ‘scopes, so you can get an 8″ scope for about $350 from Orion. Add the computer controlled base and it will cost you $600.

An 8″ Schmidt-Cassegrain is a classic amateur telescope, and is still reasonably easy for one person to set up and take down. Celestron began manufacturing these in the late 60s and you can still find them used with a mount and a couple eyepieces for around $800. If you want a new one, Celestron and Meade both make nice Schmidt-Cass ‘scopes for around $1000 for just the optical tube, $1500 for the tube and a German equatorial mount. Make it a computerized, motorized fork or arm mount, and it’ll run you about $2000. Add things like cooling fans and stabilizers to make it a really great astro-imaging system and you can quickly reach $4000 before you’ve invested in the camera!

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Comments»

1. Telescope Tune-Up Time | David Reneke | Space and Astronomy News - July 27, 2012

[…] Telescope buying advice (aquillam.wordpress.com) […]

2. Calvin Izumi - June 3, 2012

I’m still learning from you, as I’m trying to reach my goals. I absolutely love reading everything that is posted on your website.Keep the stories coming. I loved it!

3. Farm Animals » Blog Archive » Find The Appropriate Telescope For You Using These Tips - June 2, 2012

[…] } .imagecell a img { width:100px; border: 0; } Turn Left at Orion by Guy Consolmagno and Dan M DavisSideways Orion // 0) { //0==expires on browser close var cdate = new Date(); […]


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