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Buying a Telescope for Christmas

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Lots of cheap telescopes like this one - basically toys - go under the Christmas tree. This is not one I recommend!

It’s that time of year again. Cremated turkey, chimney fires and family rows: Christmas can go wrong.

One common mistake you can avoid, though, is killing a child’s budding astronomy interest with the wrong telescope.

Having bought scopes for my own daughter, run astronomy evenings at the local Cubs and done a fair bit of adult outreach too, I’ve got some idea what works and what doesn’t when it comes to telescopes for beginners. Here are some seasonal guidelines and recommendations based on those experiences.

So, what makes a telescope good for a beginner?

Here are six basic criteria to follow:

1)    Wide field of view

2)    Good finder

3)    Simple, stable mount

4)    Good optics

5)    A smooth focuser that takes 1.25” accessories

6)    Quality eyepieces and diagonal

If you meet these six criteria you won’t go wrong. Let’s briefly look at each in turn. For each one, I tell you what to look for and then give an explanation if you’re interested.

If you don’t have the time, just skip straight to my recommendations at the bottom.

1) Wide Field of View

Avoid telescopes with a focal length (see explanation below) over about 700mm. These scopes show a small area of sky and make finding things frustratingly hard for a beginner.

A telescope’s field of view is governed not by the diameter of its lens or mirror, but by its focal length. You’ll find this somewhere on the tube or box, like the plate on the side of this Tasco reflector which has a focal length of 900mm (‘F=900’). But note that some short telescopes actually have a long focal length because they use a folded optical design – check those numbers!

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This small refracting telescope has a short focal length and a wide field of view: great for a beginner!

This Vixen refractor has a long focal length and is less ideal for a beginner.

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Beware: this little Celestron has a long focal length too, but a short tube because the optical path is folded. It’s a nice scope, but harder to use for a novice.

2) Good finder

Red dot finders are best for beginners because they are easy to align and use. Avoid optical finders with plastic brackets: they never keep their alignment and are highly frustrating to use.

If you’ve never used a telescope you will be amazed at how hard it is to find things with it, even easy, obvious things like the Moon. To help, most telescopes have a finder. Finders come in two types:

1)     Optical finders (like tiny telescopes with cross hairs).

2)     Red-Dot finders (RDFs) that project a red dot from an LED onto a window.

Both types need to be aligned with the telescope. Optical finders can be good, but cheap ones often aren’t. DSC_1107 - Copy DSC_1151

Bad basic finder (optical, with plastic bracket), good basic finder (red dot).

3) Simple, stable mount

A simple alt-azimuth mount (see explanation below), preferably with slow motion controls, on a good, lightweight tripod is ideal for a beginner. Aligning equatorial and GOTO mounts can be frustratingly hard.

Mounts come in three basic types:

·        Alt-Azimuth: you just move the scope up and down, left and right.

·        Equatorial: you align these with the pole star, after which they make it easier to track things as they move across the sky with the motion of the Earth (in theory).

·        GOTO: finds things for you and tracks them once found (again, in theory). Sounds great, but often really hard to get working for a novice.

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Good beginners’ mount (simple) on the left, bad beginners mount (complicated) on the right.

4) Good optics

To be sure of good optical quality, stick to major brands. Avoid scopes under 70mm aperture and toy telescopes.

Good optics are vital, but how can you tell if the optics are any good? This is hard to do in a shop and impossible online, so buy an established quality brand. The major manufacturers – Skywatcher, Celestron, Meade – are safer than some others, but even their smallest scopes can have optical issues. Don’t buy telescope toys – some have useless plastic lenses.

5) A smooth focuser that takes 1.25” accessories

The focuser should have a metal tube and an opening of at least 1.25” (not 0.965”).

The focuser is an important part of any telescope. The drawtube should be metal and the opening at the end should be 1.25” or 2” in diameter. Some scopes have plastic focusers and 0.965” openings – avoid these (see pic on right).

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Good focuser (metal, takes larger eyepieces) on left, bad focuser (plastic, only takes tiny eyepieces) on the right.

6) Quality eyepieces and diagonal

Look for quality eyepieces, with metal barrels and proper coatings, that give low to moderate magnifications.

Eyepieces should be metal bodied with proper glass lenses that have good (dark blue) coatings.

You might think that more magnification is better, but it’s not true. High magnifications give narrow, dim views, make things harder to find and show up every shake and wobble. Low to medium (10x to 70x) magnifications work best for beginners.

To work out magnification, just divide the focal length of the telescope by that of the eyepiece. For example, a telescope with 700mm focal length and an eyepiece of 10mm gives a magnification of 70x – a good higher power for a starter telescope.

So, a couple of eyepieces with focal lengths of around 25mm and 10mm are ideal, giving one low and one high(er) magnification. The lower magnification is good for star fields and larger deep sky objects; the higher power is better for the Moon and planets and smaller nebulae.

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Good basic eyepiece (metal barrel, large eye lens) on the left, bad basic eyepiece (plastic barrel, tiny uncoated eye-lens) on the right.

My Christmas Recommendation

That’s it for my six buyers’ guidelines.

Let’s get specific (at last, I hear you say!)

If you are serious about giving a usable telescope that will encourage a beginner to start exploring the night sky (rather than just giving them a useless toy), here is my suggestion. Similar scopes are available from other makes, but this is one you can put under the Christmas tree with confidence.

This is a complete set-up: telescope, mount, finder and accessories that meet all my criteria. It is easy to use and gives great views of most things, including the Moon, planets and star fields. It’s not cheap, but as I write you can pick one up for about £160.

Later on, it’s easy to start doing basic astrophotography and you can even use it for nature viewing/photography as well.

Skywatcher Startravel-80 or Startravel-102 (AZ3)

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This is a short-tube 80mm/400mm refractor with a red-dot finder on an Alt-Azimuth mount with slow-motion controls that comes bundled with quality accessories and that meets all my six criteria. The 102mm version is even better, but not much more expensive. I’d enjoy using either setup myself.

Other Recommended Options

On a tighter budget, I have heard good things about Celestron’s Travel Scope 70 (but absolutely not the Travel Scope 50, which has issues that I’ve described elsewhere on this site).

If you must have GOTO, I recommend Meade’s EXT80 (NOT the ETX90 which is a very different scope with a small field of view). But be prepared to learn how to align it yourself before you give it as a present.

Dobsonians (‘Dobs’) can be good for older children, perhaps those with a more serious interest from a previous smaller scope. Skywatcher’sSkylinerDobsonians (130mm, 150mm or 200mm) are all an excellent choice. The larger sizes are good too, but are harder to set up, so less ideal for a beginner.

Where should I buy?

Finally, in my opinion, where you buy is less important than making sure you buy the right thing. A specialist may offer good, impartial advice (but sadly not always). Buying from somewhere that gives no-quibble returns is a good idea, in case there’s a problem (any telescope should easily give good clear images. If not, send it back!)

Merry Christmas 2017 from ScopeViews!

 

 

 

 

 

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