If you've toyed with the idea of buying a telescope, and want to get something decent, but don't want to drop big dollars on a computerised hyper-scope or dedicate a large chunk of your life to the obscure rituals of the from-scratch telescope builder, an Astroscan remains a pretty darn brilliant introduction to the hobby.

On the down side, Newtonians tend to suffer from "coma", where things that aren't in the middle of the field of view are fuzzy. The Astroscan has a mild dose of this problem, but it's quite acceptable at this price point.

Still and all, though - you can do it. And you can use the Astroscan as a daytime telephoto lens, too; elegant it ain't, but something in the order of 2000mm of 35mm-equivalent telephoto power is nothing to sneeze at.

A screw through the middle of the base lets you lock the Astroscan down onto it, like this, for transport or storage. Or for those times when you're quite sure you only want to look straight up.

For instance, there's the much younger, and somewhat cheaper, Bushnell Voyager model 78-2010. Check it out.

A good telescope brightens up nebulae and galaxies and comets so that you can see them, without necessarily needing to make them a whole lot bigger.

When not starring in large books or devising laws of motion, Isaac Newton spent a couple of lazy afternoons devising a new kind of telescope - the reflector. The basic kind of reflector telescope is still called a Newtonian, and that's what the Astroscan is.

One of the strap screws does double duty; it allows you to affix this basic bent-aluminium peep-sight to the telescope. You don't really need a sight at all if you're using a wide-view eyepiece and have some basic star-spotting skill, but it's handy for higher magnification. If you find yourself using the sight a lot, upgrading to a Rigel Quikfinder or similar more sophisticated no-magnification finder might be a good idea.

The FunScope makes the Astroscan look big, and might be a good option if you're buying for a kid, but Orion's more expensive and less cute StarBlast seems to be more highly recommended.

This is irrelevant for Astroscan users, though, because there's no motor-drive option for the Astroscan; you need a motor drive that synchronises the telescope movement to the rotation of the earth if you want to do long exposure astrophotography without creating an artistic but uninformative image in which the stars turn into lots of concentric circles.

If you like ten-dollar words, you can call this a "ball type cast aluminium altazimuth mount". The important thing about it is the complete freedom of movement it gives - including the freedom to turn the telescope around its long axis, to point the eyepiece in whatever direction suits you while keeping the 'scope's aim the same.

That $US50 "Professional Telescope" you see on sale on eBay (or at a department store for $US75 or more) will not pass this first test. Actually, you can spend a fair bit more than this and still end up with a really awful telescope.

The planets are easy to view in light-polluted skies, too, though an Astroscan has a hard time resolving them as more than featureless circles if you don't get an eyepiece that pushes its magnification hard.

The angular size of the moon, for instance, is about half a degree (30 arc minutes). It may look big, especially when it's close to the horizon, but the tip of your little finger at arm's length should cover it with plenty of room to spare.

On the plus side, a cheapo telescope is virtually certain to be a "terrestrial" type, which'll show you things the right way up. "Astronomical" telescopes (including the Astroscan) normally show things upside down, because that's the simplest way to build the optics; it minimises loss of light and image quality. You have to add an "erector" to the eyepiece to flip the image. Naturally, Edmund stock an erector for the Astroscan, though the telescope's standard eyepiece mount will accept various others.

It's generally agreed that the Astroscan, despite its age, is a better piece of gear than the black Bushnell.

The eyepiece tube's protruding into the barrel at the top left in this picture; the back of the angled mirror's visible in the middle.

A Newtonian reflector telescope is a tube with two mirrors in it. The main, curved mirror is at the bottom of the tube; light comes down the tube, hits that mirror and is reflected back up the tube, towards the second mirror. That one's smaller, flat, and angled at 45 degrees; it reflects the light out at right angles into an eyepiece connected to the side of the telescope.

[UPDATE: This review is several years old now; I think most Astroscan packages are now a little more expensive.]

And, of course, Edmund also sell a dedicated Astroscan tripod, along with a bunch of other accessories for the 'scope.

The wide-angle lens I'm using for this shot makes the main mirror look further away than it really is. In the main mirror, you can see the reflection of the angled mirror, which in turn is reflecting a view of the red plastic cap that's plugged into the eyepiece tube.

The other side of the card tells you about latex allergies, which is presumably how the eyecup is going to kill you.

If you live in the USA, you can buy an Astroscan from Edmund directly. It'll cost you $US199 plus delivery for the basic package.

Edmund Scientific telescopeAstroscan

Apart from the above-displayed hardware, you get an excellent Using Your Astroscan guide, which suffers not at all for not having been revised since 1979. Today's telescopes don't usually have a bikini girl magnification example on page 12 of the manual, but I ain't complainin'.

There are also onshipping services that send packages from US dealers to various other countries, including Australia - see MyUS and HopShopGo, for instance (this is not a recommendation of these particular onshippers - they're just the first that came up in a search).

You can, of course, view the moon even if you live in Las Vegas; the moon's lit by direct sunlight, so it can drown out any amount of light pollution. 30X magnification is quite enough to make the moon look big - getting on for the size of a basketball held at arm's length. The Astroscan with its stock eyepieces is a great moon-viewing telescope.

Edmund's sibling site Ward's Natural Science does ship outside the USA, and will even do so for a tolerable price after a certain amount of back-and-forth, according to one of my readers.

Edmund ScientificAstroscantelescopereview

If you want to ditch the base altogether, this strap (which screws into sturdy sockets on either side of the Astroscan's barrel) lets you do it.

(There is, of course, the sun. You can view the sun with an Astroscan, if you buy or rig a viewing screen. Peering through the eyepiece at the sun is an express ticket to monocular vision.)

The strap is, intentionally, rather short. You can use it to sling the 'scope over your shoulder for carrying, and you can also slip it over your head and hang the 'scope from it, to help you keep the view steady as you cradle the Astroscan in your arms. This way of supporting the Astroscan won't let you use a lot of magnification, but with a wide angle eyepiece it works OK.

Even if your exposure is only a few seconds, though (figuring out exactly how much you can get away with can be a little complex), it'll still pull more light and colour out of the scene than your miserable eyes can manage. With the naked eye, nothing viewed through any amateur telescope will show any colour to speak of; with a camera, you can bring it out.

VintageEdmund Scientific telescope

When you're not using your Astroscan, you plug a big push-in lens cap into the business end, and there's also a plastic cap that replaces the eyepiece - I neglected to put that in place for the above picture.

You can attach cameras to all proper telescopes, and the Astroscan's no exception. Edmund sell an "eyepiece projection" camera adapter for it; eyepiece projection points a camera at a telescope eyepiece, and lets you strap on regular point-and-shoot digicams, as well as SLRs.

And a basic telescope should be portable. If you live in a big city, light pollution will make a lot of astronometric exertions futile. But if your telescope fits in a backpack, you can take it any darn place.

You can still pull a lot more detail out of the sky with a camera than you can with your naked eye, though, even if the lack of a motor drive restricts you to relatively short exposures. The earth rotates 15 degrees per hour, which makes stars fairly zip across a magnified field of view, when you're looking at stuff close to the celestial equator. The Astroscan's widest field of view is about three degrees - this makes it a "wide field" telescope, between the usual field of view of telescopes and binoculars. An equatorial star will cross three degrees in 12 minutes; the more magnification you use, the faster things will seem to move.

The Bushnell Astroscan-alike doesn't stink, but it's got a spherical main mirror rather than the Astroscan's parabolic mirror. Spherical mirrors aren't as good; they have aberration problems, so the Bushnell will never focus quite as well as the Astroscan.

Like all proper telescopes, the Astroscan can accept a variety of different eyepieces. You slide them into a simple friction-fit tube (of standard 1.25 inch diameter), and the focus mechanism moves the tube in and out. The Astroscan's focuser is not very high-tech; it's just a rubber roller pushing against the eyepiece tube.

If you live in the USA, you can buy an Astroscan from Edmund directly. It'll cost you $US199 plus delivery for the basic package.

Edmund scientific telescopereview

Even a crummy telescope may be acceptable if all you want is to invade the privacy of the people in the apartment building across the street, but even that may be beyond the capabilities of a department store 'scope.

Edmund scientific telescopemanual

In theory, the Astroscan's good for about 200X magnification for night-time use, though its simple aiming mechanism and less-than-totally-perfect main mirror mean you really ought to consider a more expensive 'scope if you intend to go much above 100X. Edmund recommend you not try higher than 35X, simply because of the aiming problem.

Edmund scientific telescopefor sale

There are also onshipping services that send packages from US dealers to various other countries, including Australia - see MyUS and HopShopGo, for instance (this is not a recommendation of these particular onshippers - they're just the first that came up in a search).

Camera adapters are a considerable load even for small telescopes rather fancier than the Astroscan. On an Astroscan, the weight of a camera will definitely give the rubber roller focus mechanism something to think about, not to mention make the ball aiming system exceedingly cumbersome.

Don't expect to be able to find an Astroscan in your local telescope shop if you're not in the States; Edmund apparently don't currently distribute their products to other resellers. You may well be able to find something like the abovementioned Bushnell clone or Orion StarBlast, though.

Edmund Scientificcatalog

Unfortunately for me, this is one of those northern hemisphere astronomy books that's of limited utility to someone who lives in Australia. For the same reason, the nifty rotating Star And Planet Locator that also comes with the Astroscan isn't any good to me.

You can also use a simple empty-tube "prime focus" adapter with the Astroscan, but that won't give you as much magnification, and with many cameras will restrict the image to a small circle in the middle of the film (or digital sensor). You can use a "Barlow lens" between 'scope and camera to enlarge the image, but eyepiece projection is still likely to work better.

It's not a giant Thermos flask, or some kind of trench mortar, or (as has been noted in literature) a bomb. It's the Edmund Scientific Astroscan, and it's something of a timeless classic of the basic astronomy world. Despite the fact that it's been around for about 28 years (at time of writing), it remains an excellent all-round basic telescope.

There's also a rubber eyecup that you can wrestle onto an eyepiece if you like, but it's optional, and not very useful at all for ordinary night-time viewing.

30X magnification doesn't sound like much by the standards of the average discount-store telescope (of which more in a moment...), but it's actually quite adequate for a lot of stargazing. A lot of things in the sky are surprisingly big - they're just rather dim. You need light-gathering ability (and a dark, non-light-polluted sky) to see them, not zillion-times magnification.

Along with portability comes toughness. No telescope can be used to hammer in tent pegs (well, actually, many astronomers would opine that recent Tascos should be), but if you bump the thing on the door frame on the way out you shouldn't then have to spend an hour recalibrating it. The Astroscan passes this test; its glue-mounted mirrors are there to stay, unless you're extremely impolite to it.

The Astroscan's pretty darn portable even with its base. It only weighs about 5.8 kilograms (12.75 pounds) with the base; about 0.9 kilos (two pounds) less without it.

(If you're in Australia, try this search for eBay Astroscans. If you're in the UK, try this one.)

Look at the 28-year-old Astroscan today, and it really doesn't look antiquated at all. It looks as weird as it did on the day it was born, it works just as well, it costs less, and the total number of telescopes in its market niche is now... two.

A basic telescope should also not cost a fortune. You've got to accept that you're not going to get anything decent for fifty bucks, but if your telescope could cost, say, a fifth as much as a basic PC, that'd be good.

Lousy 'scopes with light leaks and poorly aligned, poorly coated glass may have a great big magnification figure on the side of the box, but will give you a fuzzy, washed-out view considerably inferior to that from a much lower magnification pair of binoculars costing the same amount of money.

A Dove prism is a type of reflective prism which is used to invert an image. Dove prisms are shaped from a truncated right-angle prism. The Dove prism is named for its inventor, Heinrich Wilhelm Dove. Although the shape of this prism is similar to the shape described by a Dovetail joint, the etymology of the two is unrelated. Refraction at the entrance and exit surfaces results in substantial image astigmatism when used in convergent light. Thus the Dove prism is used almost exclusively for images appearing at infinity.

The primary difference between eyepieces is their magnification. A telescope's overall magnification is equal to its objective (lens or mirror) focal length divided by the focal length of the eyepiece; the shorter the eyepiece focal length, the more magnification you get.

Newtonian reflectors can have a lot more aperture (and thus light-gathering ability) than refracting telescopes of similar length, and they're inherently "apochromatic" - they have no chromatic aberration, in which different colours in the image are focussed in different places. There may be a little chromatic aberration from the eyepiece lenses, but that's it.

Because of the standard thread, it's possible to attach the Astroscan directly to a tripod head, but its considerable offset weight will be too much for most tripods to hold up at angles far off vertical. Screwing the Astroscan's base onto the tripod and sitting the telescope in it lets the tripod head stay vertical, while you swivel the 'scope in its base as if it were sitting on a table.

Plossls are a good eyepiece price/performance compromise; they give a decent apparent field of view (how big the image appears to be when you look into the eyepiece), but don't add terrifying amounts to the cost of your 'scope package. It's quite easy to spend much more on one fancy ultra-wide eyepiece than the whole Astroscan package costs.

The basic Astroscan package costs $US199 today, which is rather less than it used to cost. Back in 1979 (when it was still called the "Astroscan 2001"; the then-futuristic number on the end of its name was quietly deleted a while ago), it retailed for $US169.95. That's an easy $US450 in 2004 dollars.

Read basic telescope guides and, frequently, the first thing mentioned will be that if it's in a department store, it's rubbish. Nowhere that sells socks also sells good telescopes.

The quick-release plate for my Manfrotto tripod didn't fit properly between the legs of the Astroscan base, but that's nothing that a longer screw and a few washers won't solve. You might not be able to get the base onto a really cheap tripods with no detachable mounting plate at all, but tripods that do have a plate (and for which you can buy extra plates, one for everything you want to put on the 'pod) start at quite reasonable prices.

Edmund ScientificAstroscan manual

Peering down the barrel of the Astroscan lets you see both of these mirrors. Once you get past its bubble-bottomed casing, the Astroscan's a classic Newtonian.

In the light of day, you can get much higher magnification out of all kinds of telescopes, including the Astroscan, but the aiming problem remains, and high magnification is often surprisingly pointless if you're looking a reasonable distance. Disturbances in the air (it doesn't need to be very hot for heat haze to appear over a few kilometres...) impose a limit on the resolution you can achieve in the daytime, unless you're looking up at the sky - where there's not a whole lot to see in the daytime.

This basic Astroscan package comes with two Plossl eyepieces (or Plössl eyepieces, if you want to be all umlauty and correctly reflect the name of the Viennese inventor of the things, back in 1860); a 28mm wide angle, and a 15mm for getting closer. The Astroscan's objective focal length is 445mm, so the 28mm objective gives about 16X magnification, and the 15mm gives about 30X.

Maybe it'll lead to something more, maybe it won't, but you really won't find a better introduction to the hobby anywhere, and even if you move on to a severe case of astrophilia, your Astroscan will probably still get used.

The Astroscan ball-mount idea isn't exclusive to cheap 'scopes, by the way. Portaballs use it, and their prices start from $US2400.

The globular base of the Astroscan fits into this simple cast aluminium stand. Three felt pads between plastic and metal let you swivel the 'scope to any angle. You can also leave the base behind and sit the 'scope in your lap, or hang it from a strap (of which more in a moment).

A basic telescope should also be easy to set up. Point and shoot, not unpack and assemble and level and calibrate and wind and fiddle and point and repoint and tweak and curse. Another win for the Astroscan. Newtonian 'scopes are usually fussy beasts, requiring frequent re-alignment of the mirrors and very careful handling. The Astroscan Contains No User-Serviceable Parts, and Just Works.

There's something to be said for good old SLR film cameras when doing astrophotography, mainly because they allow very long exposure times with no noise problems. A few digital cameras these days - including my Canon EOS-D60 - are capable of exposures of many minutes without delivering noise-storm results, but film can be exposed all night with no problem.

The down side is that very fine control of aiming is pretty much impossible. But you're not meant to be using this telescope at very high magnification, so felt-on-plastic works fine.

Edmund sent me the basic Astroscan package, which they sell for $US199. There are plenty of Astroscan-compatible accessories available from Edmund and others, but there's nothing vital left out of the basic package.

(If you're in Australia, try this search for eBay Astroscans. If you're in the UK, try this one.)

The other reason why a film camera might be a better choice, apart from the fact that it doesn't cost much to buy the sort of old all-manual cable-release film SLR that's all you need for astrophotography, is that film cameras generally weigh less than long-exposure-capable digital SLRs.

In a lot of parts of the world, definitely including Australia where I live, a drive of an hour or two will get you far enough away from badly designed streetlights (like those "orb" lights that fling photons everywhere except down around the light itself...), giant searchlight-tipped casinos and idiotic upward-facing decorative pavement lights that you'll be able to see cool stuff, even through a cheap-ish telescope that a kid can carry.

The thread the Astroscan's base locking screw uses is the same as the one used on ordinary camera tripods, so if you remove the locking screw completely from the base, you can attach the base to any normal tripod. This is handy if there's no table-like object where you want to do your stargazing; if you just sit the Astroscan's base on the ground you'll have to curl up to peer into the eyepiece.

The rubber eyecup, by the way, came in a little bag stapled to this warning card. This side of the card makes clear that when the piece of rubber kills you, it's not Edmund's fault.

If you don't live in the USA, things are a bit more complex. Edmund don't currently ship outside the USA, but their sibling site Ward's Natural Science does, and will even do so for a tolerable price after a certain amount of back-and-forth, according to one of my readers.

If you don't live in the USA, though, you're out of luck there. Edmund, for some reason, don't currently ship outside the USA, and apparently don't distribute their products to any other resellers either. Most Amazon dealers of things other than books and movies also don't ship outside the USA.

There's still value to the material in the Sky Guide about how stars appear to move, how to find them, and the behaviour of telescopes, though.

The M42 nebula, in contrast, is some 66 by 60 arc minutes - it'd take a two-by-two block of moons to cover it. But it's not very visible to the naked eye, because it's not very bright.

Just try not to accidentally head-butt the telescope the first time you squeeze your, apparently, freakishly large head through the strap.

The Astroscan's main mirror has a diameter of 4.25 inches, but when you take into account the light loss from the angle-mirror obstruction, its effective diameter is 4 and an eighth inches - 105mm. This is a pretty big aperture for a 'scope a kid can carry.

As for everything else, though... well, you'll be able to see a tantalising graininess when you look at the light-polluted sky, showing you how many stars and other interesting things are trying to make themselves known to you, but you're going to have to get the hell out of Dodge if you want to see what they actually are.