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Celestron 21024 FirstScope Telescope...any good?

shawmutt

Squirrel Murderer
shawmutt
Joined
Jan 17, 2009
Messages
2,037
I don't have any experience with telescopes, and I was wondering if this one was any good. Amazon is giving me $15 off, so it's only $30. It will be mostly used with my kids as they get older.
 
A little 3" reflector like that is not a bad choice for moon watching and seeing that Saturn has rings, or that the moons of Jupiter move. And you can look at nature with it, too. Birds, squirrels, etc.

I can't see how you can go wrong with it.
 
shawmutt said:
I don't have any experience with telescopes, and I was wondering if this one was any good. Amazon is giving me $15 off, so it's only $30. It will be mostly used with my kids as they get older.
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For a beginner's telescope, a 3" reflector isn't bad. On the upside, the 3" aperture offers a significant amount of light gathering power and resolution, and inch-for-inch it's vastly cheaper than a similarly sized refractor (which can easily cost 5 to 10 times more for the same aperture). On the downside, reflectors are in general tougher to use than refractors. The optics need to stay aligned, and can get knocked askew with even a moderate jolt (which seriously affects optical performance, often making objects appear lopsided and unsharp). And the open tube design can make it hard to keep the optics clean. Plus, not everybody "gets" how to observe with a reflector -- the idea of looking down through an eyepiece with the telescope pointed off at a 90 degree angle towards the sky may not seem natural to everyone. All these drawbacks can be overcome, but in general it does take a bit more motivation on the part of the observer.

One of the first telescopes I owned as a kid was a 3" reflector, which probably wasn't nearly as well made as this Celestron model. Pretty much right off the bat I could see things with it, including craters on the moon and Jupiter (which showed up as a bright, slightly flattened disk with its four Galilean satellites). With a little more practice I could see the rings of Saturn, the Andromeda galaxy, and other objects. Although the telescope wasn't particularly portable, I dragged it all over creation with me. It worked well enough to help cement my lifelong interest in astronomy.

This telescope should be pretty much superior to my old model in every way. The mount looks sturdy (mine was rickety as hell) and the eyepiece holder looks like it accepts standard 1.25" eyepieces, which means you can upgrade the telescope's performance by buying more eyepieces. (My telescope had cheap plastic eyepieces; I was constantly experimenting with other eyepieces by jamming them into the holder as best I could.) And the Dobsonian design should make the scope easy to point. From the looks of it, the scope appears to be relatively "fast" and short focus. This means you probably won't be able to get more than maybe 75x to 100x usable magnification out of it, which is somewhat less than you could for longer focus instruments. Conversely, objects will tend to be brighter an easier to find, both major plusses for beginners.

On the whole, I'd say this is a good scope for the price. And Celestron has a fairly good reputation in the industry, so it should be reliably well made. I'd say this will make a good beginner's scope -- I certainly wish I'd had one when I was first starting out.
 
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Celestron is a reputable company.

IMO, you should spend a thou on a Dob. The "Oh wow" reactions are worth every penny and then some.
 
Have you looked at the "Galileoscope" kit?
"The Galileoscope™ is a high-quality, low-cost telescope kit developed for the International Year of Astronomy 2009 by a team of leading astronomers, optical engineers, and science educators. No matter where you live, with this easy-to-assemble, 50-mm (2-inch) diameter, 25- to 50-power achromatic refractor, you can see the celestial wonders that Galileo Galilei first glimpsed 400 years ago and that still delight stargazers today. These include lunar craters and mountains, four moons circling Jupiter, the phases of Venus, Saturn's rings, and countless stars invisible to the unaided eye. As of August 10, 2009, the kit is priced at U.S. $20 each plus shipping"​

The Celestron is probably a better scope, but the "kit" aspect might help get the kids more interested.
 
Pantaz said:
The Celestron is probably a better scope, but the "kit" aspect might help get the kids more interested.
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I dont think the kit scope has a lot going for it as a scientific instrument, however to have the oppotunity to view the universe using the EXACT same equipment Galileo did.........Just wow
 
Actually, the kit scope is a lot better than the telescope he used. The way lenses were made then was not very "scientific." They dealt with the extremely bad figure at the edges by just masking over the edges, leaving the center part that was not so bad to use for imaging.
 
BenBurch said:
They dealt with the extremely bad figure at the edges by just masking over the edges, leaving the center part that was not so bad to use for imaging.
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Alot of really cheapo refractors these days do the same thing. Ditto with some inexpensive binoculars.

And avoid "ruby coated lenses" like the plague.
 
Basically it is a red filter to cut UV glare in daylight applications. It substantially rejects light, and changes color perception. This might be helpful on a bright day at the horse track. It is the opposite of what you want in twilight, moonlight, or to view the heavens.

In any case you can apply filters to good binoculars should you want them.
 
DogB said:
Why? A quick Google showed that it's an extremely common marketing claim but without much explanation.

Just curious.
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I'm sure Wrangler can answer this in detail, but very briefly: Most lenses are subject to a phenomenon known as chromatic aberration. Basically, this means that the lens acts like a prism, breaking up the light it receives into colors. As a result, the lens has different focal lengths for different wavelengths of light. What this means for viewing is that when you focus an object (especially a bright one), you'll see the object surrounded by whatever color is out of focus. For instance, a bright planet such as Jupiter might have a purple halo around it -- and if you adjust the focus to get rid of the purple halo, a red halo may appear instead.

Modern optical systems can reduce chromatic aberration to varying degrees. For instance, achromatic lenses consist of two or more elements made from different types of glass, such as flint and crown. These different types of glass have different refractive indices which can be designed to more or less cancel out each other. The better the lens is made (which invariably means the more expensive it is), the less of a problem chromatic aberration is.

Some manufacturers of cheap optics attempt to reduce chromatic aberration by coating the lenses with so-called "ruby coating." This coating has nothing to do with the gemstone; it just happens to look red. This coating basically filters out the red light entering the lens. This means that you can focus on objects and not worry about the red component of its light creating a halo -- but not because it's been corrected; it simply is not there. It also means that objects you look at will likely appear with an unnaturally green shade.

I suppose this would be OK if manufacturers of ruby coated optics were very clear as to what you were buying and the tradeoffs it involved. However, they don't -- in fact, some of the claims I've seen appear to be outright lies. I've seen advertisements claiming that the ruby coating "pulls in" more light (it doesn't, in fact the opposite is true since red light is filtered out) and thus is comparable to "night vision" optics. So overall, ruby coatings are generally considered a sure sign of shoddy, low-quality optics. (Bear in mind that nearly all good quality optics use some type of coating on the lens, to reduce reflection and enhance light transmission. So coatings in general are a very sound, respected practice -- I'm just talking about ruby coatings.)
 
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Thanks Stellafane (and Ben).

I’m an amateur photographer and all my lenses are coated (to reduce internal reflection and cut down on flare) so I was curious as to why this was different. Now I understand.

:D
 
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