James's Telescopes

Telescopes

 
 

I don't really collect telescopes, but if I see something I like for a good price I'll buy it. This is my current inventory, listed in order of aquisition. (Photos will be added as I can get them.)

Orion logoOrion 8-inch Dobsonian

Orion 8-inch Dobsonian telescope

This started out as a father's day gift for The Old Man from The Family. I didn't know anything about telescopes, but I was the one who did the research, and I ended up buying into the notion that you get a lot of telescope for your money with a Dobs. It's true — though in retrospect I don't think it's a good beginner's scope.

Dobsonian refers to the mount; in this case, it's a alt-azimuth floor (or ground) mount. Because the barrel of the scope is so large, you just push or "nudge" it into position. Dobs mounts are inexpensive and can easily support a big scope, so they're very common for mirrors 6-inches and larger.

This particular one is an 8-inch, ƒ/64 model: the mirror is 8-inches in diameter and the focal length is 64-inches, hence ƒ/8 (if the focal length were 80 inches, it would be an ƒ/10).

There's nothing wrong with the scope per se, except that we had the common beginner problems — we didn't really know what we were doing (reading books and articles only gets you so far) and we didn't know anyone who did. The moon came in fine but nothing else looked like anything. It now sits in storage.

 

Celestron logoCelestron Autostar 114 GT telescopeCelestron Autostar 114 GT

Bought from Goodwill's online auction site; the price was reasonable because I could pick it up in person instead of paying for shipping.

This is a GoTo scope, which means it has motors in the mount and a computer in the hand-controller.If you set it up in a standard configuration (level and pointing north), and then help it locate the position of a couple of stars, it'll know where everything else is and can Go To an object on its own.

Years after the debacle with the Dobs, I'd occasionally think about trying another scope, something that would be better for a beginner. Finally, after nearly two decades, the price of GoTo scopes have come down and I thought it might be worthwhile as a beginner's aid. I know some people say they aren't good for beginners because you don't learn the sky that way; but considering the learning curve you're up against with scopes, I'll take the crutch and use it. If it works and I like it, I'll end up learning the sky anyway.

Like the Dobs, this is a Newtonian style scope; it has a mirror on the back (114mm in diameter) and a little diagonal meter near the front of the tube, and the eyepiece mounts on the side.

The weather here has been terrible for sky watching, so I haven't been able to do much with it yet other than to make some quick comparisons with the Meade below.

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Meade DSX-90 telescopeMeade logoMeade DSX-90

I bought this at a thrift shop for $40. It was missing the Autostar hand controller and the accessory viewfinder.

Like the Celestron Autostar, it's a computerized "GoTo" scope, which means that if you set it up in a standard configuration (level and pointing north), and then help it locate the position of a couple of stars, it'll know where everything else is and can Go To an object on its own.

This one is a Maksutov-Cassegrain. Without getting technical, the main thing is that instead of having the little mirror near the front of the tube set at an angle and the eyepiece mounted on the side of the tube, the mirror is straight and bounces the light back down through a hole in the center of the mirror, so the eyepiece is on the back end (bottom) of the tube. I think it's a nice setup for photography, as the camera is in the back of the telescope rather than hanging off the side. For small digitals it may not matter much, but for my heavy Canon 40D, I think it matters a great deal.

According to an article on the website Cloudy Nights, the optical tube for this telescope is the same as a Meade ETX-90, painted silver instead of blue; and it's mounted on a Meade DS GoTo motor mount, rather than an ETX motor mount. The DS mount is a step down from the ETX, but I don't have enough info regarding why.

Other than the motor mount, for our purposes this is compatible with the ETX-90 and all accessories that fit it would fit this one.

Meade said that any of their Autostar hand controllers would work with this machine. I know there are at least four models, maybe more. The ones of which I'm aware are, in order of introduction, the 492, 493, 494, 495, 497, and the Audiostar. A brand new Audiostar is fetching $150 (January 2017); used Autostar 497s are starting at about half that, if you're lucky, up to $150 themselves. 494s and 495s are a bit less but harder to find. I never bothered to look at the others.

I ended up buying a 497 from George Cushing, who has the Telescope Scrap Yard. You can find him on the Cloudy Nights website.

The article about the DSX that I mentioned above is certainly right about the tripod: it's a pair of legs that seems more fitting for light-weight digital cameras than a telescope. The advantage is that it's easily luggable, but the disadvantage is that it's about as sturdy as if it had been made with tinkertoys.

I haven't decided what to do about this yet. I've got a big, heavy tripod that might become its new home if I can get the scope head to fit on it. We'll see. Another thing to do would be to hang a heavy weight as ballast on it, but the problem is where and how to hook it up. The cross-piece in the center is more of a detriment than a help; it's flimsy and it's right in the way. If I don't want to re-design the tripod (and I don't), then the thing to do is make up some kind of three-point harness, kind of like an upside down Y with three arms: each upward arm tied around the top of each tripod leg; they connect together below the tripod's center section, and then the ballast is hooked to the bottom arm of the Y. Make sense? If I make the thing, I'll put a photo here.

It's been raining here so I haven't had a chance to really try it yet, other than to determine that the Autostar and the motors work.


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