LX200 Telescope

August 11, 2013

Astronomy, Technology

Meade 10 inch f/10 LX200 ACFMeade 10″ f/10 LX200 ACF

I’ll start with that “ACF” part because that tells you what kind of a telescope I’ve purchased. It looks an awful lot like a Schmidt Cassegrain because the light path is “folded up” into a similar package to a Schmidt. The 10″ f/10 suggests a 100 inch light path but the scope is shaped less like artillery and more like a pony keg, like a Schmidt. But make no mistake, it’s not a Schmidt.

John Dobson use to say “Newtonian Schmootonian.” “Cassegrain Schmassigrain.” “Schmidt Schmidt.”

That was the famous astronomer’s way of criticizing the softer stars and reduced contrast a Schmidt offers in exchange for increased stability and portability. He meant that a Schmidt was its own worst critic, or something to that effect. John didn’t always stop to explain himself. I was walking with him once and talking philosophy when he saw a dandelion growing next to the path. Without slowing down he stooped and grabbed and plucked a handful of the weed. He stuffed it in his mouth and munched it like any normal mid-morning snack as we continued along the path.

When Meade first introduced the ACF design it was marketed as a Ritchey–Chrétien scope, just like the Hubble Space Telescope as well as many large professional observatory scopes. Apparently the first models Meade shipped even have a prominent “RC” printed right on them. But then there was an uproar over the rights to the name and a debate over minor engineering details or something, and legal remedies were applied. Eventually a court driven injunction was enforced. The end result is that Meade switched over to the ACF moniker instead of RC. It stands for “Advanced-Coma-Free.” So by using the AFC name, and the Ritchey–Chrétien optical solution, Meade offers consumers the desirable aspects of a Schmidt, without the drawbacks. I was totally skeptical until I saw the proof for myself.

Stars are supposed to look tiny, round, and plentiful. And without rainbows.

Comparison showing the optical advantage of ACF over Schmidt-Cassegrain.
Sharper stars and more of them.

A lucky shot

Actual image through my 10″ LX200 ACF – photo by Brad Snowder
Hey John, Coma-Free, Schmawesomee (alright don’t judge me)

Refractorman's life is always intense.Like a lot of observers, I cut my teeth on Newtonians. Even though a refractor is in a sense the purest thing, with all those beautiful diffraction rings, and pitch black sky, and pinpointy stars and crispy sharp planets. But good refractors are damn expensive inch for inch, and the “per inch” part is what the resolution and light gathering of any telescope is all about. A good refractor can easily cost you 1000 of your favorite dollars per inch of aperture. Whereas good Newtonian can often be as cheap as 100 dollars per inch, or even less these days actually. To be honest, a brand new ACF is as expensive as most refractors, but a 10 inch refractor is an incredibly large, long, very heavy, and rather cumbersome instrument. It is a chore. It is a job. It is a career choice. An ACF is a more naturally stable photography platform, and it fits inside of a vehicle instead of on top.

The Meade LX200 ACF is a pretty thing, with lots of built-in smarts.

The on-board “go-to” computer and control paddle has lots of bells and whistles. When you first turn it on, the scope swings itself around and back and forth to determine its sense of levelness, while making classic “bzzzzt” robot noise. Then it “listens” for GPS satellite signals so it can calculate its longitude and latitude, and the precise local time. Once it is satisfied regarding time and space, it aims at one of the brighter stars currently in the sky. The read-out asks for confirmation of success. Even if it isn’t perfect, it’s close enough that you then use the paddle controller to center the star in the eyepiece and it measures the correction. It does this for a couple more stars and that’s it, you are polar aligned. If you decide you need to be even more precise, like for extra-long exposure photography, you can refine it. You can also “train” the computer to compensate for any periodic errors in the tracking. It’s a pretty freaking smart telescope.
Does the steering wheel move the cursor?The computer will recommend stuff to look at with its “what’s up tonight” function. The list includes man-made satellites and spacecraft like the International Space Station, which it will find and will even track for you, if you ask nicely.

The tripods that come with the LX series are super heavy duty, unlike the flimsy tripods that use to come with the Schmidt scopes of yesteryear. These guys are like the Lunar Land of the Apollo missions.

The LX200 comes with a pretty good 26mm wide angle (60deg) eyepiece. It has a flat field right to the edge, with good contrast etc. It’s tasty but not Nagler tasty.
Save room for the barlow.
Sometime in a previous millennium I acquired a nice little black and white Meade 4″ f/10, which seems to make an ideal guide scope for my LX200. I also had an Astrophysics 8×50 finder scope that I like better than the stock Meade finder, mostly because of the reputation behind the name. Astrophysics has a rep for making high quality refractors and the finder is a little refractor so what the hell.
I mostly like to set it up next to my desk and bask in the glory.
At the time I bought my LX200 they were throwing in a free DSI-II astro-camera. I set it up with the 4″ and a laptop computer to use as an autoguider. I just recently realized that it is probably a good camera to use with my solar scope because of its sensitivity to the IR range, so I’m probably going to be working on getting that going soon.

If you get a bad wedge, you're going to have a bad time.The LX200 tracks just fine with the fork mount simply attached to the tripod, as an alt-az mount, without an equatorial wedge. But long exposures will result in “field rotation” with an alt-az arrangement. The wedge allows you to align the axis of rotation of the scope with the axis of rotation of the Earth. It’s like the difference between turning your head and turning your whole body. If you just keep turning your head and not your body, things eventually get twisted. That’s not a perfect analogy, actually that’s messed up. Scratch that. But I knew from experience that I needed a wedge and a cheap wedge is just asking for frustration. So I spent the extra coin and got a high-end model. The “Evolution” wedge is a hand machined high-precision fine-tuned athlete of a wedge. The adjustments are as smooth as silk. It is a dream to use, which is the opposite of some cheaper wedges. But this guy runs about $700.

Proper geekdom requires loading up your LX200 with accessories so I added a Losmandy counterweight system. Again, I figured since everything else was first class, why not Losmandy, a company which has earned a lot of respect for their telescope counter weight system.

Warning, do not shower with telescope (except meteor shower).The Astrozap dew shield makes the tube assembly look doubly geekalicious. We have a lot of dew to shield here in the Pacific Northwet.

Other accessories I’ve added include a 2″ TeleVue Everbrite eyepiece diagonal (reputation again), a red dot finder, tripod case, remote power station, and a heavy duty, water-proof, UV proof, sad astronomer caught in a dust storm proof, canvas scope cover. It’s designed to protect an LX200, the accessories, and tripod, from the lens cap all the way down to the ground.

JMI is a company that makes astronomical accessories including a great hardshell transport case with handles and wheels for the LX200. The stock wheels are the small hard plastic ones like airport luggage, so I got the optional big pneumatic tires, for trips across rural fields. I’ve since decided the big wheels aren’t terribly necessary. I rarely set up far from my Jeep.
Chrome mag wheels would be nice.
The accessory I’m currently working on getting constructed is a backyard dome, so I can keep it all set up and ready to go on a moment’s notice. After much program planning and many strategy sessions, I’ve finally managed to convince my wife that a personal observatory is absolutely essential (thank you powerpoint), so the rest of the project should go quickly.
Tell your neighbors it's a missile silo - second amendment and all.Carpe Noctem.

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