My Account

New to Astromart?

Register an account...

Need Help?

The Classic Orange-Tube Celestron C11 revisited

Posted by Robert Piekiel   04/28/2008 00:00:AM

The Classic Orange-Tube Celestron C11 revisited
The Classic Celestron Orange-tube C11 revisited:

If you wrestle with aperture versus portability, you might want to seriously look at the Classic Orange Celestron C11, a scope that may be the best combination of serious aperture with the portability of a much smaller scope. Even though it is about 25+ years old, consider this:

It is generally acknowledged that an 8-inch telescope has a significant light-grasp increase over a 6-inch, and that with an 8-inch, objects begin to look like what they really are, rather than just “faint smudges.” The light grasp increase of an 11-inch scope over an 8-inch is similarly impressive.

The problem is that when you move from an 8-inch to an 11-inch scope, the weight goes up considerably. This is compounded by the fact that many modern fork-mounted scopes of similar sizes are not meant to be disassembled into individual pieces (OTA and fork). This is to keep the alignment between the optical axis and the mechanical axes fixed to design specs for proper go-to operation.

If you take a go-to SCT that is fork mounted and try to de-mount the OTA from the forks, there is a chance that it will not go back together and keep the exact same alignment as when it was put together. This will NOT be a problem if you use the scope in an EQ mode (such as on a wedge), but it WILL cause a problem with accuracy of go-to pointing in the Alt-Az mode.

Fork mounts are great, in my opinion. They keep the eyepiece in a convenient viewing position and make the scope compact. No counterweight to mess with, no meridian flip, etc. I feel that fork mounts have gotten a bad rap due to somebody comparing them to tuning forks, and making claims that they vibrate excessively. Anyone in the acoustical engineering field will know that the way to completely “kill” the vibration of a tuning fork is simply to place a small object or weight on ONE of the forks. This will “wick off” the vibrational energy and completely kill the resonance. Most telescope forks are unbalanced due to tangent arms, etc., so they are inherently “dampened” from the start. The other thing to consider is that ANY scope needs to be on a suitable tripod that is designed to hold the weight.

Having said that, now look at some facts. My NexStar 11, which is a beautiful scope in its own right, weighs in at about 65 lbs., and is not something I enjoy hauling out for a “quick look.” Even though I have a Celestron C22 sitting in my backyard observatory, my observable sky due to trees and terrain is small, so I use mobile scopes quite often. I also do public astronomy programs at a local nature center and take my portable scopes there for work a few times each month.

My Meade 8-inch LX200 does not “come apart,” so it still weighs 37 lbs. That’s a large amount for just an 8-inch. The Meade 10 weighs 61 lbs., even heavier, and like the 8, is not meant to be taken apart. I’ve owned a Meade 12. The manual stated that it weighs 70 lbs., but for some reason I though mine tipped my scale at more like 90 lbs., and I was very worried I would hurt myself lifting it onto the tripod (and more so with a wedge). The Meade 14 is even heavier, at something like112 lbs. Out of the question for me unless I have a helper.

My Orange-tube C14 is a wonderful scope, and I can set it up and take it down in less than 5 minutes, but the pieces weigh in at as much as 68 lbs. Far better than a Meade 14, but lifting them into position takes a considerable amount of strength and control. (Once you have the heavy fork on the wedge you have to lift the OTA high over your head to slip it down in the saddles, all while holding it from essentially the rear cell!) As I get older, I’m not sure how long I’ll be able to handle it without help.

The solution to the problem is the Orange C11! It breaks down easily into pieces that weigh no more than 35 lbs. each, and it is a cinch to set up and take down. The OTA slips easily in and out of the fork, the fork hooks easily onto the wedge, being temporarily held by “keyway” bolts while you thread in the main bolts. It is easy to polar align without resorting to contortions to reach the bolts securing the Alt-Az movements while looking in the eyepiece. In other words, you can set it up and align it in just a few minutes with no more effort than putting up an 8-inch which does not come out of its fork. The 11-inches of aperture make a HUGE difference in performance, compared to an 8.

What’s more in favor of the C11 is that it uses the same tripod and wedge as the orange C14. These “legs” of the C14 provided excellent stability for itself, and so much more when used with the lighter C11. The locked-triangle tripod and heavy-duty wedge form a rock-solid, yet lightweight base for the C11. Once apart, the pieces fit into a car just as easily as those of an 8-inch.

Because of these items, the Orange C11 is ideal for just about anyone who wants a scope that is easy to haul out for a quick peek, or a lengthy observing session with decent aperture. The only thing you might want to consider is a drive corrector that will allow operation from a battery, rather than AC power, for portable use in the field. The fact that is a manual (not go-to) scope is something that you will have to consider. I HIGHLY recommend this scope for anyone with aperture fever who still wants the best in portability. As I said earlier, I prefer fork mounts to German EQs, and this is the biggest fork-mounted scope that disassembles into VERY easy-to-handle parts.

The Classic orange-tube C11 came along several years later in the Celestron line than the original 5, 8, and 14. Its optics were made from the former Vintage Blue-White C12 tooling. Because it came along later in years, there are not as many of them out there today (although they evolved it into a Black-Tube model with essentially the same specs) as compared to the classic 5, 8, or 14. Because there are simply less of them out there than the other famous Classic orange-tubes, you don’t see them up for sale very much on Astromart.

So, before you run out and buy yet another scope that will be used “part of the time” in your arsenal, consider an orange C11. It might be one that you hang onto for the longest time…

Bob Piekiel author of “Celestron The Early Years”