CGE1100XLT review

I have now owned this telescope for just on a month and thought it time to do a short review of it having got to know it reasonably well in that time.

Celestron 11" f/10 Carbon fibre SCT OTA Specifications

- Optical Design: Schmidt-Cassegrain
- Aperture: 11"
- Limiting Visual Magnitude: 14.7
- Focal Ratio: f/10
- Focal Length: 2800mm
- Optical Tube Dimensions: 24" Long
- Secondary Obstruction: 3.75" (12%)
- Focuser Design: Primary Mirror Focusing System
- Weight - OTA: 27.5 lbs.
- Optical Coatings: StarBright XLT

I am very happy with the optical tube assembly build quality and optical performance. I leave nothing to chance & built my own Ronchi tester to test the optics for myself. The only problem I feel worth commenting on is the age old problem of mirror flop and image shift in a telescope of this design. I read before the purchase that Celestron has supposedly addressed this problem with the lastest batch of SCT's. They did not succeed. There is still plenty of image shift happening on my sample, take my word for it. If your aim is high resolution, long FL planetary imaging I suggest a moonlight focuser or something to that effect. Some sort of mirror locking device Like Meade offer would be nice too. It's good to see Celestron going with the wider & more sturdy dovetail bar on the 11". I think they should do that to the C9.25 as well. I never did trust the narrower bar on my ex 9.25.

CGE mount and tripod specifications

Drive Base Features:
- Autoguide port
- PC port
- Three accessory ports
- Real time clock. Maintains time even when powered down
- Strain relief power cord cable protection
- Backlit power switch

Drive Systems:
- U.S. manufactured Pittman 12V DC servo motors
- U.S. manufactured Berg bronze drive gear mated with stainless steel worm shafts
- Four point RA clutch system for no slip pointing precision

Tripod Features:
- Dual Leg Support.
- Center leg brace provides outward preload.
- Lower leg brace provides inward preload.
- Extendible powder-coated carbon steel legs.

SPECIFICATIONS:

Software:
- 40,000+ Object
- 400 User-defined objects
- Hibernate - maintains alignment even while powered down
- Polar alignment routines for Northern and Southern hemisphere
- Filter limits - displays only objects above the horizon
- Permanent programmable PEC - connects periodic tracking errors inherent in all worm drives
- Smooth ramping of slew motors to reduce wear on drive train.

Electronics
- Home sensors on RA and Dec axes
- Real time clock
- Fail safe slew limit switches in RA
- 12V DC Servo Motors with integrated optical encoders, 258CPR used in quadrature
- Encoder resolution .11 arcseconds.

Mechanics
- CNC machined aluminum and stainless steel components.

RA Axis
- 1" solid ground stainless steel shaft
- Two preloaded .9835ID x 2.047OD tapered roller bearing
- One 4.724 OD x 3.543 ID thrust bearing
- 180 tooth, 5.625" diameter enveloping bronze gear reloaded to maintain gear mesh while clutch tension varies, manufactured to AGMA 10 quality
- 4 point RA clutch system pre-loading a 4.65" stainless steel disk for no-slip drive and pointing precision.

Declination Axis
- 1" solid ground stainless steel shaft
- Two Preloaded .9835" ID x 2.047" OD tapered roller bearing
- One 3.250" OD x 2.500"ID thrust bearing
- 180 tooth, 5.625" diameter non-enveloping bronze gear preloaded to maintain gear mesh while clutch tension varies, manufactured to AGMA 10 quality
- 2 point Dec clutch system pre-loading a 4.65" stainless steel disk for no-slip drive and pointing precision
- Latitude Range: 10 to 60 degrees
- CGE Maximum Payload: 65 pounds

Tripod
- Tripod height: 36" to 50"
- Leg material: cold rolled carbon steel
- Upper leg diameter: 2.75" diameter
- Lower leg diameter: 2.375" diameter

I really like this mount. The pointing accuracy is pretty good, despite me only doing a 2 star align and no callibration stars added because I'm lazy & only image planets anyhow. The build quality is good but attention to detail is lacking. Typical massed produced item & you simply get what you pay for. You'll see what I mean after you have owned it for awhile.

PE peak to peak is +/- 10-12 on my particular mount. Now thats great for straight out of the box!

I have read where small problems can occur with this mount. like the limiting switches needing adjustment on occasion & all power & RA/DEC cables & connections must be up to scratch or you will have problems. Nothing like this has happened to me as yet. The only problem I have had is the hand controller refuses to keep the time. Every time I power up it gives me a completely different time...Edit: I think I have worked it out lol.

One can only track for a few minutes after hitting the meridian due to the mount head design, which can be a problem for some people. I think it's a blessing. Plan ahead for the meridian flip if you are doing long exposure AP.

For visual use the tripod is a nice height, but for photography purposes it could be a fraction shorter. Dampening times with the extendable legs fully retracted @ 700 magnification is a little under 3 seconds. Thats good enough for me. The mount chuckles to itself with the weight of the C11 perched on it.

The hand controller is relatively intuitive to use, however it does require some time spent with it to become fully functional with all the features. The polar scope for it is an optional accessory, which I think should have been added to the package. I won't be getting one anytime soon.

Overall I think this package as a whole is very nice for the bucks. I can certainly recommend it.

by John Earl