Celestron CGEM DX 1100 11" Schmidt-Cassegrain Telescope, 2800mm Focal Length

2014-02-22T19:00:00

After a couple years of practice, I got into guiding and the photography improved, and I also got a better planetary camera. I wanted to add to my other review (Deimos) but I don't have the login anymore. After this amount of time my only complaint is that the cord for the hand controller is very short and pulls on the scope when you use it. I think Celestron could have remedied this for $2. Also, the large aperture fogs up easily on the front plate so you will need anti -dew. Get a good car power supply from the auto zone to power the scope. The scope doesn't come with a battery so it can be disappointing when you first unbox if you don't have a battery. Anyway, here are some better photos taken with this scope, including a comet and the transit of venus.

Deimos

2012-05-06T21:00:00

When I first bought this scope I thought that maybe I had gone too far since it's so large and on the pricey side. The photo doesn't give a good indication as to how big this thing is, needs an average guy to stand next to it. It stands almost a foot taller than myself. Now that I've had it a while I have no buyer's remorse at all; this thing will allow me to grow in the hobby for 10 or 15 years to come. This scope is ideal for anyone interested in astrophotography because of the heavy German Equatorial mount, the balancing, low vibration and the precise optics. This type of mount takes a bit longer to set up than an alt-azimuth, but with practice and some hustle I can get all the pieces together and roughly polar aligned in about 8 minutes. More precise alignment for longer exposures can take another 5 to 15 minutes depending on how long your exposures are. I can usually do a 2 or 3 minute unguided exposure ok with 10 minutes of effort on polar alignment. For more precise alignment the software comes with an "All - Star" system that makes things alot quicker, and is good enough for most purposes. I would recommend using this rather than buying the polar alignment scope, which I got but is too difficult to setup properly and is quite inaccurate. For setup, it helps if you organize most things in a big wooden box or something so you're not running back to the car to get every little piece. Save the molded packing foam for your storage. The scope's software / hand controller works fine. The more info you give it in the form of alignment and calibration stars, the more precise the go-to becomes. If you're having difficulty locating a particularly dim object, just add a calibration star that happens to be near the object in question, and the scope becomes more accurate in that area. I've seen many things that I never saw before because of this goto. Occasionally I will still hit the maps to help center something dim. When properly aligned, the scope will keep an object in view indefinately for visual purposes. For photography, I can do from 2-4 minutes without guiding before streaking becomes a big issue (will get guiding equipment later) Out of the box, the optics appear to my novice eye to be well collimated. Eventually I will buy some Bob's Knobs' for when I need to adjust calibration but so far is unecessary. Compared to my old standard SCT-8, the edge HD seems to deliver more pinpoint stars, as advertised. I've never had "seagulling" or lopsided stars in my photos except from polar alignment errors. Right away I was able to take photos using a Canon Rebel camera with an T-adpater. They're not fantastic photos but for an inexperienced person using a standard camera and no guiding I think they're pretty good. My planetary photos are not much better than they were with a C8, because weather is more a factor than aperture for that, but the mount keeps the planets better centered and vibration free so the images / videos were much, much easier to take. I can visually see more moons around Saturn than I could with the C8. The scope comes with a giant 2" eyepiece and 2" prism. I don't really use these myself because they add quite a bit of weight to a scope that already is heavy in the back from the mirror locks and thick mirror. I'm normally using a camera, anyway. It doesn't come with a 1.25" diagonal but there is an adapter for the 2" and for the visual back, so you can use your old smaller eyepieces. The finder scope is large. I had to do some work on it to get it capable of aligning with the cope, invoking the application of some duct tape. The only criticism I would have the the azimuth screws are not very accurate. You're supposed to be able to slowly screw them one way or the other with precision, but in practice I have to just loosen them up, strong arm the scope to where I want it, then tighten them and hope the az doesn't shift in the process. The included images are what I took within the first 4 outings with the scope. I had never taken a deep - sky photo before that. The deep skies are with unmodified Rebel Canon, the planets are with an Orion webcam.

TRACI A.