Mouseover of the small thumbnails to the left to show larger images of the mount.

The Celestron CGE mount was, and still is, a popular mount amongst astrophotographers. The CGE-Uncensored CGE yahoo user group is still alive and very active. The mount has some scratches (see images) but still performs as when I got it (a little better actually). The CGE performance is generally considered to be slightly better than e.g. Losmandy G11. One should note that the CGE's performance varies quite a lot. As an example uncorrected periodic error has been found to be as low as plus minus 2-3 arcsec and as high as plus minus 60 arcsec. The "normal" periodic error is somewhere around plus minus 15 arcsec. Using periodic error correction (PEC) this can be brought down to about half that value. Since the period is roughly 8 min, a smooth periodic error of plus minus 20 arcsec is easy to guide away. Thus guiding is necessary with this mount for astrophotography (longer than say 30seconds depending on image scale and atmospheric conditions). The periodic error of this particular CGE mount is roughly plus minus 10 arcsec as can be seen from the left graph below (obtained from PemPro2).

After periodic error correction this was brought down to plus minus 5 arcsec as can be seen in the graph to the right. The high frequency variations that still remain can still be handled by guiding (provided the guide period is not too long - see image at the bottom of this page) and is probably due to a worm gear bearing, which can be replaced.

A more detailed description and data for this particular CGE can be found here together with a description of the CGE motors here.

Since this was/is a very popular mount there are a lot of different descriptions out there on how to improve the mount performance by changing parts and modifying the mount. The most common one is to change gears in the RA and DEC motors, which is outlined in this pdf put together by Mike Dodd. Exactly this modification has been done to the mount on sale here. There are also a number of sites that offer CGE tuning (re-greasing etc),e.g. deepspaceproducts and astrotroniks.

One can also improve the periodic error by attaching a "Telescope drive master" described here. Which is sold e.g. here.

The carrying capacity is claimed to be a bit more than 30kg (65lbs). Here is a link to the manual in pdf format (where you can find e.g. set-up routines as well as data on the mount) as well as a link to celestrons CGE page.

The mount can still be found from dealers and then sells for USD3800-4000 (e.g. see here). This mount in used condition usually goes for USD 2000 (e.g. see here) to that shipping and tax is added. In Swedish kronor this will be 13 000 SEK. I will sell for 10 000SEK.

The mount comes with hand control, power cable, one counter weight, cable for PC control, NexRemote software with serial #, 1.25" diagonal, Sturdy field tripod, manual and the following non-standard acessories:

• Polar alignment scope (see image). This is fastened to the mount for fast rough polar alignment.

• PC programming cable (see image). Used for firmware updates. I believe the mount has the latest firmware, but in case there is a newer one (on e.g. the yahoo group) this cable is needed to update the mount.

• PC control cable (see image). Used to connect the mount to a PC (not the same as the programming cable). It attaches to the bottom of the hand control.

• Hand Control Holder (see image). Attaches to one of he tripod legs.

Below is a 5min subexposure of the Bubble nebula taken thru a Celestron C8 at f10 using a Baader modified Canon 40D. The image scale is 0.58 arcsec/pixel (focal length 2032mm and pixel size 5.7micrometers). Click on the image to view a full sized image.