This is the second in a series of reviews for my new CGEM mount from Orion Telescopes and Binoculars. This review covers the first night out with the CGEM. It was mostly a test of the goto functionality of the telescope.
I recived the CGEM on Monday September 14th, 2009 but didn’t get a chance to put it to the real test until the following Thursday. As mentioned in my first review of the CGEM, it was cloudy the night of receiving it. My chance came a few nights later with partly cloudy skies.
Setting up the CGEM
I’m not keeping the CGEM in the observatory for now. It is fully set up in my garage. To transfer it to my yard, I remove the optical tube and counterweights and set them aside. This leaves the mount on the tripod. To make it easy to get through the door and fence gate in the backyard, I shorten the legs of the tripod. I can get a firm grip on the top of the tripod legs and carry it to the backyard. I avoid grabbing the mount as to not strip out the gears. Although the mount/tripod combination is a bit heavy for me, it seems to be fairly well-balanced for carrying (without straining the back too much!).
Setting it back up in the yard was a fairly quick process. I set the tripod down and adjusted it to be roughly aimed at Polaris. I didn’t need a precise polar alignment since I was only testing the goto capability of the CGEM. Then I re-attached the counterweights and optical tube.
After powering up the CGEM, I started the Two-Star Alignment process. First, the index marks on the RA and DEC axis were aligned. Then, the hand controller prompted me to to select the first star.
Arcturus in the constellation Bootes was the first on the list of named stars and I noticed that it was still visible on the western horizon. This was a nice bright familiar star to start with. So I hit enter and the telescope started slewing automatically in the direction of Arcturus. Then, the hand controller prompted me to center the star in the viewfinder. After doing this, I was instructed to center it in the eyepiece then press the align button.
Then, the CGEM prompted me to add a calibration star. I must have gotten too anxious to try out the goto and I by-passed this step. Not good! The goto was not accurate at all.
I decided to start the alignment process over completely and I added the star Altair for calibration. This is where it got exciting! The first object I selected in the hand controller (to slew to) was Jupiter. To my amazement, it centered the planet almost perfectly! And I must say, Jupiter and it’s moons were an awesome site in the eyepiece!
After my first stop at Jupiter, it was time to try a Messier object. I saw that the constellation Hercules was up so I commanded the CGEM to slew to M13 (The Hercules Star Cluster). Again, the goto was spot on! I was amazed at this point how easy it was to set up the goto on the CGEM and how accurate it was. One recommendation is to have a star chart handy at the telescope. The CGEM hand controller provides a list of stars to choose from at each stage. If you have a laptop at your observing site, then there is a free program called Stellarium that is nice to use. Learn about Stellarium here on AstroPhotography Tonight.
I continued with my goto test by hopping over to the Ring Nebula then the Dumbell Nebula. Same result on the accuracy. After the second alignment, all objects were almost perfectly centered in the eyepiece. The goto test was a success! At this point, I was thoroughly thrilled with the CGEM.