Ozzzy's Cosmic Time Machine part two
The CGE loaded for bear as I use it now
If you read about my C8/HEQ5 you'll know I spent a lot of time and effort in
turning a vanilla HEQ5 into an imaging mount. Well, when the Canadian dollar soared above the US dollar in
2007 I decided it was time to get something with a bit more 'smarts' and capacity. I opted on a Celestron CGE
after much mulling over the Losmandy G11, the CGE and the Vixen Sphinx SXD. My requirements were much the same
as those that drove me to the HEQ5 with transportability being paramount. As the mount would be purely for imaging
I also purchased an SBIG ST4 autoguider with it.
The telescopes
The mount will usually hold two of my three elescopes. Any can be used for imaging or guiding depending on the field of view that I need.
The first scope is a Stellarvue Nighthawk II (sadly being discontinued). This is an 80mm f/6 refractor that has a
prodigious field of view and little enough abberation that it delivers great images. It's just an achromat, but
Stellarvue designed the optics well and it's mechanics match the optics.
The second scope is a Stellarvue SV102ED refractor. This 102mm f/6.95 scope has optics that are even better than the
NH2's using a Schott extra-low dispersion glass element'. As with the NH2 the mechanics are
as good as the optics and the Feather Touch focuser is a dream.
The third is a mid-90's Celestron C8 with VERY good optics. Usually it is operating at f/6.3 but I can go to f/10
for small objects or 'the sky is the limit' for planets using a barlow or eyepiece projection.
The mount
The CGE is a classic German equatorial. Without waxing too poetic it's very good. My reason for buying this instead
of the G11 were:
- Collapsing tripod legs
The CGE has a heavy folding tripod. This makes setup and tear-down a lot simpler than the Losmandy
tripod which has to be put-together and taken apart to transport.
- A user-friendly hand controller/computer
The Gemini system, while very accurate, has a user interface from Star Trek TOS. Listening to a new
Gemini owner curse the system for 2 nights running at the dark site gave me pause to think about the G11. The
NexStar controller on the CGE is basically a no-brainer to operate.
- Top notch gears and motors
The CGE employs accurately ground steel worms and bronze Berg gears along with very good Pittman LO-COG servo-motors with built-in encoders. The
gears and motors are housed in heavy 'motor boxes' and are protected from the elements and from being
bashed around in transport.
- GPS time and location
The CGE uses my Celestron CN-16 GPS peripheral mounted with a home made bracket to configure time and location information.
Some modifications and projects
No mount is perfect and the CGE is no exception. But for $3000USD it holds it's own with any other mount in the
same price range and payload capacity. Unfortunately, there are some places where Celestron cut corners and
I seem to have found them. Here is a list of things I've built to fix the problems or just to work with the CGE.
- Side by side mounting fixture (not a CGE specific fix)
In an effort to control flexure and aid balance this fixture was constructed.
- Power, anti-dew, focus and shutter in one box
- Hand control cable extender
The CGE hand controller cable is short. I bought a 6-wire telephone extension cable and a female-to-female coupler from The Source (ex Radio Shack) that allows
me to have the hand controller 5 meters from the telescope. More cabling but at times handy.
- Leg clamp knobs
The T knobs on the legs are cheap and ill thought out. Here's a fix.
- Azimuth lock-down knobs
These are even cheaper and one broke the 2nd time I had the mount out. Go you your favourite specialty
fastener vendor and buy new ones. While you're there, buy a set of 6 knobs to replace the hex-head screws
that hold the mount to the electronics pier and the pier to the tripod. They're the same thread.
- RA and Dec cables
These are standard Cat5e STP network patch cables. They're NOT made for what Celestron is doing with them
and the design of the mount lacks foresight. Throw them away! I don't feel that the ScopeStuff cables are any better as you'll have
much the same problem which is the cheap foil sheilding and use of a drain wire. Buy Hi-Flex cables from L-Com.
They're very expensive but worth every penny. I've not had a 'No Response' or runaway slew since I bought them.
- Azimuth adjuster
- Auto-guider shelf
I needed a 'shelf' for my ST-4 auto-guider as the unit took up a lot of room on my Starizona accessory tray. Here is what I came up with.
Now, does the CGE work? You decide.
This image was my first with the setup. Shot through the SV 80/9D, UNGUIDED with NO PEC training. 50 minutes of exposure 5 minute subs
using a Canon 350D (unmodified).
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