New telescope decision

Hi John,

I recently got a CGE 1100 from AI and I have to say that it's a great scope. As Dave says, it's in three major pieces and I find that I spend about 10 to 15mins per night assembling it and doing a very rough polar-align in the garden with another 15 to 20mins doing the star alignment and calibration. Until you get used to this process, it can take much longer. This gives me decent pointing accuracy and is good enough for visual work.

I keep the electronics pier and the tripod as one piece and this is definitely luggable but not particularly portable. The OTA isn't heavy but depending on how you set up the tripod you may find yourself raising it to shoulder or head hight to secure it to the mount and this can be tricky.

One point to note is that the instruction manual is pretty poor so seek advice here or on some of the other boards - there's a good Google group for the CGE mount.

Good luck,

Chris

John (and others) --

There has been a whole bunch of info on the CGE mounts in the Mounts forum on CloudyNights over the last year or so. Evidently, earlier mounts (I can't remember the date, but perhaps those made before 2005?) had a host of issues, most of which have been worked out in more recent production runs.

Anyway, it's probably worth your while to check out some of the stuff there. A guy named Joe Cipriano basically completely rebuilt his, while others (including Jerry Wise, David Pavlich and Strgazr27) have had better luck with more recent ones. Try searching the Mounts forum on www.cloudynights.com for their names and "CGE".

Cheers,
-- Jeff.

I did some PE tests on my mount a couple of nights ago:

I used guidemaster to log errors (with no guiding). The mount had been drift aligned to a very high degree of accuracy previously. I imported the data into excel and graphed it. (I'll post the graph later)

Anway, I'm still trying to figure out exactly what I'm looking at but the PE graph seems to indicate a periodic curve of 7" peak to peak (Which would be amazing if true). However the curve drifts east in a linear fashion by about 8" per revolution of the worm. It may be partly due to differential refraction, I'm not sure yet.

More tests will be needed. Whatever happens I am so totally pleased with this mount. I left a guidestar sitting in screen with a crosshair on top of it. I went inside for about 20minutes or so. WHen I came out the star was still sitting perfectly on the cross hair. I couldn't beleive it.

Hi John,
Its great to see more club members coming onto the site, as for your currect mount, all you would need to do is reverse the polarity of the power going to the motor, note this is not reverse the polarity of the batteries or power supply you are using. All you'd need do is swap around the 2 wires directly feeding the RA motor and that will solve your southern hemisphere problem, although such a mount would probabily be difficult to get accurately working in an astrophotographic context.

As fot the CGE, I dont have one, the lads advise about sounds good to me. I currently own a 12 fork sct and will (all going well) be changing it to a high end german equatorial mount, something alot beefier then the CGE, from what I read the CGE is on a par with the meade forks in terms of hastle. Fellow CGE owners, please dont shot me. ...

Going from an 8" to an 11" is just about worth it, a 8" to a 10" isnt, maybe you should aim for the 14", thats what I would do. The image differance would be quite alot.

Dave (Grennan) --

If you mean that the curve drifts 8" over the worm period and then resets, then that's the worm component of the PE (as opposed to the worm-gear component).

If you mean that the curve has drifted 16" after two periods, then that sounds like your polar alignment is off slightly. You didn't say how long your drift alignment went with no movement. Was it at least as long as your worm cycle?

Atmospheric refraction doesn't seem right unless your target was under 20° or so.

Cheers,
-- Jeff

Thanks for the replies. I am much happier about parting with my deposit at this stage.

Dave (Lillis),

on switching the wires on the southern hemisphere drive, it is an AC synchronous motor operating at 220V. I had tried Meade (no joy) and one or two specialist shops who recommended a new mount for the OTA. This may be just for safety reasons with high voltages. I can of course always put a dovetail on the OTA and use it on the CGE. The tracking on the AC drive from what I remember was really good at the time.

John