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Should I Move the Alignment Peg on My CG5?

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#1 palerider

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Posted 20 July 2009 - 05:38 PM

My CG5 was shipped with the Alignment Peg mounted between two of the tripod legs. There is another hole that sits directly over the third leg. Is it a good idea to move the peg over a tripod leg versus between two legs? I've been using it for about 6 months now and never had a problem. I stumbled across another thread where some people recommended moving the peg to avoid the possibility of the mount tipping over. How likely is that and is it really an issue?

Right now I'm only doing visual with a SV102ED, WO diagonal, Hyperion eyepieces, and a 9x50 finder. However, I do want to get into AP soon so I will be adding things like a guidescope, DSLR camera, etc. I'd rather be safe than sorry so moving the peg is not a problem. Thanks.

#2 Richard Turner

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Posted 20 July 2009 - 06:13 PM

My new CGEM was shipped with the alignment peg between two legs also. I don't know how likely it would be to tip over, but I've always liked to have the counterweight over a tripod leg. I would move it if there is any doubt.

Richard

#3 Blixx

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Posted 20 July 2009 - 06:52 PM

I don't know how likely it is to tip over but I moved it the day I got the mount. I have both a cg5 and a cgem and I also do AP. I feel safer with the peg over the leg. I think that it is more stable with it over the leg than between them. I hope is helps.
Dan

#4 palerider

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Posted 20 July 2009 - 07:30 PM

Richard, Dan,

Thanks for the input. I appreciate it. You've confirmed my feelings about being more stable mounted over a tripod leg than between two. Off to the garage to find the right wrench.

#5 mclewis1

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Posted 21 July 2009 - 08:34 AM

A gem is usually more stable with the counterweight bar over a tripod leg, but one issue with this orientation is the possible interference between larger diameter counterweights and the leg. If you make the change take the mount through all it's possible motions (with the counterweight(s) in various positions) to ensure that you won't have any problems ... you don't want to find them in the dark at 2am.

#6 RAKing

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Posted 21 July 2009 - 08:45 AM

I agree with all the above. :)

Most of the weight of a GEM is concentrated at the north end of the mount. Thus, putting the couterweight bar over a leg makes more sense for safety and stability.

Unless you live way down south, or use very large counterweights, you should be okay - but check first as Mark suggests.

Ron

#7 o1d_dude

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Posted 21 July 2009 - 03:04 PM

Funny this question should come up.

Just this weekend as I was setting up my gear at a star party, I remembered that my CG5 tripod shipped with the peg between the legs and I immediately moved it to the hole over a leg.

It just seems that the balance would be more stable with the counterweight over a leg rather than spread between two legs...longer lever, etc.

The correct answer? Who knows...

#8 BarrySimon615

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Posted 21 July 2009 - 04:13 PM

The CG5 clone that I had was set up so the north facing mount had the declination shaft hovering between two legs where, at least at "parade rest" it is more unstable (see those uncontrolled kids running around a living room with a telescope being displayed). In the case of my CG5 mount I sawed off the peg and repositioned it over a leg and fastened it by drilling and tapping a new threaded hole and securing with a bolt.

The other big reason for doing this is that if you are polar aligning using an alignment scope in the polar axis housing it is much easier to get up to the eyepiece (particularly if you are kneeling on the ground) if you can come up between two legs from behind. A leg in the way facing south does not help.

One would also wonder why a mount like a CG5 would be set up in such a way when most premium mounts would be set up with a leg facing north and the declination shaft oriented up and down directly in front of that leg.

Barry Simon

#9 Chris Rowland

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Posted 22 July 2009 - 08:18 AM

Most of the weight of a GEM is concentrated at the north end of the mount.

I would think that if the mount and scope are balanced the centre of gravity will be at the intersection of the Ra and Dec axes and won't move as the scope moves.
It isn't exactly over the centre of the mount but doesn't seem to be far off.

Chris

#10 RAKing

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Posted 22 July 2009 - 09:17 AM

I would think that if the mount and scope are balanced the centre of gravity will be at the intersection of the Ra and Dec axes and won't move as the scope moves.
It isn't exactly over the centre of the mount but doesn't seem to be far off.


This is where the center of gravity is located, but at my latitude it's right at the edge of the pedestal and that is too close for my comfort.

I had an Atlas a while ago and it arrived with the CW shaft setup between the legs. It was very unstable when I started loading up the counterweights, so I immediately changed the azimuth pin. YMMV! :cool:

Ron

#11 jrbarnett

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Posted 22 July 2009 - 11:58 AM

Simple answer: Yes, move the peg. It's nice to have a single leg "North". It is also more stable. I've had and seen near tip-overs with the two-legs forward configuration with some loads.

Regards,

Jim

#12 GaryML

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Posted 22 July 2009 - 01:30 PM

My CG-5 ASGT also came with the peg between the two legs. I haven't moved it and really don't see any need to move it. The mount is perfectly stable as it is, and I have not seen any tendency for it to tip north while setting it up, even with the CW shaft and weights in place and before the telescope is mounted. I'm at 32.8 degrees North. Right now I use 13 lbs of CW (the stock 11 lb plus two 1 lb toe saver weights). I've had up to 21 lbs of CW on the shaft with no problem at all. My observing locations are on a firm lawn and on gravel, so maybe on soft ground there is more of an issue.






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