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Orion Atlas EQ-G vs. CGEM

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#1 Erric

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Posted 13 January 2010 - 11:02 PM

Hi All

I know this is an old topic, the two scopes are similar, and can read reviews like everyone else.

So, the question is, which mount will last longer, more versatile, and uses newer standards?

I'm trying to decide and don't care about which one looks better.

thanks,

#2 gillmj24

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Posted 13 January 2010 - 11:45 PM

Congrats you win the prize for 100th comparison thread this year!

Just kidding (sorta) but I suggest checking these out in person before buying as the differences are largely going to come down to personal preferences and there is no correct answer to your question.
the cgem is too new to have detailed reliability studies done on it.
Mcdonalds or burger king......

#3 Erric

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Posted 13 January 2010 - 11:54 PM

good enough answer. I know this was compared 1000 times and I resisted making another post.

If the CGEM is newer, then the interfaces and standards should be newer. Knowing this helps a little.

Other than that, they should be equal at AP.

thanks...

#4 jrcrilly

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Posted 14 January 2010 - 12:06 AM

If the CGEM is newer, then the interfaces and standards should be newer. Knowing this helps a little.


The drives and controller design are older than the EQ-G but more modern (servos rather than steppers) . The CGEM firmware is continuously updated so it's more current. The Celestron controller is rich in features (it's the same controller used on the $5000 CGE Pro) while the EQ-G feature set is far smaller - to the point that it's common to use an external PC to gain functionality comparable to that of the Celestron handbox. You can, of course, extend the functionality further by use of an external PC - but it's very capable on its own.

#5 JSeay86

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Posted 14 January 2010 - 12:51 AM

I am curious about the benefits of each for astrophotography. Does EQMOD give the Atlas an advantage for long exposure astrophotography and autoguiding. Is a quick and accurate polar alignment easier with EQMOD or do most use the hand controller for initial alignment?

Thanks for the input.

#6 Erric

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Posted 14 January 2010 - 03:03 AM

I didn't read anyplace that the EQMOD gives any big advantage except for features.

While the Atlas EQ-G vs. CGEM are similar, from what I can tell, the Sirius EQ-G is better than the CG-5.

#7 Peter in Reno

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Posted 14 January 2010 - 10:13 AM

I had an Atlas EQ-G mount and C-11 scope and it was great. The only complaint I had was it's pretty difficult to raise the latitude with the wimpy latitude adjustment bolt if you have a heavy scope. Even with a light scope (e.g. 80mm refractor piggyback with 80mm Short Tube), it's still difficult. What I did was polar align using polar scope without the scope mounted, then mount the scope. You have to make sure that the latitude is locked very tight before mounting the scope. Atlas is very reliable.

I read that CGEM is extremely easier to adjust the latitude with the scope mounted. The only concern I have is the reliability of CGEM because of several failures reported in this forum. Maybe the percentage of failures is very low if many CGEMs were bought. It would be nice to know how many were sold as compared to how many failed. I think the software in CGEM hand controller is much better than Atlas especially the All Star Polar Align feature. That would be my main reason for choosing CGEM over Atlas.

Peter

#8 gillmj24

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Posted 14 January 2010 - 03:26 PM

There are many mods you can do to an Atlas/EQ-G since it has been around for some time, including a latitude adjustment mod. In time if shortcomings or improvements are found for the CGEM, mods will become known to us here as well.

I wasn't thinking about the controllers but I like Meade and Celestron much better than The Synscan controller. EQMOD makes up for that shortcoming a little bit but I don't usually observe with a laptop in the field.

My response was snarky and not toally serious, judging by the timestamp (sorry) John crilly's was a good response.

#9 Chris.Baron

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Posted 14 January 2010 - 03:35 PM

I am curious about the benefits of each for astrophotography. Does EQMOD give the Atlas an advantage for long exposure astrophotography and autoguiding. Is a quick and accurate polar alignment easier with EQMOD or do most use the hand controller for initial alignment?

Thanks for the input.


I tossed and turned myself over this one. I have and HEQ5 with EQMod and though the logical choice would have been the Atlas for the upgrade, I went the CGEM route. My thoughts are that Nexremote vs EQMod offer similar basic functionality they just go about it differently.

As for setup and polar alignment, there is a bit of a difference. If you're going to tear down and re-setup your rig every night, I found that EQMod + the Polar scope allowed for an easy and quick setup. My process was the following:

1) move to the first alignment star, adjust using a wireless gamepad to closely line things up in the RDF and then head inside for the night.
2) Platesolve and sync on the first star even if it isn't wasn't centred.
3) repeat with 2+N more stars and you're aligned.
4) move to the object of choice for imaging, platesolve, sync and reslew
5) start imaging run

Now, that isn't to say that I was perfectly polar aligned, but imaging at 3.2 arc seconds per pixel, I was fine for the most part.

The CGEM is a bit different; you have to centre each alignment star and Align on it via nexremote. There's no being lazy here. You need to do this for at least two stars, and then add a few calibration stars repeating the same process. You can software sync after that.

The above gets you aligned and you can image then, but you can then invoke the polar alignment process. This leads you through steps to get a pretty d@mn good polar alignment for that step above and beyond what I would do with the HEQ5.

The value in this is you can polar align quite accurately if you want to with just the hand controller. The downside is that you have to centre your alignment and calibration stars, so if during the process the mount is off when it slews to a star, you have to go back outside and move it to the right location so that you can fine tune it from inside.

Now in the spirit of full disclosure, I haven't imaged yet with the CGEM. I'm just telling you what I've researched and was actually doing one night before the clouds rolled back in. I now have an observatory and will have a pier shortly. Even with just the tripod, I should be able to get polar aligned just the once and be able to essentially hibernate at the end of a run and wake up and sync upon resuming imaging on another night. That said, once you're properly polar aligned with an Atlas/EQ6, the same holds true.

The reason I went with the CGEM was honestly to experiment a bit. That and the fact that I could drive to a much closer location to pick it up vs the drive I faced to go get an EQ6. In the end, sheer laziness was the deciding factor. I don't regret my decision and would not if I had gone the EQ6 route either.

Both are fine mounts for the money and I really just don't think you can go wrong with either. ADMAccessories makes customised parts for each to pretty the mounts up/replace parts with far superior parts, but the CGEM items are prettier and there are more of them. However, that just means can spend more money.

Hope this helps a bit.

Cheers,
Chris

#10 MorningStar1969

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Posted 14 January 2010 - 05:40 PM

Very technical detail here, not for those without mathematical and engineering aptitudes...
The Celestron looks a lot cooler!
However...
I would take Orion after sale/tech support over Celestron in a New York minute.
Just some details i would consider if on the market for one of these.

#11 jrbarnett

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Posted 14 January 2010 - 06:50 PM

I have the Orion Atlas EQ-G, and agree that Orion has excellent customer support, but I've likewise had great customer support from Celestron. The Celestron mount also has a longer warranty (2-years vs. 1-year), as wells as much better firmware (Nexstar vs. Synscan which updates every couple of months, has fewer features and *always* seems to have new bugs). The Orion's counterweight bar also tends to loosen during use requiring tightening of three allen screws where the bar exits the mount head just about every session. The CGEM is $100 less expensive to boot.

Were I to do it over again, I would likely choose the CGEM over the Atlas. That said, having purchased the Orion, I feel no compelling need to switch to the CGEM despite the benefits of doing so.

Regards,

Jim

#12 MorningStar1969

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Posted 14 January 2010 - 07:09 PM

Wow Jim well stated case as was the one you presented in another rather long thread of mine which at one point had me laughing for ten full minutes yet was signed, sealed and delivered.
Hearing all of that, i too would opt for the Celestron for obvious reasons.

#13 EricJD

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Posted 14 January 2010 - 07:48 PM

I've used my new-to-me Atlas EQ-G for a couple of weeks now and know nothing about the CGEM. That being said, I can't imagine anything being easier than what I do now. I set up/tear down every night and it is so easy.

With my LXD75 I needed to have an EP in for alignment, with the EQ-G I've found that getting the polar scope roughly lined up, eye-balling home position and using EQ-Mod I don't have to use an EP for alignment, I just keep the DSI 3 on and align with it; three stars and done. Takes me all of 30 minutes to haul everything out to the backyard, get aligned and start imaging. So far I've not gone beyond 5.5 minute exposures but I haven't had to throw away a single one yet, they've all been spot on using PHD to guide.

#14 MorningStar1969

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Posted 14 January 2010 - 08:10 PM

Eric, is the Atlas a lot less noisy than the Meade LXD?
I have heard that they are very quiet when slewing and though my CG5 was solid and accurate, i was very annoyed by the wining motors. i have almost considered an Atlas type mount just for this reason. Not to hijack the thread, but what is the decibal level of the Orion Sirius mount, if anybody else wants to chime in?

#15 EricJD

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Posted 14 January 2010 - 11:20 PM

Compared to the LXD75 it's as quiet as a church mouse.

#16 BKBrown

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Posted 14 January 2010 - 11:31 PM

Eric, is the Atlas a lot less noisy than the Meade LXD?
I have heard that they are very quiet when slewing and though my CG5 was solid and accurate, i was very annoyed by the wining motors. i have almost considered an Atlas type mount just for this reason. Not to hijack the thread, but what is the decibal level of the Orion Sirius mount, if anybody else wants to chime in?


It's very quiet and definitely won't offend the neighbors in the middle of the night. I have found the Atlas to be easy to set up and maintain, and it's solid as a rock. The polar scope makes alignment a breeze and virtually ensures decent tracking if done properly. For a very modest investment you can add EQMOD and pretty much run the thing with a game pad; the lap top interface provides very discrete control. In addition, ADM makes an outstanding line of upgrade parts (I think they have them for CGEMs as well) that really beef up the mount. With the Atlas' long track record, extensive selection of upgrades, on line user support, and the first rate service available from Orion I feel very comfortable that it is a solid piece of equipment I will be able to rely on for years to come. Clear Skies, BrianB. :waytogo:

#17 John J

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Posted 15 January 2010 - 02:02 AM

Here is my :penny: :penny:
I recently rebuilt a CG5 AGT for one of our club members. Celestron carries a lot of their engineering practices from one mount to the other. First off they use DC gear head servo motors. DC motors have brushes that will eventually wear out. The gear head inherently has lots of backlash. Gear heads with straight cut gears are noisy. They use the gear head to get the required torque from a relatively small DC motor. The servo system is a closed loop type that is always trying to move the mount to a specified encoder position. If the mount is unbalanced or encounters an obstruction the closed loop system will keep commanding the motors to match the encoder position required. It does this by increasing the amount of current to the motor. This can lead to armature burn out. The encoder is a 200 step per revolution type which equals 1.8 degrees per tic.

The EQ-6 uses stepper motors. Stepper motors have no brushes and have more torque. The motors are direct drive to the worm gear through 2 spur gears. Stepper motors are very quiet. Stepper motors move by advancing the windings and always see the same amount of current no matter what the load. If a stepper motor is over loaded or encounters and obstruction it will stall. The current remains the same and it will continue to advance the windings and the motor will chatter but there will be no damage. Stepper motors are 200 steps per revolution or 1.8 degrees per step. The synscan uses the motor steps as it's encoder. It takes for granted that it told the motor to step and it did. If the motor stalls it will require a re-alignment.

That is a review of the two systems that I am familiar with. It was meant for comparison of the motor drive systems and how they work. I like the EQ-6 system as it uses stepper motors that will practicably last forever and less electronics are involved in the control of the mount position. Less electronics = more reliability.

I own one of the earliest EQ-6 GTs (the old charcoal grey). It has operated flawlessly for well over 5 years now. When the CGEM came on the scene I seriously considered side stepping to that unit. With all the software offerings for the Atlas and EQ-6 type mounts though I just can't justify leaving such of a robust system behind. Not having to worry about motor burnout or brush wear is a plus for the EQ-6. The reduced complexity of the electronics is another plus for the EQ-6. Direct drive to the worm and no gear head is another plus. After market software another plus and on and on.

This is just my opinion but I find that the EQ-6 in the very long run, will be the most robust system of the two due to it's simplicity and rugged construction.

JJ

#18 Erric

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Posted 15 January 2010 - 03:03 AM

To all.
After lots of reading and asking, I decided on the Atlas EQ-G.
This should serve me well as my first and only mount for many years.

I also thought of the Sirius and CG-5, but they may not have the steadiness needed for AP after I add the guide-scope, camera, etc.

thanks for all the help!

#19 rmollise

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Posted 15 January 2010 - 09:21 AM

To all.
After lots of reading and asking, I decided on the Atlas EQ-G.
This should serve me well as my first and only mount for many years.

I also thought of the Sirius and CG-5, but they may not have the steadiness needed for AP after I add the guide-scope, camera, etc.

thanks for all the help!


Next step? Go here and start learning about EQMOD; it's what makes the Atlas shine. ;)

http://eq-mod.source...introindex.html

#20 dscarpa

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Posted 15 January 2010 - 03:52 PM

I would like to see Orion use alignment hardware like the CGEM's which looks very easy to use. My CG5GT's is a pain to use and looks similar to the Atlas. David

#21 Rick Rick

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Posted 11 November 2010 - 12:47 PM

I'm curious to know how you like the CGEM now that you've had it a while. I'm going to buy one today, but am a little concerned about the gearmotor backlash and noise as compared to the Sirius EQ-G

#22 bbbri

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Posted 11 November 2010 - 05:39 PM

I have 2 CGEMs currently being repaired by Celestron. Both have problems with electronics. I'm missing a lot of clear skies this month. I may go with Losmandy next time.

#23 Lane

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Posted 11 November 2010 - 08:39 PM

Some people have had CGEM problems but I suspect that most owners have not. The problem CGEM's just get reported and discussed more often. I have had my CGEM for almost 2 years now and so far no problems at all. Just buy from someone willing to take it back if there is something wrong. OPT will take it back for certain, I believe Astronomics would as well. Don't know about the other companies out there and their return policies. Just save all the cartons and bags.

The CGEM is louder than the Sirius and the Atlas, but not as loud as an LX200. So it isn't really that bad, but the quiet smooth sound of the Atlas and Sirius is pretty nice.

There is nothing really wrong with buying the Atlas either, I would be perfectly happy with one of those. Their hand controller software is not as nice as the CGEM, but it isn't exactly terrible either, it just lacks a few features. I don't like their saddle plate so I would replace that with an ADM plate, but I replaced the one on the CGEM too, so there is no advantage there. The main reason I went with the CGEM is because when you buy it paired with an SCT it saves you some serious cash.

I was looking yesterday at the price of the EdgeHD 11 OTA compared to the prices of the CGEM EdgeHD 11. The difference is only $700. So if a person is going to buy the 11" scope anyway they can get the CGEM for just 700 more. That's a good deal.

#24 jrbarnett

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Posted 11 November 2010 - 11:31 PM

Actually on the thread soliciting positive and negative CGEM experiences (rather than asking for problem reports) over 40% of the CGEM owning respondents indicated that they had experienced QC problems with their mounts.

Though I don't think Losmandy is a panacea to poor Celestron QC. Half of the Losmandy Gemini mounts purchased by club mates have arrived with non-functional electronics. There've even been a couple of Takahashi mounts with bum electronics in the club over the years.

Of the cheap mounts, the Atlas seems to be least problematic. Otherwise, save you pennies for an Astro-Physics mount if you want a relatively troublefree experience.

You're right though about buying a CGEM + SCT bundle. You can save a bundle. In fact, you could likely sell a new, unopened CGEM for $1000 and pocket the extra $300 if you really just wanted an OTA.

Regards,

Jim






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