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Orion Atlas EQ-G

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#1 Mantis707

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Posted 10 September 2012 - 05:10 PM

Hello,

I have been lurking the forums trying to absorb everything I can. I am going to be getting back in to Astrophotography....I have assessed my gear, and basically what I have right now that is serviceable is:

1) A meade 8" SCT (F/10)
2) eyepieces, t-rings,Barlows etc...
3) A meade tripod


After doing all kinds of reading and research I believe I am going to purchase the Orion Atlas EQ-G mount....Basically it came down to that orthe CGEM or CGEM DX....Originally I was thinking of getting a losmandy G-11 so I could be ready for more payload, but that would require me to save up for a while longer, and I really want to start this fall/winter taking some pictures.

Anyway:

1) Is it true that the CGEM has more 'plastic gears' than the Atlas? (where as the atlas has some steel gearingthat is plastic in the CGEM) I could not confirm this, but I read that on another site.

2) The Atlas is being sold on a sale with a 10" F 4.7 newtonian refractor for about $250 or so more than the list price of the mount alone. Is this a scope I could do imaging with? Or is it too heavy for the mount + AP gear? I am really mainly interested in imaging right now, and will do very little visual at present. Any other thoughts on imaging with this rig?

3) ANy reasons to consider the CGEM or CGEM DX ? I see the DXis about 500$ more...but it seems like the same unit, with a beefier tripod and weights....

If I got the 10" newtonian, I could probably sell my 8" SCT for a couple hundred and save money towards photo gear.....but I am worried that it (the 10" newt) is pushing the limits of the mount. I looked on astrobin, and I see quite a few 8" newtonians on an atlas, but I couldnt find any 10" newt / atlas pics...

Thanks and I would love to hear any other thoughts between the cgem or cgem dx versus the Atlas as well.

Mantis707

#2 Mantis707

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Posted 10 September 2012 - 07:04 PM

I just realized I posted this to imaging,because in my mind I was thinking of doing mainly imaging with this setup, but I suppose it could have been better off in the mount section? My questions are mainly about the mount but I would also like some opnions on whether the 10" orion newtonian would be good for imaging with this setup.

#3 dhaval

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Posted 10 September 2012 - 07:34 PM

I would go with the Orion primarily because it is much more reliable - Orion does a better job than Celestron in terms of consistency of their products.

That being said, I am not sure (primarily because I am not aware of the scope that you are talking about) if either of these mounts will carry the weight of the OTA and any guidescope that you may want to put on the scope.

Another thing - and I am not sure if you have given this enough thought - but I would not begin imaging with a F10 scope - that is just too long a FL for beginning imaging (of course, I am assuming that you are "beginning" imaging). The learning curve will be too steep . I would much rather begin with a F6 or faster scope - or at least put a reducer on your scope.

To answer your second question - I would limit the scope to the 8in reflector - that would be a much nicer scope for imaging with the Atlas. In either case, you might have to change the focuser on the scope - a Moonlite will do quite nicely.

Hope the above helps.

Thanks,
Dhaval

#4 jgraham

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Posted 10 September 2012 - 07:47 PM

I've done quite a bit of imaging with my LXD75 SC8 and I really enjoyed the versatility of the SC8 system. A couple of months ago I upgraded the mount to an Orion Atlas EQ-G and this has proven to be a fantastic mount for the SC8. Absolutely rock solid and the SC8 is comfortably over-mounted (which is a good thing). In fact, I've got it sitting outside right now. If'n it were me, I'd go for the Atlas, keep the SC8, and be happy. And yes, I do most of my imaging with the SC8 in its native f/10, but I'll bring it in to f/6.3 when I want to go a bit wider. The SC8 also stretches out real well to f/30 for planetary imaging. I don't see much upside to a 10" Newtonian unless it were an SN10.

Have fun shopping around!

#5 Mantis707

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Posted 10 September 2012 - 09:13 PM



I really don't care too much about the newtonian, but for an extra $250 it seemed like a great deal....($1750 versus $1500 for just the mount)....That is the main reason I am considering the newt.

#6 terry59

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Posted 10 September 2012 - 11:33 PM


I really don't care too much about the newtonian, but for an extra $250 it seemed like a great deal....($1750 versus $1500 for just the mount)....That is the main reason I am considering the newt.


Orion likes to bundle things. I guess it's a good business model for them. I'd recommend you use the $250 toward an autoguider instead.

This advise was worth everything you paid for it :grin:

#7 Mantis707

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Posted 11 September 2012 - 12:04 AM

Thanks Guys!!! I really apprecite it.....I guess I was thinking if all else failed. I could sell one of the OTA's and i would be ahead in the game....Ive never used a newtonian and the thought of having a 4.7 focal ratio was semi appealing for imaging....but it sounds like I should maybe just hold on and try to get the mount by itself...maybe on sale...

#8 Mantis707

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Posted 11 September 2012 - 12:06 AM

Dhaval - thanks or the tip on the focuser...I will research it.

#9 TexasRed

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Posted 11 September 2012 - 01:03 AM

I've had the combination of the Atlas EQ-G mount and the 10" f/4.7 newt for visual use and sold them. The eyepiece required a ladder to see through, and I wound up doing so at some fairly awkward angles. I don't know anything about photography, but that was the only drawback I found to that combination of scope and mount for visual use. Otherwise, it's a great scope and a great mount.

Mine was bought by a man who planned on putting a smaller scope on that mount for photography and finding a Dob mount for the scope for visual use. That sounded like a really good plan to me!


#10 orlyandico

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Posted 11 September 2012 - 02:39 AM

Yup buy it with the big newt, build a dob mount for the newt so you can look at stuff while imaging. The 10" is way too heavy (and long) to image with an Atlas.

#11 Mkofski

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Posted 11 September 2012 - 09:02 AM

Orion has the Atlas EQ-G with an 8" newt on sale for same price as the mount alone. Buy that package and I'll give you $20.00 for the newt and you'll be ahead!

#12 EFT

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Posted 11 September 2012 - 09:19 PM

1. The Atlas has not plastic gears. The CGEM has one nylon gear down in the servo motor gearbox. It is there for a reason and is a common feature in servo motors like these. It purpose is as a safety feature. If the axis is jammed (like when the scope hits the tripod), the nylon gear will strip before damage is done to the spur gears or worm and ring gear. The existance of this one nylon gear is not a detractor.
2. I would not recommend the 10" newt. Too much load, bad eyepiece position, etc. Adding AP gear only makes it worse. In fact, I would rarely ever recommend buying a bundle that includes the manufacturer's largest scope on the mount since it is usually optomistically under mounted. I agree that the money would be better spent on a guider which is a necessity.
3. CGEM and CGEM DX are equally good mounts as the Atlas and if you are looking to buy used, I would actually recommend them since Celestron does support people with mounts that were not purchased from them or one of their dealers. Orion will only support mounts perchased from them by the person seeking support (i.e., parts or repair). I personally recommend the CGEM over the CGEM DX. If you need more stability, add and after market spreader rather than a tripod that weighs as much as the mount.

Keep the M8, but if you are just starting on AP, don't start with it. Start with a refractor or a small (8 inch or less) imaging newtonian and work you way up to the M8.

#13 Mantis707

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Posted 12 September 2012 - 01:41 AM

Thanks Mr. Thomas!!! I will heed your advice. Thanks everyone for helping me. I spent tonight under the stars just visually....showed my wife some things...she said "cooooool" when m13 resolved into "diamond sparkles" (her words)...first time in years under the stars.

#14 rmollise

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Posted 12 September 2012 - 07:04 AM

I would go with the Orion primarily because it is much more reliable - Orion does a better job than Celestron in terms of consistency of their products.


Well... The CGEM and the EQ-6 are made by exactly the same folks, Synta, just marketed under different labels.

#15 jrbarnett

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Posted 12 September 2012 - 02:32 PM

With different motors, and gear trains, and different firmware.

The CGEM presently isn't playing nicely with the latest Nexstar Firmware and Celestron even has a beta test program for users to help test fixes.

The Atlas just works. The CGEM ain't never been quite right from the get-go, IMO, and they're still futzing with it. I kinda think dhaval makes a valid point.

- Jim

#16 EFT

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Posted 12 September 2012 - 02:48 PM

With different motors, and gear trains, and different firmware.

The CGEM presently isn't playing nicely with the latest Nexstar Firmware and Celestron even has a beta test program for users to help test fixes.

The Atlas just works. The CGEM ain't never been quite right from the get-go, IMO, and they're still futzing with it. I kinda think dhaval makes a valid point.

- Jim


First I have heard of an issue with the most recent firmware. I know that they are trying out some new firmware to address an issue that some people have with DEC motor cogging, but in that regard, Orion is beta testing new firmware too to try to bring it up to the CGEM's capabilities, so they are futzing as well. Those are actually good things meant to improve the mounts and their capability.

As Rod pointed out, dhaval did not have a valid point regarding consistency or manufacturing (his other points regarding mount selection and capacity were valid).

Do you or did you have a CGEM Jim? I can say without a doubt that the term "just works" applies or does not apply just as well to the CGEM as it does the Atlas and I should know. There are some mechanical design issues with the Atlas that have never been fixed and probably never will be. Issues that were actually addressed when they designed the CGEM believe it or not.

In the long run, you are good with either mount.

#17 Aurneth

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Posted 22 September 2012 - 11:29 PM

I've had the combination of the Atlas EQ-G mount and the 10" f/4.7 newt for visual use and sold them. The eyepiece required a ladder to see through, and I wound up doing so at some fairly awkward angles. I don't know anything about photography, but that was the only drawback I found to that combination of scope and mount for visual use. Otherwise, it's a great scope and a great mount.

Mine was bought by a man who planned on putting a smaller scope on that mount for photography and finding a Dob mount for the scope for visual use. That sounded like a really good plan to me!


Funny, I recently bought a 10" f4.7 Newt on an EQ-6 for $1200 with the intent of using my older 8" LX3 OT on it for AP and with a future plan of acquiring an Apo in the 90-120 mm range. The price I paid for the package along with a miscellany of accessories - probably a few hundred dollars worth - is less than what I would have to fork out for a new EQ-6 alone, so I figured it was worth it as I would also have a large aperture scope for visual use.

I hadn't expected the Newt to be such a PITA to use visually, though. The eyepiece gets to all sorts of annoying positions and loosening out the rings to rotate it is not too fun in the dark. I'd love to know who thought putting a Newt on a GEM was a good idea - those things should be base-mounted, whether as a Dob or with a fork or split-ring equatorial.

I may indeed build a Dob mount for the 10" just to make it more usable visually. Maybe I can modify the old LX3 base...

#18 rmollise

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Posted 23 September 2012 - 08:13 AM

With different motors, and gear trains, and different firmware.

The CGEM presently isn't playing nicely with the latest Nexstar Firmware and Celestron even has a beta test program for users to help test fixes.

The Atlas just works. The CGEM ain't never been quite right from the get-go, IMO, and they're still futzing with it. I kinda think dhaval makes a valid point.

- Jim


Let me put it this way: I love the Atlas' solidity and reliability, but if I buy another mount in this class it will be the CGEM and I won't have any hesitation doing so. The NexStar firmware is just _better_, even given the recent upgrades to SynScan. ;)

#19 jrbarnett

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Posted 23 September 2012 - 07:13 PM

Ed, I can only go with what I've actually seen and used in the club. 2 CGEMs with multiple issues, including one you Hypertuned, and 3 Atlases with no issues, including my own, which has seen years and years of trouble-free, hard use. As of yet, I've not personally seen a CGEM that did NOT have significant issues within the first year or two. At this point I would have a very hard time buying a CGEM as a result.

Also when you read this forum there are at least ten complaint threads involving a CGEM for every one involving an Atlas. It's also not as if the CGEM hasn't been out long enough for Celestron to get a handle on the issues.

Lastly, aren't the mounts you receive the ones that the owners have found to be deficient in some regard? A mount that "just works" for the user's intended use doesn't get sent to a tuner. What's your Atlas to CGEM "tune-up" ratio these days?

Regards,

Jim

#20 Pat at home

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Posted 24 September 2012 - 06:49 PM

If ever I want a mount bigger than my EQ-6 it will very likely be an EQ-8 (or whatever they end up calling it). I've had the EQ-6 for over 7 years now and it has always worked as promised. Heavy? Yes. Ugly? Maybe. Old technology? Yes. Rugged and reliable? Most definitely.

My opinion.

#21 EFT

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Posted 24 September 2012 - 07:08 PM

Jim,

What is the significant issue? The most common issues that I see with the CGEM are exactly the same as with the Atlas, inbility to balance and poor error for AP work related mostly to fit and finish and final assembly issues. While I have seen few of either, I have seen 1 or 2 more bad Atlas motor boards than CGEM motor boards.

I don't know about 10 times as many complaint threads but I do know about 10 times as many people who love to bash on Celestron every chance they get.

The CGEM is not perfect but neither is the Atlas. In fact, the Atlas has some major design flaws that were addressed with the CGEM like the counterwieght bar, latitude adjustment, clutch placement and saddle. In all these years, the only thing addressed on the Atlas has been the saddle.

The mounts that I receive for HyperTuning are not necessarily deficient in any respect, that's why I get a fair number sent right from the dealer or from a used seller. The average CGEM or Atlas is a good visual performer and a mediocre AP performer. The majority of mounts that come to me (including Celestron, Orion and Losmandy) are sent so that they can be good AP performers. If you talk to the mount designers, they will tell you that the mounts are designed and built within set cost constraints like any business. Anything above that cost has to be left to the aftermarket servicers and upgraders to take care of for those people who desire or need that additional bit of performance. I work on many mounts that "just work." They get sent to me so that they work even better. The ratio of Atlas to CGEM HyperTunes or kits has always been and remains about the same.

Ed.

#22 artcarter

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Posted 24 September 2012 - 10:47 PM

How does the iEQ45 from IOptron compare to the CGEM or the EQ-G?

#23 orlyandico

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Posted 24 September 2012 - 11:44 PM

The CGEM has a very well known 8/3 periodic error (182-second period) that cannot be corrected with PEC. This error varies widely in magnitude, on my CGEM it is 22" which is larger than the fundamental.

Another poster here (Luke) reports a 5" magnitude fast periodic error with a 6.2-second period on his iEQ45, this cannot be corrected by autoguiding or PEC because it's too fast (almost 1" per second).

Both of these cases, the error is in the motor gearbox.

The Atlas / EQ6 has a dead-simple one-stage gearbox with a 12-tooth gear on the motor, and a 47-tooth gear on the worm (with an idler in between). I have no proof for this, but I believe the simpler gearbox means there is less chance of gearbox-induced periodic errors.

That is just my theory though.

From a mechanical perspective I think they are all more-or-less equivalent. The fundamental periodic error (of the worm gear) will be similar in magnitude - and in general is not a problem since it is so slow (480-second period) so can be guided out.

It is the gearbox errors which are hard (or impossible) to guide out - but if they are small, they will not be a problem either. The 5" fast periodic error in the iEQ45 can probably be lived with - bouncing of the guide star due to seeing will be at the 2" to 3" level anyway.

The CGEM's huge 8/3 cannot be ignored - but it's slow, so can be guided out. What this means though is - for my CGEM at least with its huge 22" 8/3 error - is that autoguiding is required. My CGEM cannot be used for unguided imaging at all except at very short focal lengths and for exposures much less than 182 seconds.

But then almost everyone with this class of mount auto-guides. So probably still not an issue anyway.

#24 EFT

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Posted 25 September 2012 - 09:51 AM

If you want to see what I consider to be a significant issue with this mount, just look at this thread:

http://www.cloudynig.../o/all/fpart/1.

#25 Phil Sherman

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Posted 26 September 2012 - 01:22 PM

A few days ago, I was doing some tracking experiments with my Atlas mount to help out a friend who is having problems getting his tracking working. The two attached pictures are each composites of the same four 10 minute exposures of the area around Gamma Triangulum, which was close to the zenith when imaged. The first one is a merge of the calibrated images, the second a merge after alignment of the individual images. Guiding was done using a webcam (not my usual guide camera) on an 80ST with PhD, where the guide star had a S/N ratio of around 12, possibly a bit less. This is a portable astro imaging setup and also doesn't have perfect polar alignment. Images were taken using an unmodified Canon T3i camera at prime focus of an 8" f/4.9 Newtonian reflector. A Baader MPCC was used to help control coma at the edges of the FOV.

Note: I'll need to send the pictures as two separate posts.

Phil

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