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Equipment Discussions >> Mounts

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hfjacinto
I think he's got it!
*****

Reged: 01/12/09

Loc: Land of clouds and LP
Re: CGEM -- first impressions new [Re: jrcrilly]
      #4560901 - 05/04/11 09:38 AM Attachment (37 downloads)

Amys,

The first CGEM I had the following issues:
1) Way too much slop, the mount would move an inch in alt and dec.
2) One of the screws was stripped on the housing
3) Part of the mount housing was cracked
4) Motor Fault errors.

The best I can tell was that the mount was dropped and something broke inside. As soon as I tried it the first time, I knew something was wrong. It would tick, tick, tick, tick while tracking. When I started looking at it, I saw the crack, the stripped broken screw and realized the mount was damaged. OPT took really good care of me, so if you buy from a good dealer, you should have no issues.

The second mount has worked well for almost a year and tracks very well.


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Helcarexe
Pooh-Bah


Reged: 12/24/10

Loc: Des Moines, Iowa
Re: CGEM -- first impressions new [Re: hfjacinto]
      #4560908 - 05/04/11 09:43 AM

Nice image it does look like the mount is working, its good to hear that a dealer will take care of its customers.

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AntarcticDave
sage


Reged: 02/03/09

Loc: Denver, CO
Re: CGEM -- first impressions new [Re: Helcarexe]
      #4560933 - 05/04/11 10:00 AM

I have had mine for a bit over 2 years and it's still working just fine.

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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: CGEM -- first impressions new [Re: jrbarnett]
      #4560996 - 05/04/11 10:32 AM

Quote:

I had a chance to play with a CGEM at the last club star party. I fielded an Atlas. It was nice to see both mounts in action at the same time.

The CGEM is better finished, and much more ergonomic than the Atlas. It goes without saying that the Nexstar firmware is light years ahead of Synscan on the feature front. The CGEM also slews to targets MUCH faster than the Atlas (I'd estimate >2x the slew rate).

On the other hand, the CGEM is much noisier in operation than the CGEM, and the particular unit we were using suddenly bound up in its declination axis during the session. It had been "hypertuned" professionally, and I suspect something had been either meshed too tightly or left too loose. By the cold light of day the owner discovered that the declination worm adjustment screws were loose, and tightening them fixed the glitch. Whew!

My Atlas hasn't missed a day of school since I bought it many years ago.

I really liked the CGEM and if I was going to refresh my aging Atlas, I'd definitely consider it. My only misgiving is the less than stellar reliability reports and my own observed failure of the unit I had the opportunity to use.

Regards,

Jim




Just a note on this mount. If it is the mount I think it is, the owner got it second hand after the original owner had made some adjustments and apparently either left the bolts loose or they somehow got loose in shipment. They were not loose from the service on the mount and it was not a defect in the mount. This mount has also been shipped very long distances including to Canada and mounts that travel like that may frequently need fine adjustment afterwards to account for environmental changes, especially if the mount has been previously fine tuned to remove as much backlash as possible. Again, it is not a defect in these mounts, just a fact of life.


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jmiele
Patron Saint?
*****

Reged: 12/04/10

Re: CGEM -- first impressions new [Re: EFT]
      #4561102 - 05/04/11 11:40 AM

IMO, shipping mounts and telescope long distances is a fact of life. If manufaturers are making gear that cannot be shipped and still perform to a certain level, then that is a problem. Upon arrival, ANY of the gear from ANY maker, should perform to the documented spec. And it's NOT the carriers fault. We too often want to blame UPS and FEDEX. Poor design and packaging are the main reason things arrive out of spec. Can you ship Eggs via UPS.....? Sure you can, but not in the catron you buy at the supermarket. But as we learned in school, you can make a carton or package to support dropping the egg from the 2nd floor window without it breaking. Telescope and mount makers need to make gear and packaging the can live within the current delivery systems because we aren't going to pick everything up at the shop

3,4 maybe 5 cents

Joe


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jmiele
Patron Saint?
*****

Reged: 12/04/10

Re: CGEM -- first impressions new [Re: jmiele]
      #4561117 - 05/04/11 11:46 AM

Just to add to that - Celestrons packaging is as BAD as it gets. They ship a $4500 C-14 in less than 100lb burst strength cardboard. They only support and protect the tube at the ends with foam. You can push the box with your hands until you hit the tube at the center. If you are to use the same box again to send to someone else it will fail. Then everyone is mad at UPS/FedEx when they won't pay a claim. Joe

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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: CGEM -- first impressions new [Re: jmiele]
      #4561152 - 05/04/11 12:03 PM

Quote:

IMO, shipping mounts and telescope long distances is a fact of life. If manufaturers are making gear that cannot be shipped and still perform to a certain level, then that is a problem. Upon arrival, ANY of the gear from ANY maker, should perform to the documented spec. And it's NOT the carriers fault. We too often want to blame UPS and FEDEX. Poor design and packaging are the main reason things arrive out of spec. Can you ship Eggs via UPS.....? Sure you can, but not in the catron you buy at the supermarket. But as we learned in school, you can make a carton or package to support dropping the egg from the 2nd floor window without it breaking. Telescope and mount makers need to make gear and packaging the can live within the current delivery systems because we aren't going to pick everything up at the shop

3,4 maybe 5 cents

Joe




Joe,

You are generally correct and the CGEM in fact comes in a very good shipping box and packing. One of the best and far better than styrofoam packing. And for the most part, when a mount arrives it does work unless it has had very wrough treatment. I have yet to get a CGEM damaged in shipping. However, two things were different about this mount. First, it was not coming from the manufacturer or the dealer, it was coming from the original owner. Second, the mount had been previously adjusted to mesh the gears very tightly. That is not how they come from the manufacturer. In general, the adjustment of a mount from a manufacturer is loose enough to allow for shipment to different environments where the expansion and contraction of the different metals can affect the functioning of the mount. When you change those adjustments or have them changed in order to tighten up the mount you need to realize that fine readjustment may be necessary when it travels or is shipped long distances.

I am located in Phoenix, Arizona and I find that when I really tighten a mount up and then send to places with much different climates (like cold Canada or very humid Louisiana or Florida) a little fine readjustment may be necessary when the mount arrives at its destination because things may have either tighten or loosened up in the process. This is probably less the case with higher quality mounts that use flat metal plate machined construction, but with mounts that mix machined and cast metal parts I see it fairly often. For the most part, I don't think that it is attributable to handling in shipping. In general most mounts are actually pretty tough pieces of equipment that can handle a fair amount of abuse in shipping and tavelling without and real problems. About the only shipping damage I ever see, even with poorly packed mounts, is a bent adjustment bolt or a cracked plastic housing on a lower end mount and I get mounts from and send them to everywhere in the country and Canada.


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Mike Wiles
scholastic sledgehammer


Reged: 02/04/09

Loc: Goodyear, AZ
Re: CGEM -- first impressions new [Re: jmiele]
      #4561168 - 05/04/11 12:09 PM

My CGEM has performed admirably in the six months that I've owned it. I've set it up and taken it down perhaps 30 times in that period and I've had no issues. I do a 2 star alignment, and then 4 calibration stars. After that, I use the all star polar alignment routine to nail down the polar alignment. Many people will turn off the CGEM and start all over at this point. I simply slew to another bright star, sync to that star and get busy imaging.

The mount tracks well, autoguides well and does everything I ask of it every time I do it. I couldn't be happier with it - especially for what it cost.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: CGEM -- first impressions new [Re: jmiele]
      #4561178 - 05/04/11 12:13 PM

Quote:

Just to add to that - Celestrons packaging is as BAD as it gets. They ship a $4500 C-14 in less than 100lb burst strength cardboard. They only support and protect the tube at the ends with foam. You can push the box with your hands until you hit the tube at the center. If you are to use the same box again to send to someone else it will fail. Then everyone is mad at UPS/FedEx when they won't pay a claim. Joe




I haven't seen a C14 in the box but all of the C11s I have seen came in double boxes that were pretty good although not as good as the mount boxes. They use to come packed in the expanding foam that was better though. Some manufacturers use that stuff and it works pretty well. Considering the size and wieght of the C14 I would definitely want that double boxed and probably center supported.

If you ever need to ship something that was poorly boxed in the first place, that is the only time I will go to a pack-and-ship place to have them use the expanding foam material for packing. But you have to watch how they do it and make sure it is done correctly. For the most part I never recommend allowing someone else to pack your gear since they will just throw it in a box with peanuts and call it good. That is how gear gets broken in shipping. Peanuts are OK as long as the item being shipped is also very well wrapped in bubble wrap and cushioned with the peanuts packed tightly so that the item cannot just bounce around in the box.


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amys
Carpal Tunnel
*****

Reged: 06/12/06

Loc: Groton, CT
Re: CGEM -- first impressions new [Re: EFT]
      #4561219 - 05/04/11 12:26 PM

Just a quick set up question: how much should you tighten the RA and DEC knobs after balancing? With my Sphinx, I make them good and tight but every mount is different.

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BCB
Undercover Saboteur
*****

Reged: 11/24/03

Loc: Look over your shoulder
Re: CGEM -- first impressions new [Re: amys]
      #4562770 - 05/05/11 05:38 AM

Make em tight.. Wont hurt a thing. The worm gears are double bearing (top and bottom) unlike the cg5 style of just smooth inner mating surfaces.

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amys
Carpal Tunnel
*****

Reged: 06/12/06

Loc: Groton, CT
Re: CGEM -- first impressions new [Re: BCB]
      #4562890 - 05/05/11 08:07 AM

OK, thanks. I'll pass that along.

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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: CGEM -- first impressions new [Re: amys]
      #4562954 - 05/05/11 09:05 AM

Quote:

Just a quick set up question: how much should you tighten the RA and DEC knobs after balancing? With my Sphinx, I make them good and tight but every mount is different.




The clutches on the Sphinx work much differently from the CGEM. If you clamp down on the CGEM clutches you will slightly deform the ring gears and the mount will run very poorly due to the gears no longer being round. You need to use as little pressure as possible on the CGEM clutches.


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clchildress
Pooh-Bah
*****

Reged: 04/22/10

Loc: NW Georgia, USA
Re: CGEM -- first impressions new [Re: EFT]
      #4562968 - 05/05/11 09:20 AM

Quote:

Quote:

Just a quick set up question: how much should you tighten the RA and DEC knobs after balancing? With my Sphinx, I make them good and tight but every mount is different.




The clutches on the Sphinx work much differently from the CGEM. If you clamp down on the CGEM clutches you will slightly deform the ring gears and the mount will run very poorly due to the gears no longer being round. You need to use as little pressure as possible on the CGEM clutches.




That's good information to have! I just acquired a used CGEM and the last thing I'd want to do is damage it, ham-fist style.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: CGEM -- first impressions new [Re: clchildress]
      #4562994 - 05/05/11 09:35 AM

Quote:

That's good information to have! I just acquired a used CGEM and the last thing I'd want to do is damage it, ham-fist style.




The gears seem to spring back reasonably well so if you have been overtightening the clutches you are probably OK. Its just that you can really tell when the mount is running with oval shaped gears. Two opposite quarters of the gear will run smooth and loose while the other quarters will bind and it is only temporary PE since the positions will change whenever you release the clutches. Even in these mounts changes of 100ths or 1000ths of an inch can make a significant difference sometimes.


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: CGEM -- first impressions new [Re: EFT]
      #4563911 - 05/05/11 05:50 PM

On the other hand, I've never had to touch the Atlas in this regard. Mine is many, many years old, is well traveled (including many off pavement dark sky trips) and has not been treated gently in any way.

I find it strange that a much younger and less traveled CGEM would manifest this issue unless caused by human intervention, when a much older, untouched, more abused Atlas would not. Would it be legit to use Locktite blue on these screws to avoid having to deal with the loosening screw issue in the future?

- Jim

Edited by jrbarnett (05/05/11 06:01 PM)


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Phil Cowell
Carpal Tunnel
*****

Reged: 05/24/07

Loc: Southern Tier NY
Re: CGEM -- first impressions new [Re: jmiele]
      #4563917 - 05/05/11 05:53 PM

Quote:

Can you ship Eggs via UPS.....? Sure you can, but not in the catron you buy at the supermarket. But as we learned in school, you can make a carton or package to support dropping the egg from the 2nd floor window without it breaking. Joe




Joe you can put a house brick in 3 meters of packing and foam. Even that stuff they show on the ads for pillows that stop stop eggs being broken and you'll have house brick dust by the time it arrives. They teach these guys how to trash military survive space flight stuff.
The test sheets read:
1, 150' drop test....Passed
2, 60G edge impact....Passed
3, 60MPH vehicle impact.....Passed
4, Shoot from chicken cannon into aircraft windscreen.....Passed
5, Fedex, UPS test 500mile delivery test....Failed both carriers, nothing but dust in both containers.

They could trash anything and take pride in it.


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Phil Cowell
Carpal Tunnel
*****

Reged: 05/24/07

Loc: Southern Tier NY
Re: CGEM -- first impressions new [Re: jmiele]
      #4563923 - 05/05/11 05:55 PM

UPS/Fedex have the same logo now....

The jobs not done until any delivered product won't run.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: CGEM -- first impressions new [Re: jrbarnett]
      #4563965 - 05/05/11 06:16 PM

Quote:

On the other hand, I've never had to touch the Atlas in this regard. Mine is many, many years old, is well traveled (including many off pavement dark sky trips) and has not been treated gently in any way.

I find it strange that a much younger and less traveled CGEM would manifest this issue unless caused by human intervention, when a much older, untouched, more abused Atlas would not. Would it be legit to use Locktite blue on these screws to avoid having to deal with the loosening screw issue in the future?

- Jim




If someone has a persistent problem with the worm gear housing bolts loosening up, then some medium strength (usually blue) threadlock on these bolts is fine. However, I have generally not heard of people having this problem. It is more common, when a mount is set very tight and shipped to a different climate, that a little fine adjustment may be necessary sometimes to counter the effects of differential expansion and contraction in the mount that may cause the gears to become a little more tight or loose (you probably won't notice loose but you will definitely notice tight).


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jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: CGEM -- first impressions new [Re: EFT]
      #4564051 - 05/05/11 07:20 PM

Thanks Ed. Makes sense.

Regards,

Jim


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